[Federal Register Volume 81, Number 120 (Wednesday, June 22, 2016)]
[Rules and Regulations]
[Pages 40534-40547]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-14540]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2015-0144; 4500030113]
RIN 1018-BA94


Endangered and Threatened Wildlife and Plants; Threatened Species 
Status for the Elfin-Woods Warbler With 4(d) Rule

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine 
threatened species status under the Endangered Species Act (Act), as 
amended, for the elfin-woods warbler (Setophaga angelae), a bird 
species in Puerto Rico. This rule will add this species to the List of 
Endangered and Threatened Wildlife. We are also adopting a rule under 
the authority of section 4(d) of the Act (a ``4(d) rule'') that is 
necessary and advisable to provide for the conservation of the elfin-
woods warbler.

DATES: This rule is effective July 22, 2016.

ADDRESSES: This final rule is available on the Internet at http://www.regulations.gov and http://www.fws.gov/caribbean. Comments and 
materials we received, as well as supporting documentation we used in 
preparing this rule, are available for public inspection at http://www.regulations.gov. Comments, materials, and documentation that we 
considered in this rulemaking will be available by appointment, during 
normal business hours, at: U.S. Fish and Wildlife Service, Caribbean 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

FOR FURTHER INFORMATION CONTACT: Marelisa Rivera, Deputy Field 
Supervisor, U.S. Fish and Wildlife Service, Caribbean Ecological 
Services Field Office, P.O. Box 491, Road 301 Km. 5.1, Boquer[oacute]n, 
PR 00622; telephone 787-851-7297; facsimile 787-851-7440. Persons who 
use a telecommunications device for the deaf (TDD) may call the Federal 
Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Endangered Species Act, a 
species may warrant protection through listing if it is endangered or 
threatened throughout all or a significant portion of its range. 
Listing a species as an endangered or threatened species can only be 
completed by issuing a rule.
    This rule finalizes the listing of the elfin-woods warbler 
(Setophaga angelae) as a threatened species. It includes provisions 
under the authority of section 4(d) of the Act that are necessary and 
advisable for the conservation needs of the elfin-woods warbler.
    The basis for our action. Under the Act, we may determine that a 
species is a threatened species based on any of five factors: (A) The 
present or threatened destruction, modification, or curtailment of its 
habitat or range; (B) overutilization for commercial, recreational, 
scientific, or educational purposes; (C) disease or predation; (D) the 
inadequacy of existing regulatory mechanisms; or (E) other natural or 
manmade factors affecting its continued existence. We have determined 
that this species is currently at risk throughout all of its range due 
to threats related to habitat modification on private lands under 
agricultural and other land use requiring vegetation clearance (Factor 
A) and to other natural or manmade factors, such as restricted 
distribution and lack of connectivity, genetic drift, hurricanes, and 
the effects of climate change (Factor E).
    Under section 4(d) of the Act, the Secretary of the Interior has 
discretion to issue such regulations she deems necessary and advisable 
to provide for the conservation of the species. The Secretary also has 
the discretion to prohibit by regulation, with respect to a threatened 
species, any act prohibited by section 9(a)(1) of the Act.
    Habitats within some of the physically degraded private lands 
adjacent to elfin-woods warbler existing populations must be improved 
before they are suitable for the species; therefore, some activities 
that would normally be prohibited under 50 CFR 17.31 and 17.32 will 
contribute to the conservation of the elfin-woods warbler. For the 
elfin-woods warbler, the Service has determined that species-specific 
regulations authorized by section 4(d) of the Act are necessary and 
advisable to provide for the conservation of this species.
    Peer review and public comment. We sought comments from independent 
specialists to ensure that our determination is based on scientifically 
sound data, assumptions, and analyses. We invited these peer reviewers 
to comment on the listing proposal. We considered all comments and 
information we received during the comment period.

Previous Federal Action

    Please refer to the proposed listing rule (80 FR 58674, September 
30, 2015) for a detailed description of previous Federal actions 
concerning the elfin-woods warbler.

Summary of Comments and Recommendations

    In the proposed rule published on September 30, 2015 (80 FR 58674), 
we requested that all interested parties submit written comments on the 
proposal by November 30, 2015. We also contacted appropriate Federal 
and State agencies, scientific experts and organizations, and other 
interested parties and invited them to comment on the proposal. On 
October 3, 2015, we published a newspaper notice in the Primera Hora 
inviting general public comment. We did not receive any requests for a 
public hearing.

Peer Reviewer Comments

    In accordance with our peer review policy published on July 1, 1994 
(59 FR 34270), we solicited expert opinion from six knowledgeable 
individuals with scientific expertise that included familiarity with 
the elfin-woods warbler and its habitat, biological needs, and threats. 
We received responses from four of the peer reviewers.
    We reviewed all comments we received from the peer reviewers for 
substantive issues and new information regarding the listing of elfin-
woods warbler. The peer reviewers generally concurred with our methods 
and conclusions, and provided additional information, clarifications, 
and suggestions to improve this final rule. Substantive peer reviewer 
comments are addressed in the following summary

[[Page 40535]]

and incorporated into the final rule as appropriate.
    (1) Comment: One peer reviewer stated that the proposed listing 
rule did not include references to the Puerto Rico Breeding Bird Atlas 
Project of the Sociedad Ornitol[oacute]gica Puertorrique[ntilde]a, Inc. 
(SOPI; http://www.aosbirds.org/prbba/SpeciesEWWA.html). The peer 
reviewer noted there is one record of the elfin-woods warbler being 
detected during this project on March 31, 2005, in an area between 
Jayuya and Adjuntas (hexagon 913) in the central mountains of Puerto 
Rico by Bailey McKay and Richard West. The peer reviewer also indicated 
that during a Bicknell's thrush study conducted by the Vermont Center 
for Ecostudies between January and March, 2015, elfin-woods warblers 
were detected in the Maricao Commonwealth Forest (MCF) and El Yunque 
National Forest (EYNF), but were not detected in the Carite 
Commonwealth Forest (CCF) or in the municipalities of Jayuya and 
Adjuntas.
    Our Response: We appreciate these comments. We have added the new 
information regarding the observation of the elfin-woods warbler 
between Jayuya and Adjuntas to this final rule. The information 
available from the Web site provided by this reviewer classified this 
report as a possible observation of the elfin-woods warbler (identified 
with Code X (seen or heard within safe dates) in the database).
    (2) Comment: A peer reviewer provided information about a nest-
building activity by the elfin-woods warbler at the MCF recorded on May 
5, 2002. The peer reviewer also provided information about the location 
and description of the nest.
    Our Response: We appreciate this information, and have included the 
new nesting record in this final rule.
    (3) Comment: A peer reviewer stated that bird enthusiasts and 
wildlife photographers may pose a problem to the elfin-woods warbler, 
as some of them use recordings to attract these birds, probably 
altering their normal behavior. The peer reviewer indicated this 
situation appears to be increasing, and the existing regulations do not 
clearly address this potential harassment.
    Our Response: We appreciate this new information. At this time the 
Service does not have sufficient information to consider this action as 
a threat to the elfin-woods warbler. However, we will be monitoring the 
species and will keep track of the effect of these actions. When this 
final rule is effective (see DATES), regulations issued by the Service 
under the Act and by the Commonwealth of Puerto Rico under its laws 
will address actions that may result in take of the species.
    (4) Comment: One peer reviewer emphasized the need for research on 
the elfin-woods warbler and its status to inform managers and to 
facilitate the species' future delisting. He indicated that automated 
recording units (ARUs), which automatically record sounds for later 
computer analyses, suggest tremendous potential for surveying the more 
inaccessible sites in CCF, Toro Negro, and EYNF.
    Our Response: We acknowledge this comment and will develop recovery 
actions, including research needs, in the recovery plan for the 
species. The Service concurs with the peer reviewer on the use of ARUs 
to survey for the elfin-woods warbler in inaccessible sites. We have 
already initiated a project with academia and local nongovernmental 
organizations using ARUs to assess the presence of the elfin-woods 
warbler at the CCF and EYNF.
    (5) Comment: One peer reviewer made reference to the description of 
the elfin-woods warbler included in the proposed listing rule, 
indicating that adult and sub-adult elfin-woods warbler do not have a 
stripe above the eyes.
    Our Response: We appreciate this information. We described the 
elfin-woods warbler in the proposed listing rule based on Raffaele 1989 
(p. 168). However, considering the expertise of this peer reviewer on 
the elfin-woods warbler, we included this detailed information and 
specified that adult and sub-adult elfin-woods warbler do not have a 
stripe above the eyes.
    (6) Comment: One per reviewer indicated that the breeding season of 
the elfin-woods warbler should be extended to include the entire months 
of July and August because during these months the family groups stay 
together as a cohesive unit, which is essential for the survival of 
fledglings.
    Our Response: We concur with this rationale and have made changes 
to the ``Life History'' and 4(d) Rule sections of this final rule to 
reflect the peer reviewer's input.
    (7) Comment: A peer reviewer indicated that disturbances such as 
shade and coffee tree seasonal pruning and other activities described 
in the proposed 4(d) rule should be conducted from September 1 through 
February 28, which is the time period that the peer reviewer suggests 
is outside the breeding season of the elfin-woods warbler.
    Our Response: The proposed 4(d) rule that was published with the 
proposed listing rule indicated that coffee tree seasonal pruning and 
other activities would be conducted from July 1 through February 28. 
However, we concur with the information presented by the peer reviewer, 
and have made changes to this final rule to reflect the peer reviewer's 
input.
    (8) Comment: One peer reviewer warned about the potential of 
chemicals used for agriculture (such as pesticides, herbicides, and 
fertilizers) gaining access to the food chain and eventually to 
arthropods feeding birds such as the elfin-woods warbler.
    Our Response: Under the proposed and this final 4(d) rule, pest 
control substances (e.g., pesticides, herbicides) and fertilizers will 
be applied only twice a year during the establishment period of shade 
and coffee trees (i.e., the first 2 years). The Service believes that 
during this period, the structure of the agroforestry system is not 
mature enough to sustain the occurrence of elfin-woods warblers within 
these areas. Therefore, we do not expect that the elfin-woods warbler 
will be negatively affected by these actions.
    (9) Comment: A peer reviewer suggested modifying the following 
sentence in the Proposed Determination section: ``Current available 
information indicates that the elfin-woods warbler has a limited 
distribution, with only two known populations occurring within EYNF and 
MCF, including the private lands adjacent to MCF, and at least one 
extirpated population from CCF.'' The suggested modification is as 
follows: ``Current available information indicates that the elfin-woods 
warbler has a limited distribution, with only two known populations 
occurring within EYNF and MCF, including the private lands adjacent to 
MCF, and at least one possibly extirpated population from CCF.''
    Our Response: Based on the best available information, the elfin-
woods warbler appears to be extirpated from CCF. However, we do not 
discard the possibility that the species still occurs in this forest. 
Therefore, we accept the peer reviewer's comment and have modified this 
rule accordingly.

Federal Agency Comments

    Three of the peer reviewers consulted are also from Federal 
agencies. Only two provided peer review of the proposed rule, and their 
comments are addressed above under Peer Reviewer Comments. One 
additional Federal agency commented during the open comment period, but 
did not provide substantive information regarding the proposed listing.

[[Page 40536]]

Comments From the Commonwealth of Puerto Rico

    (10) Comment: One Commonwealth agency indicated it does not expect 
any significant impacts on the elfin-woods warbler as a result of the 
projects it conducts. However, the agency asked to be contacted should 
additional information on the habitat and location of the species 
become available in order to prevent potential impacts from future 
projects.
    Our Response: We appreciate these comments. Any new information 
about the species' distribution and habitat will be available to 
Commonwealth and Federal agencies via the Service's Environmental 
Conservation Online System (ECOS) Web site (http://ecos.fws.gov/ecp/) 
to be considered in future projects. For projects with a Federal nexus, 
consultations under section 7 of the Act address potential impacts to 
federally listed species.

Public Comments

    We received three public comments. While all indicated support for 
the listing of the elfin-woods warbler as a threatened species, none 
provided substantive comments requiring the Service's response.

Summary of Changes From the Proposed Rule

    Based upon our review of the comments from peer reviewers, other 
Federal and Commonwealth agencies, and the public, as summarized above, 
we reevaluated our proposed rule and incorporated the following changes 
into this final rule.
    (1) We modified the information in the species description to 
specify that adult and sub-adult elfin-woods warbler do not have a 
stripe above the eyes (see ``Species Description and Taxonomy,'' 
below).
    (2) We added information regarding the report of the elfin-woods 
warbler between the municipalities of Adjuntas and Jayuya as part of 
the species' range (see ``Historical and Current Distribution,'' 
below).
    (3) We modified the information regarding the breeding season of 
the elfin-woods warbler to include the entire months of July and August 
(see ``Life History,'' below).
    (4) We modified the provisions of the 4(d) rule to set forth that 
coffee tree seasonal pruning and other activities must be conducted 
from September 1 to February 28 (see 4(d) Rule, below).
    (5) We added information regarding an additional elfin-woods 
warbler's nest-building activity at the Maricao Commonwealth Forest 
(see ``Life History,'' below).

Background

Species Information

Species Description and Taxonomy
    The elfin-woods warbler was originally classified under the genus 
Dendroica, but is now recognized as Setophaga (Lovette et al. 2010, p. 
765). Angela and Cameron Kepler discovered the species in 1971, in the 
Dwarf forest type at El Yunque National Forest (EYNF) (Kepler and 
Parkes 1972, p. 3-5). The bird is about 12.5 centimeters (cm) (5 inches 
(in)) in length (Raffaele 1998, p. 406). The adult's upper body is 
predominantly black and white, with conspicuous white patches on the 
ear coverts and sides of the neck (Raffaele 1989, p. 168; Delannoy 
2015, pers. comm.). The elfin-woods warbler is often mistaken for the 
black and white warbler (Mniotilta varia), but the elfin-woods warbler 
is distinguished by its incomplete white eye-ring and entirely black 
crown. Immature elfin-woods warblers are similar to adults, except that 
they are grayish-green on the back, and yellowish-green on the head and 
underparts (Raffaele 1989, p. 168). The bird's call comprises a series 
of short, rapidly uttered, unmusical notes in one pitch, increasing in 
volume and ending with a short series of distinct double notes (Curson 
et al. 1994, p. 156).
Life History
    Little detailed information has been published on the life history 
of the elfin-woods warbler. Some authors noted that the elfin-woods 
warbler is an extremely active warbler, moving among the dense vines of 
forest strata with more foliage cover or smaller branch tips, foraging 
insects, usually at intermediate foliage heights of 3 to 15 meters (m) 
(10 to 50 feet (ft)) (Col[oacute]n-Merced 2013, p. 2). Opportunistic 
observations indicate the elfin-woods warbler feeds on moths, 
dragonflies, and other types of insects; however, its specific diet 
remains unknown (Col[oacute]n-Merced 2013, p. 2). Raffaele et al. 
(1998, p. 406) indicated that the breeding season of the species occurs 
from March to June. However, Delannoy (2015, pers. comm.) stated that 
based on available information (i.e., Delannoy 2009), the breeding 
season of the elfin-woods warbler should include the entire months of 
July and August because family groups stay together as a cohesive unit 
during May, June, July, and August. Delannoy (2009, p. 1) reported that 
four pairs of elfin-woods warblers banded between 2004 and 2008 
remained together in their territories in the Maricao Commonwealth 
Forest (MCF), suggesting that the species is monogamous. In addition, 
he reported that the elfin-woods warbler maintained territorial defense 
throughout the year and documented that calling activity increases from 
January to April and declines considerably during the time pairs are 
incubating eggs or brooding nestlings.
    Arroyo-V[aacute]zquez (1992, p. 363) reported the first detailed 
observation of two nests found in March and April of 1990 in aerial 
leaf litter at heights between 1.3 to 7.6 m (4.3 to 25 ft) and 
documented a clutch size of two to three eggs. Also, he observed that 
the pair's cup nest was woven from rootlets and fibers obtained from 
tree ferns and lined with grass leaves and down feathers. Raffaele et 
al. (1998, p. 406) further described the nest of the elfin-woods 
warbler as a compact cup, usually close to the trunk and well-hidden 
among epiphytes of a small tree. Salguero (2015, pers. comm.) indicated 
that on May 5, 2002, he and Carina Roig recorded a pair of elfin-woods 
warblers constructing a nest on a fork tip branch of a Pinus caribaea 
(Caribbean pine) about 5.0 m (16.4 ft) above ground at the former 
camping area near the MCF offices. Rodr[iacute]guez-Mojica (2004, p. 
22) reported the first nesting event inside a rotten tree stump of Palo 
Colorado (Cyrilla racemiflora) 7.0 m (23.3 ft) above ground in an 
abandoned camping area at the MCF. He described the nest structure as 
consisting of a tightly woven cup of fine plant fibers with dry leaves 
on its outside and noted that cavity-nesting is not common in warblers.
    Arroyo-V[aacute]zquez (1992, p. 363) and Rodr[iacute]guez-Mojica 
(2004, p. 22) suggested that the species selected aerial leaf litter 
and cavity-nesting sites to avoid predation. Some authors have 
suggested that elfin-woods warbler nest predators may include the 
pearly-eyed thrasher (Margarops fuscatus), Puerto Rican tanager 
(Nesospingus speculiferus), Puerto Rican screech owls (Megascops 
nudipes), Puerto Rican boa (Chilabothrus inornatus, listed as Epicrates 
inornatus), Puerto Rican racer (Alsophis portoricensis), and feral cats 
(Felis catus) (Delannoy 2009, p. 2). Other potential predators of 
immature and adult individuals include the Indian mongoose (Herpestes 
auropunctatus) and black rat (Rattus rattus) (Arroyo-V[aacute]zquez 
1992, p. 364).
Historical and Current Distribution
    The elfin-woods warbler is endemic to the island of Puerto Rico and 
was initially thought to occur only in the Luquillo Mountains at EYNF 
in eastern Puerto Rico (Kepler and Parks 1972, pp. 5-6; P[eacute]rez-
Rivera 1979, p. 58). During

[[Page 40537]]

the early 1970s, the species was reported in the MCF in western Puerto 
Rico (P[eacute]rez-Rivera 1979, p. 58; Cruz and Delannoy 1984, p. 92). 
In addition, the elfin-woods warbler was reported in the Toro Negro 
Commonwealth Forest in the Cordillera Central (central mountain range) 
(P[eacute]rez-Rivera 1979, p. 58), and in the area of Guavate in the 
Carite Commonwealth Forest in east-central Puerto Rico (P[eacute]rez-
Rivera and Maldonado 1977, p. 134). More recently, Miranda-Castro et 
al. (2000, pp. 119-123) and Anad[oacute]n-Irizarry (2006, p. 34) 
conducted elfin-woods warbler surveys in other forests of the 
Cordillera Central (i.e., Tres Picachos, Carite, Toro Negro, 
Sus[uacute]a, and Guilarte Commonwealth Forests, and Bosque del Pueblo 
in Adjuntas), but did not detect the species. However, on March 31, 
2005, Bailey McKay and Richard West recorded a possible observation of 
the elfin-woods warbler between the municipalities of Adjuntas and 
Jayuya while collecting breeding bird data for the Puerto Rico Breeding 
Bird Atlas Project (Salguero 2015, pers. comm.; SOPI 2005).
    Between 2011 and 2013, the Service, in collaboration with the 
Puerto Rican Ornithological Society, Inc., and BirdLife International, 
conducted a study using a habitat suitability model and a single-season 
occupancy modeling approach to assess the current geographic 
distribution of the elfin-woods warbler. The project included surveys 
between January and July during the species' breeding season within 
habitat currently occupied by the species in the MCF and predicted 
habitat within the Cordillera Central (Anad[oacute]n-Irizarry 2013, p. 
2). The predicted habitat included public and private lands within the 
municipalities of Jayuya, Ciales, Adjuntas, Ponce, Orocovis, and Juana 
D[iacute]az. The species was detected only in the MCF and adjacent 
private lands (Service 2014, p. 12).
    The elfin-woods warbler is particularly difficult to survey because 
of its small size, its constant moving behavior, and the dense 
vegetation of areas where it is found (Raffaele 1989, p. 168). In fact, 
Kepler and Parkes (1972, pp. 5-6) attribute the belated discovery of 
elfin-woods warbler to the above factors and their similarity to the 
black and white warbler. Even the vocalization of the elfin-woods 
warbler can be easily mistaken with other species. Although the 
presence of the elfin-woods warbler in the forests of the Cordillera 
Central of Puerto Rico cannot be disregarded based on the previous 
facts, the available information suggests that the current distribution 
of the species is now restricted to two populations in (1) EYNF and (2) 
MCF and adjacent private lands (Anad[oacute]n-Irizarry 2006, p. 5; 
Delannoy 2007, p. 4; Gonz[aacute]lez 2008, p. 19). The EYNF and the MCF 
are located about 150 kilometers (km) (93 miles (mi)) from each other 
(Arendt et al. 2013, p. 2). These habitats are considered essential to 
elfin-woods warbler abundance and are very important for maintaining 
healthy populations of the species (Delannoy 2007, p. 24), as they are 
the only currently known areas where the species still occurs. Although 
there is suitable habitat for the species between these two forests 
(Col[oacute]n-Merced 2013, p.51), the probability of dispersal for the 
species is low because EYNF is isolated from the central mountain range 
of Puerto Rico. Urban areas around EYNF increased by more than 2,000 
percent between 1936 and 1988, and continue to encroach on forested 
areas today (Thomlinson and Rivera 2000, p. 17). Between 1988 and 1993, 
urbanization around this forest increased by 31 percent and represented 
a 5 percent loss in vegetative cover, more than 80 percent of which was 
dense forest (Thomlinson and Rivera 2000, p. 17).
Habitat
    El Yunque National Forest--EYNF is located in the Sierra de 
Luquillo in eastern Puerto Rico and covers 11,310 hectares (ha) (28,000 
acres (ac)) of the island's area (Weaver 2012, p. 1). This forest was 
proclaimed as a Crown Reserve by Spain in 1876, and as a Forest Reserve 
by the U.S. Government since 1903. It is considered the oldest forest 
reserve and largest protected area in Puerto Rico, and is managed by 
the U.S. Forest Service (USFS). Elevations of this forest range from 
100 to 1,075 m (328 to 3,526 ft) and temperatures change with altitude, 
ranging between 23.5 and 27 degrees Celsius ([deg]C) (74 to 81 degrees 
Fahrenheit ([deg]F)) at the base of the mountain to between 17 and 20 
[deg]C (63 to 68 [deg]F) on the mountain peaks (Garc[iacute]a-
Martin[oacute] et al. 1996, p. 414). Mean annual rainfall ranges from 
approximately 245 cm/year (96 in/year) at lower elevations to 
approximately 400 cm/year (157 in/year) at higher elevations (Brown et 
al. 1983, p. 11). The EYNF contains five of the six Holdridge Life 
Zones found in Puerto Rico (Ewel and Whitmore 1973, pp. 32-49). These 
five zones are the lower montane wet forest, lower montane rain forest, 
subtropical moist forest, subtropical wet forest, and subtropical rain 
forest. In 1951, Wadsworth recognized four major forest types at EYNF: 
Dwarf, Palo Colorado, Tabonuco, and Sierra Palm (Anad[oacute]n-Irizarry 
2006, p. 9).
    At EYNF, the elfin-woods warbler was originally discovered in the 
Dwarf forest (Kepler and Parkes 1972, pp. 3-5). This forest type falls 
within the lower montane rain forest life zone (Ewel and Whitmore 1973, 
p. 49) and occupies 368 ha (909 ac) of EYNF (Weaver 2012, p. 5). It is 
found on exposed peaks with short, stunted vegetation above 900 m 
(2,952 ft) elevation (Weaver 2012, p. 58). In general, the Dwarf forest 
is not well populated with birds (Snyder et al. 1987, p. 61).
    Later, the species was documented at lower elevations in the Palo 
Colorado, Tabonuco, and Sierra Palm forests (Wiley and Bauer 1985, pp. 
12-18). The Palo Colorado forest occurs within the lower montane rain 
forest life zone, between approximately 600 and 900 m (1,968 and 2,952 
ft) (Weaver 2012, p. 1). This forest type covers about 3,441 ha (8,502 
ac) of the EYNF (Weaver 2012, p. 5). This forest is mainly composed of 
fast-growing trees with height not more than 24 m (78 ft) (Lugo 2005, 
p. 506).
    The Tabonuco forest is found between 150 and 600 m (492 and 1,968 
ft) elevation, and occupies 5,663 ha (13,993 ac) of the EYNF (Weaver 
2012, p. 5). This forest is dominated by the Tabonuco tree (Dacryodes 
excelsa), which grows primarily on the subtropical wet forest life 
zones (Ewel and Whitmore 1973, p. 32). The understory of this forest is 
sparsely vegetated, and the canopy is rich in aerial plants (e.g., 
bromeliads, orchids, vines, and arboreal ferns) (Ewel and Whitmore 
1973, p. 32).
    The Sierra Palm forest (also known as palm breaks) may reach canopy 
heights of 15 m (50 ft) with 17 cm (7 in) average diameters at breast 
height (dbh) and grows mainly on steep slopes at approximately 450 m 
(1,476 ft) elevation, covering about 1,838 ha (4,541 ac) of the EYNF 
(Weaver 2012, pp. 5 and 56). The Sierra Palm forest occurs on steep 
windward slopes and poorly drained riparian areas (Lugo 2005, p. 496). 
This forest is dominated by the Sierra palm (Prestoea montana) and 
occurs within the subtropical rain forest life zone (Ewel and Whitmore 
1973, p. 4).
    Maricao Commonwealth Forest and Adjacent Lands--The main population 
of the elfin-woods warbler in western Puerto Rico occurs within the 
MCF, located between the municipalities of Maricao, San Germ[aacute]n, 
Sabana Grande, and Mayag[uuml]ez (Ricart-Pujals and Padr[oacute]n-
V[eacute]lez 2010, p. 1). This forest is currently administered by the 
Puerto Rico Department of Natural and Environmental Resources (PRDNER)

[[Page 40538]]

and covers about 4,168 ha (10,543 ac) with elevations ranging between 
150 and 875 m (492 and 2,870 ft) above sea level. Annual average 
temperature is 21.7 [deg]C (71 [deg]F), and annual average rainfall is 
233 cm/year (92 in/year) (Silander et al. 1986, p. 210). Three of the 
six life zones reported for Puerto Rico occur on the MCF: Subtropical 
moist forest, subtropical wet forest, and lower montane wet forest 
(Ricart-Pujals and Padr[oacute]n-V[eacute]lez 2010, p. 8). The habitats 
where the elfin-woods warbler has been found within the MCF include 
Podocarpus Forest, Exposed Woodland Forest, Timber Plantations, and Dry 
Slopes Forest.
    The Podocarpus Forest occupies only 80 ha (197 ac) of the MCF and 
is located on the slopes and highest peaks (600-900 m (1,968-2,952 ft)) 
within the lower montane wet forest life zone (Department of Natural 
Resources (DNR) 1976, p. 185). Podocarpus Forest is dominated by 
Podocarpus coriaceus trees and has closed canopies and well-developed 
understories composed of tree ferns (Cyathea spp.), Sierra palms, and 
vines (Tossas and Delannoy 2001, pp. 47-53; Anad[oacute]n-Irizarry 
2006, p. 53; Gonz[aacute]lez 2008, pp. 15-16).
    The Exposed Woodland Forest occupies 2,711 ha (6,700 ac) of the MCF 
and is found in valleys, slopes, and shallow soils with a more or less 
continuous canopy (Gonz[aacute]lez 2008, pp. 15-16). These forest 
associations are found at elevations ranging from 470 to 800 m (1,542 
to 2,624 ft) within the subtropical wet forest life zone (DNR 1976, p. 
185).
    Timber Plantations occupy approximately 1,111 ha (2,745 ac) of the 
MCF in elevations ranging from 630 to 840 m (2,066 to 2,755 ft) within 
the subtropical wet forest and the subtropical moist forest life zones 
(DNR 1976, p. 185). This habitat--dominated by the Mar[iacute]a trees 
(Calophyllum calaba), eucalyptus (Eucalyptus robusta), and Caribbean 
pine (Pinus caribaea)--was planted in areas that were completely 
deforested for agriculture (Delannoy 2007, p. 9; Gonz[aacute]lez 2008 
p. 5).
    Dry Slopes Forest occupies approximately 1,367.3 ha (3,377 ac) of 
the MCF in elevations ranging from 120 to 300 m (394 to 984 ft) within 
the subtropical moist forest life zone (DNR 1976, p. 185). This habitat 
is found in shallow and excessively drained serpentine-derived soils 
dominated by xerophytic vegetation, thin trees, and a low open canopy. 
This forest type is more common in the southern and southeastern slopes 
of the MCF (DNR 1976, p. 185).
    Outside the MCF, the elfin-woods warbler has been detected within 
secondary forests and existing shade-grown coffee plantations 
(Gonz[aacute]lez 2008, pp. 15-16). Secondary forests are found at 
elevations ranging from 130 to 750 m (426 to 2,460 ft), and the shade-
grown coffee plantations are found at elevations ranging from 300 to 
600 m (984 to 1,968 ft) (Gonzalez 2008, p. 59; Puerto Rico Planning 
Board 2015). Also, the elfin-woods warbler has been documented at very 
low densities outside the MCF in pasturelands, Gallery forests, and 
rural residential areas, but not in sun-grown (unshaded) coffee 
plantations (Gonz[aacute]lez 2008, pp. 15-16). Young secondary forests 
developed as a result of abandonment of agriculture during the 20th 
century. These forests are less than 25 years old with an open canopy 
height of 12 to 15 m (40 to 50 ft) (Gonz[aacute]lez 2008, p. 6) and are 
found within the subtropical moist and subtropical wet forest life 
zones (DNR 1976, p. 185). Their understories are well-developed and 
dominated by grasses, vines, and other early-successional species 
(Gonz[aacute]lez 2008, p. 6). Mature secondary forests are over 25 
years old and develop on humid to very humid, moderate to steep slopes. 
They are characterized by their closed canopies, reaching heights of 20 
to 30 m (66 to 100 ft), and sparse to abundant understories 
(Gonz[aacute]lez 2008, p. 6). Some of these forests were used in the 
past for cultivation of shade-grown coffee and survived untouched 
because landowners abandoned agriculture activities (Delannoy 2007, p. 
10). The shade-grown coffee plantations are covered with tall mature 
forests dominated mostly by guaba (Inga vera) and guaraguao (Guarea 
guidonia) trees. Found on moderate to steep, humid mountain sides, 
these trees reach heights of 15 to 20 m (50 to 66 ft), and their 
understories constantly develop without grasses (Gonz[aacute]lez 2008, 
p. 6). Shade-grown coffee plantations are stable agro-ecosystems that 
provide habitat, nesting, and feeding for many native, endemic, and 
migratory species. Some of the best examples of this habitat are found 
in north, northwest, and northeast MCF (Delannoy 2007, p. 10). Studies 
have shown that biodiversity of plants, insects, reptiles, birds, and 
some mammals are higher in shade-grown than in sun-grown coffee 
plantations (Borkhataria et al. 2012, p. 165).
    Carite Commonwealth Forest--The Carite Commonwealth Forest (CCF) is 
within the known historical range of the elfin-woods warbler; however, 
the species was last observed in this forest about 15 years ago 
(P[eacute]rez-Rivera 2014, pers. comm.). The CCF has been managed for 
conservation by PRDNER since 1975 (DNR 1976, p. 169). This forest 
covers about 2,709 ha (6,695 ac), and ranges between 620 and 900 m 
(2,034 and 2,952 ft) in elevation (DNR 1976, p. 169). The CCF contains 
four forest types: Dwarf, Palo Colorado, Plantations, and Secondary 
(Silander et al. 1986, p. 188). These forest types are similar to the 
forests utilized by the elfin-woods warbler in EYNF and MCF.
    Although the elfin-woods warbler has not been recently observed in 
this forest (Anad[oacute]n-Irizarry 2006, p. 54; Anad[oacute]n-Irizarry 
2014, pers. comm.), the habitat suitability model developed for the 
species (Col[oacute]n-Merced 2013, p. 51) suggests CCF still provides 
suitable habitat for the species due to its similarity in elevation, 
climatic conditions, and vegetation associations with EYNF and MCF. The 
CCF's similarity to EYNF and MCF suggests that this forest could 
provide habitat for the expansion of the elfin-woods warbler's current 
range to maintain the species' historical, geographical, and ecological 
distribution.
Population Status
    El Yunque National Forest--Kepler and Parkes (1972, p. 15) 
estimated the elfin-woods warbler population at fewer than 300 pairs 
occurring in 450 ha (1,111 acres) at EYNF. Waide (1995, p. 9) reported 
an estimated population of 138 pairs in 329 ha (812 ac) in the Dwarf 
forest at EYNF. According to Anad[oacute]n-Irizarry (2006, p. 24), the 
species' mean abundance was highest (0.48 individuals (ind)/point 
count) in the Palo Colorado forest, slightly lower (0.42 ind/point 
count) in the Dwarf forest, lowest (0.01 ind/point count) in the 
Tabonuco forest, and none were recorded in Sierra Palm forest. Arendt 
et al. (2013, p. 8) conducted bird surveys approximately monthly from 
1989 to 2006, and reported a decline of the elfin-woods warbler 
population in EYNF over that period of 17 years. The species showed a 
significant general decline from 0.2 ind/ha to 0.02 ind/ha in the Dwarf 
forest, and from 1 ind/ha to 0.2 ind/ha in the Palo Colorado forest 
(Arendt et al. 2013, p. 9).
    Maricao Commonwealth Forest and Adjacent Lands--Cruz and Delannoy 
(1984, p. 92) suggested that the elfin-woods warbler was not uniformly 
distributed throughout the MCF and that it was found in different 
habitats within three studied sites. Anad[oacute]n-Irizarry (2006, p. 
27) conducted a survey from 2003 to 2004, in 102.4 ha (253 ac) of MCF 
and recorded 778 elfin-woods warblers in 18 counts for an average of

[[Page 40539]]

0.42 ind/ha/count. Gonz[aacute]lez (2008, pp. 23-28) reported the most 
recent population estimate for the elfin-woods warbler at the MCF and 
adjacent areas. Gonz[aacute]lez (2008, p. 18) estimated 97.67 elfin-
woods warbler individuals in an area of 203.2 ha (0.48 ind/ha) within 
the MCF. In areas adjacent to the MCF, he estimated 43.02 individuals 
in an area of 374.4 ha (0.11 ind/ha).
    Additionally, Gonz[aacute]lez (2008, p. 27) reported that the 
highest densities of elfin-woods warbler recorded per point-count 
stations in MCF were within the Podocarpus Forest (0.88 ind/ha). 
Moderate densities were recorded in Exposed Woodland (0.53 ind/ha), 
Timber Plantations (0.38 ind/ha), and Dry Slope Forest (0.06 ind/ha) 
(Gonz[aacute]lez 2008 p. 27). Gonz[aacute]lez (2008 p. 27) stated these 
results are similar to estimates obtained by previous studies in the 
same type of forests. In lands adjacent to the MCF, the shade-grown 
coffee plantations exhibited the highest elfin-woods warbler abundance 
(0.24 ind/ha) (Gonz[aacute]lez 2008, p. 24).
    Based on the studies mentioned above, in 2010, BirdLife 
International estimated the overall elfin-woods warbler population in 
Puerto Rico to be at least 1,800 mature individuals (Arendt et al. 
2013, p. 2).
    Carite Commonwealth Forest--In 1977, P[eacute]rez-Rivera and 
Maldonado (1977, p. 134) reported the species for the first time in the 
CCF. Two years later, P[eacute]rez-Rivera (1979, pp. 5-8) indicated 
that the species was more common than was expected when discovered. 
However, he mentioned that because the species appeared to be 
specialized to certain types of habitats, any kind of habitat 
disturbance or modification would cause a rapid decline of the species 
(P[eacute]rez-Rivera 1979, p. 58). The species was later recorded by 
P[eacute]rez-Rivera during the 1980s and 1990s in the following areas: 
Cerro La Santa, Camino El Seis, first recreation area near the forest 
entrance, private land near Barrio Farall[oacute]n, and Fincas Las 300 
(Delannoy 2007, pp. 22-23). Based on P[eacute]rez-Rivera's observations 
within these areas, the species seemed to be an uncommon and rare in 
CCF (i.e., 1 or 2 sightings every 10 visits) (Delannoy 2007, pp. 22-
23). The species was later detected occasionally by P[eacute]rez-Rivera 
within the same areas until it was last observed by him more than 15 
years ago (P[eacute]rez-Rivera 2014, pers. comm.).
    The surveys conducted by Anad[oacute]n-Irizarry between 2003 and 
2004, and between 2012 and 2013, failed to detect the species within 
the CCF. The study conducted during the period of 2003-2004 
(Anad[oacute]n-Irizarry 2006, p. 54) included traditional areas 
previously searched by P[eacute]rez-Rivera, and the surveys were 
conducted along 5.0 km (3.1 mi) of existing trails. The most recent 
surveys, conducted between 2012 and 2013, avoided the use of existing 
trails and included nontraditional areas, but they also failed to 
detect the species (Anad[oacute]n-Irizarry 2014, pers. comm.). However, 
during these surveys, the amount of surveyed area within nontraditional 
habitat was not significant (i.e., 15 survey stations).
    Although these studies failed to detect the species, Anad[oacute]n-
Irizarry (2006, p. 54; 2014, pers. comm.) suggested the possibility 
that the species is still present in isolated pockets of forest that 
were not searched during the studies (Delannoy 2007, p. 22). The 
apparent persistent and relatively sedentary behavior of this species 
to inhabit certain small and isolated pockets of the forest might have 
led these authors to suggest that it is possible that CCF may harbor 
undetected elfin-woods warblers (Anad[oacute]n-Irizarry 2006, p. 54; 
Delannoy 2007, pp. 22-23; P[eacute]rez-Rivera 2014, pers. comm.). 
Anad[oacute]n-Irizarry (2006, p. 54), Delannoy (2007, pp. 22-23), and 
P[eacute]rez-Rivera (2014, pers. comm.) have suggested that the species 
was extirpated from the traditional areas searched by them during the 
1980s, 1990s, and between 2003 and 2004 due to habitat modification 
activities (i.e., transmission antenna development and road 
development) that occurred in those years. If this is the case, a 
comprehensive assessment of the status of this population would require 
extensive searches covering a much larger area into the fragmented 
landscape of the CCF (Delannoy 2007, pp. 22-23). Therefore, during 
early 2016 the Service contracted for a survey to include traditional 
and nontraditional areas within and beyond CCF's boundaries. A total of 
60 sites were surveyed between March and April 2016 using ARBIMON 
portable recorders (Aide and Campos 2016). Surveyed areas also included 
suitable habitat identified by the habitat suitability model developed 
by Col[oacute]n-Merced (2013). None of the 23,944 1-minute recordings 
analyzed for the presence of the elfin-woods warbler resulted in 
positive detection, indicating the species is not present in CCF (Aide 
and Campos 2016).

Summary of Factors Affecting the Species

    Section 4 of the Act, and its implementing regulations at 50 CFR 
part 424, set forth the procedures for adding species to the Federal 
Lists of Endangered and Threatened Wildlife and Plants. Under section 
4(a)(1) of the Act, we may list a species based on:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    Listing actions may be warranted based on any of the above threat 
factors, singly or in combination.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of Its Habitat or Range

    The majority of extant elfin-woods warbler populations are 
restricted to two disjunct primary habitats in montane forests at EYNF 
and at MCF and private lands adjacent to MCF. Although the elfin-woods 
warbler has not been recently observed in CCF, this forest and adjacent 
lands still contains suitable habitat for the species. The elfin-woods 
warbler needs suitable forested habitats for essential behaviors such 
as foraging, breeding, and sheltering (Anad[oacute]n-Irizarry 2006, pp. 
5-8).
    In the past, the majority of the forested areas in Puerto Rico--
EYNF, MCF, and CCF--were impacted by agricultural practices; extraction 
of timber for construction and charcoal (Dominguez-Cristobal 2000, pp. 
370-373; Dominguez-Cristobal 2008, pp. 100-103); development of 
infrastructure for utilities and communications; and construction of 
roads, recreational facilities, and trails, negatively affecting elfin-
woods warbler habitat (DNR 1976, p. 169; Waide 1995, p. 17; Delannoy 
2007, p. 4; Anad[oacute]n-Irizarry 2006, p. 28; P[eacute]rez-Rivera 
2014, pers. comm.). Currently, each agency manages these forests for 
conservation purposes under its authorities and mandates to promote 
habitat conservation (see Factor D. The Inadequacy of Existing 
Regulatory Mechanisms, below); habitat modification pressures from 
agriculture practices and the development of new infrastructure within 
the forests are currently very low. However, typical forest management 
of existing disturbed areas (e.g., trail maintenance, road maintenance, 
transmission antenna maintenance, and recreational facility 
improvements) and research activities (e.g., species surveys, 
endangered species reintroductions) still occur within these forests. 
The maintenance performed on roads, trails, transmission antenna 
facilities, and recreational

[[Page 40540]]

facilities is not presently affecting elfin-woods warbler habitat 
within these forests. When a management or research activity is 
conducted, both USFS and PRDNER closely coordinate with the Service 
during design and planning stages. These planning efforts minimize 
possible adverse effects on the species and its habitat. In contrast, 
the expansion of existing facilities (i.e., transmission antennas, 
access roads, access gates, administration buildings, utilities) within 
the forests is still a possibility and may result in the degradation of 
suitable habitat of elfin-woods warbler.
    Although the threats to the species and its habitat have been 
minimized within the lands managed and administrated by USFS and PRDNER 
within EYNF, MCF, and CCF, respectively, the species is still also 
threatened with habitat destruction, fragmentation, and degradation in 
15 percent of its suitable occupied habitat within private lands 
adjacent to MCF. These private lands are known to be susceptible to 
habitat modification caused by unsustainable agricultural practices and 
other land uses requiring vegetation clearance (e.g., deforestation, 
monoculture of minor fruits, livestock related activities, human-
induced fires, residential use, road improvements). Although not known 
to be currently occupied, the areas outside EYNF and CCF are also 
vulnerable to these threats because they are not within the protected 
lands. In the Municipality of Maricao, the Puerto Rico Department of 
Agriculture (PRDA) has identified 301 properties (8,442 acres) with 
potential to be developed as agricultural lands for coffee and citrus 
plantations (Resoluci[oacute]n Conjunta del Senado 2014, p. 2). 
Although the conversion of forested areas to sun-grown coffee 
plantations is still occurring on private lands adjacent to MCF, the 
magnitude of this activity is localized and at a lower level than it 
was in the past. However, PRDA has expressed its intention to increase 
the acreages of coffee plantations in Puerto Rico to 16,000 acres by 
2016 (PRDA 2015, no page number). PRDA's goal is to provide incentives 
to landowners (i.e., $1,300/acre) for the establishment of new planting 
areas of sun-grown or partially shaded coffee (i.e., 1,000 coffee trees 
per acre) (Regulation 6372, p. 3-6; Regulation Governing the Incentives 
Programs of the Coffee Production Industry in Puerto Rico). Some of 
these areas, previously used for agriculture, were abandoned and are 
currently forested. The majority of the sun-grown coffee plantations 
were converted several decades ago, resulting in the elimination of 
native forest, thus reducing the habitat value for wildlife, including 
the elfin-woods warbler (Delannoy 2007, p. 20). The most recent studies 
conducted in MCF and adjacent lands (i.e., Delannoy 2007, p. 15; 
Gonz[aacute]lez 2008, p. 59) did not detect elfin-woods warblers in 
sun-grown coffee plantations on privately owned lands adjacent to the 
forest. The establishment of a sun-grown coffee plantation requires the 
deforestation of the area, removing habitat that elfin-woods warblers 
are or could be using.
    The increase of urban development in private lands adjacent to EYNF 
and CCF has negatively affected elfin-woods warbler suitable habitat 
around these forests. Gould et al. (2007, pp. 29-31) suggested there is 
an increasing urbanization trend of the limited land area of eastern 
Puerto Rico where these forests are located. Urban development in this 
region increased more than 15 percent between 1991 and 2003 (Gould et 
al. 2007, pp. 29-31). Martinuzzi et al. (2007, pp. 294-296) reported 
that almost 52 percent of the island is classified under either 
``Urban'' use (i.e., 16 percent; 142,562 ha) or ``Densely Populated 
Rural'' use (i.e., 36 percent; 320,219 ha) classes. The Urban-use class 
enhances the contiguity between the compact urban areas across the 
island, and gives an accurate view of how an ``urban ring'' encircles 
interior mountainous and protected areas like EYNF and CCF (Martinuzzi 
et al. 2007, p. 294). The Densely Populated Rural-use class surrounds 
the urban-use areas and represents most of the territory where human 
developments expand out from the urban centers following secondary 
routes (Martinuzzi et al. 2007, p. 294). Although the most evident 
land-use changes in the last 25 years have been the intensification of 
urbanization that surrounds these forests (Helmer 2004, pp. 33-35, 
Gould et al. 2007, pp. 29-31, Martinuzzi et al. 2007, p. 294), it is 
not known how much of these lands currently contain habitat suitable 
for the elfin-woods warbler.
Conservation Efforts To Reduce the Present or Threatened Destruction, 
Modification, or Curtailment of Its Habitat or Range
    In 2014, the Service developed a candidate conservation agreement 
(CCA) with USFS and PRDNER to promote the conservation of the elfin-
woods warbler. The purpose of the CCA is to implement measures to 
conserve, restore, and improve the elfin-woods warbler's habitat and 
populations within EYNF and MCF (Service 2014, p. 6). The CCA provides 
that PRDNER and USFS will promote, develop, and implement the best 
management practices to avoid any potential threat to suitable and 
occupied elfin-wood warbler habitat and populations. It also provides 
that both agencies will implement restoration and habitat enhancement 
efforts within degraded areas of EYNF and MCF. The agencies will also 
(1) determine the habitat use, movement, and activity patterns of the 
species; (2) design and establish long-term population monitoring 
programs; and (3) develop outreach and education programs to improve 
mechanisms to promote habitat conservation and restoration within 
private lands adjacent to both forests.
    Although the elfin-woods warbler also occurs on privately owned 
lands adjacent to MCF that are not covered by the CCA, these areas are 
part of a habitat restoration initiative in southwestern Puerto Rico 
implemented by the Service since 2010, through the Partners for Fish 
and Wildlife (PFW) and Coastal (CP) Programs. The PFW and CP are 
voluntary programs that provide technical and financial assistance to 
landowners to implement restoration and conservation practices on their 
lands for a particular amount of time. These programs promote the 
restoration of degraded habitat that was likely occupied by the species 
before the conversion to agricultural lands and that may be restored as 
suitable elfin-woods warbler habitat in the future. In some cases, 
occupied suitable habitat for the species is enhanced and protected 
through cooperative agreements with the private landowners.
    Between 2010 and 2014, a total of 522 ha (1,290 acres) of degraded 
tropical upland forest and 21 km (13 miles) of riparian buffers have 
been restored and conserved through these programs in collaboration 
with the Natural Resources Conservation Service (NRCS), Farm Service 
Agency (FSA), PRDNER, Envirosurvey Inc. (a local nongovernmental 
organization), and other partners. Although this initiative promotes 
the restoration and enhancement of degraded habitat adjacent to the MCF 
and may potentially provide suitable habitat for the elfin-woods 
warbler, challenges such as limited resources and uncertainty about 
landowner participation may affect the implementation of management 
practices that mitigate impacts of agricultural practices.
Summary of Factor A
    The elfin-woods warbler's restricted distribution makes it 
vulnerable to habitat destruction and modification.

[[Page 40541]]

The majority of extant elfin-woods warbler populations occur on public 
lands managed for conservation purposes where activities that may 
affect the species or its habitat are regulated, and measures to 
minimize or avoid those impacts are being implemented based on 
management plans or agencies' management mandates. The elfin-woods 
warbler has been reported on private lands only outside MCF. Private 
lands adjacent to EYNF have not been surveyed, and recent surveys 
conducted within the CCF and adjacent private lands did not detect the 
elfin-woods warbler (Aide and Campos 2016). Nonetheless, the 
agricultural activities and development projects on private lands 
adjacent to EYNF, MCF, and CCF may result in the loss or fragmentation 
of habitat that may be suitable for the species as has been suggested 
by some researchers. Therefore, we believe that habitat curtailment or 
modification is a threat to the elfin-woods warbler.

Factor B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    Based on the available information, overutilization has not been 
documented as a threat to the elfin-woods warbler.

Factor C. Disease or Predation

    Delannoy (2009, p. 2) indicated that the Puerto Rican sharp-shinned 
hawk (Accipiter striatus venator) infrequently preys on the elfin-woods 
warbler. Other potential elfin-woods warbler nest predators may include 
the pearly-eyed thrasher, Puerto Rican tanager, Puerto Rican screech 
owl, Puerto Rican boa, Puerto Rican racer, and feral cat (Delannoy 
2009, p. 2). Additionally, Arroyo-V[aacute]zquez (1992, p. 364) noted 
that the Indian mongoose and black rat are potential egg and nestling 
predators. Nonetheless, we are not aware of any scientific or 
commercial information that predation of elfin-woods warblers is having 
an adverse effect on the species, and therefore we believe that 
predation is not a threat to the elfin-woods warbler. Similarly, we 
have no evidence of any disease affecting the species.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    In 1999, the Commonwealth of Puerto Rico approved Law No. 241-1999, 
known as the New Wildlife Law of Puerto Rico (Nueva Ley de Vida 
Silvestre de Puerto Rico). The purpose of this law is to, among other 
things, protect, conserve, and enhance both native and migratory 
wildlife species; declare as property of Puerto Rico all wildlife 
species within its jurisdiction; issue permits; regulate hunting 
activities; and regulate exotic species. In 2004, the Commonwealth of 
Puerto Rico approved the Regulation Governing the Management of 
Vulnerable and Endangered Species on the Commonwealth of Puerto Rico 
(Regulation 6766; Reglamento para Regir el Manejo de las Especies 
Vulnerables y en Peligro de Extinci[oacute]n en el Estado Libre 
Asociado de Puerto Rico). Regulation 6766 prohibits collecting, 
killing, or harming species listed under Territorial law, as well as 
possessing, transporting, or selling items derived from listed species, 
and requires authorization from the PRDNER Secretary for any action 
that may affect designated critical habitat of listed species under 
this regulation (Departamento de Recursos Naturales y Ambientales 2004, 
pp. 9, 18). In 2004, the Commonwealth of Puerto Rico included the 
elfin-woods warbler in Regulation 6766 as a ``vulnerable species'' (a 
species that, although is not listed as endangered or critically 
endangered, faces a high risk of extinction in a foreseeable future).
    In addition to laws that specifically protect the elfin-woods 
warbler, MCF and CCF are protected under Puerto Rico's Forests Law (Law 
No. 133-1975; Ley de Bosques de Puerto Rico), as amended in 2000, which 
prohibits causing damage to and collection of flora and fauna in public 
forests. Moreover, all Commonwealth forests are designated as Critical 
Wildlife Areas (CWA) by PRDNER. The CWA designation constitutes a 
special recognition by this agency with the purpose of providing 
information to other Commonwealth and Federal agencies about the 
conservation needs of these areas, and assisting permitting agencies in 
precluding negative impacts as a result of permit approvals or 
endorsements (PRDNER 2005, p. 6).
    The Migratory Bird Treaty Act (MBTA) (16 U.S.C. 703-712) provides 
protection for the elfin-woods warbler, which is defined as a migratory 
bird under the MBTA. The MBTA makes it unlawful to pursue; hunt; take; 
capture; kill; attempt to take, capture, or kill; possess; offer for 
sale; sell; offer to barter; barter; offer to purchase; purchase; 
deliver for shipment; ship; export; import; cause to be shipped, 
exported, or imported; deliver for transportation; transport or cause 
to be transported; carry or cause to be carried; or receive for 
shipment, transportation, carriage, or export, any migratory bird, or 
any part, nest, or egg of such bird, or any product, whether or not 
manufactured, which consists of, or is comprised in whole or part, of 
any such bird, or any part, nest, or egg thereof. However, no 
provisions in the MBTA prevent habitat destruction unless direct 
mortality or destruction of active nests occurs.
    Finally, the elfin-woods warbler co-occurs with other species that 
are listed under the Act. In the EYNF, the species co-occurs with the 
Puerto Rican sharp-shinned hawk (Accipiter striatus venator), Puerto 
Rican boa, Puerto Rican broad-winged hawk (Buteo platypterus 
brunnescens), Puerto Rican parrot (Amazona vittata), and several 
federally listed plants: Styrax portoricensis, uvillo (Eugenia 
haematocarpa), Lepanthes eltoroensis, chupacallos (Pleodendron 
macranthum), capa rosa (Callicarpa ampla), palo colorado (Ternstroemia 
luquillensis), Ternstroemia subsessilis, and Ilex sintenisii. In the 
MCF, the species co-occurs with the Puerto Rican sharp-shinned hawk, 
Puerto Rican boa, and several federally listed plants: Cranichis 
ricartii, Gesneria pauciflora, palo de rosa (Ottoschulzia rhodoxylon), 
palo colorado (Ternstroemia luquillensis), higuero de sierra 
(Crescentia portoricensis), and Cordia bellonis. Because of the 
occurrence of these federally listed species within the same habitat 
where the elfin-woods warblers occurs, any Federal action, funding, or 
permit within these forests or in private lands adjacent to these 
forests that may affect these listed species requires a section 7 
consultation under the Act. Therefore, the elfin-woods warbler may 
benefit from indirect protection of these listed species (i.e., 
implementation of habitat restoration practices and habitat 
protection).
Summary of Factor D
    Based on the information currently available to us, the Federal and 
Commonwealth regulatory mechanisms are being implemented and are 
functioning as designed. Lack of enforcement of these laws and 
regulations has not been identified as having a negative impact to the 
species or exacerbating other negative effects to the species. 
Therefore, we do not find existing regulations to be inadequate.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

Hurricanes and the Effects of Climate Change
    The geographic location of islands in the Caribbean Sea makes them 
prone to hurricane impacts (Wiley and Wunderle 1993, p. 320). In fact, 
the frequency of hurricane occurrences is higher in the

[[Page 40542]]

southeastern United States and the Caribbean than other regions of the 
world (Wiley and Wunderle 1993, p. 320). Hurricanes can have both 
direct and indirect effects on bird populations, which may determine 
the characteristics of local avifauna (Wauer and Wunderle 1992, p. 656; 
Wunderle et al. 1992, p. 323). Arendt et al. (2013, p. 2) suggested 
that catastrophic weather events such as hurricanes can negatively 
affect the elfin-woods warbler due to its restricted distribution and 
low number of individuals. Some species may cope with hurricane-induced 
changes by selecting different prey items, while others may switch 
their foraging behavior and locations (Wauer and Wunderle 1992, p. 657; 
Wunderle et al. 1992, pp. 323-326).
    The frequency of hurricane-induced damage equivalent to F3 (severe) 
on the Fujita scale (Fujita 1971) is at least three times greater in 
the northeastern quadrant of Puerto Rico, where EYNF and CCF are 
located, compared to the rest of the island (White et al. 2014, p. 30). 
In contrast, the western side of Puerto Rico, where MCF is located, is 
subject to different hurricane trajectories and risks than the eastern 
portion of the island (White et al. 2010, p. 16). For example, in 1998, 
Hurricane Georges struck MCF, which previously had been spared from 
hurricanes since 1932 (Tossas 2006, p. 81). Hence, studies of the 
effects of hurricanes on bird populations in Puerto Rico are limited to 
the northeastern region and little is known about how bird species are 
affected elsewhere on the island (Tossas 2006, p. 81).
    Delannoy (2007, p. 24) suggested that elfin-woods warbler 
populations at MCF appeared to be stable. However, studies conducted 
from 1989 to 2006 at EYNF documented a declining trend in the elfin-
woods warbler population during the study period (Arendt et al. 2013, 
pp. 8-9). Arendt et al. (2013, p. 8) stated that this documented 
downward population trend could be related to intrinsic causes (e.g., 
physiological, genetic). Nonetheless, they further suggest that it is 
more likely that natural habitat conversion and degradation, resulting 
from cyclonic events, are playing an important role in the species' 
decline at EYNF. Direct effects of hurricanes on habitat include 
massive defoliation, snapped and wind-thrown trees, massive tree 
mortality, and landslides (Lugo 2008, p. 368). For example, Hurricane 
Hugo (1989) and Hurricane Georges (1998) caused extensive damage in 
EYNF, which damage may have adversely impacted the elfin-woods 
warbler's primary habitat (Arendt et al. 2013, pp. 8-9). Arroyo (1991, 
p. 55) noted that the species was not recorded during 1990 from areas 
it was reported from previously at EYNF. This forest was heavily 
damaged by Hurricane Hugo, with more than 80 percent of the forest 
completely defoliated (Boucher 1990, p. 164). In contrast, at the MCF, 
Arroyo (1991, pp. 55-56) recorded an apparent vertical migration 
pattern of the species during months of heaviest rains. Moreover, 
Tossas (2006, p. 84) found that the elfin-woods warbler was one of two 
species that recovered within a year to pre-hurricane population levels 
after Hurricane Georges. This finding suggested that warblers abandoned 
defoliated sites immediately after the hurricane and shifted to 
protected patches with adequate foraging substrate and prey until the 
defoliated sites recovered (Tossas 2006, p. 84). Arendt et al. (2013, 
p. 9) indicated that these contrasting findings may be the result of 
disproportionate damage caused by storms in the respective forests. 
Moreover, the landscape at EYNF is different from that of the MCF in 
that at EYNF there is no continuous forested vegetation beyond the 
forest boundaries mainly due to conversion of agricultural lands and 
lowland broadleaf forests to urbanized areas (Lugo et al. 2004, p. 29). 
Therefore, the probability of dispersion to undamaged areas within and 
outside EYNF could be reduced for the elfin-woods warbler depending on 
the damages to the vegetation. The lack of suitable habitat around the 
EYNF also reduces the probability of elfin-woods warbler re-
colonization from the MCF, which is 150 km (93 mi) away (Arendt et al. 
2013, p. 2).
    As discussed above, Anad[oacute]n-Irizarry (2006, p. 54), Delannoy 
(2007, p. 24), and Anad[oacute]n-Irizarry (2014, pers. comm.) have 
suggested the elfin-woods warbler no longer exists within CCF. 
P[eacute]rez-Rivera (2014, pers. comm.) has suggested that the habitat 
modification caused by Hurricane Hugo and Hurricane Georges at CCF may 
have had a negative effect on the elfin-woods warbler. However, he 
acknowledged that before concluding the species was extirpated from the 
forest due to these climatological events, a formal and extensive 
survey should be conducted to include nontraditional areas within and 
outside of CCF (P[eacute]rez-Rivera 2014, pers. comm.). He suggested 
hurricanes might be detrimental to low densities and habitat-
specialized species, but at the same time might benefit insectivorous 
species like the elfin-woods warbler. In 1989, a month after Hurricane 
Hugo, P[eacute]rez-Rivera (1991, pp. 474-475) recorded the Antillean 
euphonia (Euphonia musica) shifting its feeding and foraging behavior 
in CCF as a result of the habitat disturbance following the hurricane. 
Some authors (i.e., Wauer and Wunderle 1992, p. 657; Wunderle et al. 
1992, pp. 323-326) have suggested that the frequency of hurricanes in 
the Caribbean may be determining some of the characteristics of the 
local avifauna, such as the shifting into new habitats due to 
hurricane-induced changes.
    Hurricanes can have positive effects on forest and bird ecology by 
temporarily increasing forest productivity (Wiley and Wunderle 1993, p. 
337), particularly for species with ample distribution (White et al. 
2014, p. 31). However, the immediate negative effects of these powerful 
atmospheric events for a species with demographically vulnerable 
populations, such as the elfin-woods warbler, outweigh the benefits 
accrued via short-term primary productivity of vegetation (White et al. 
2014, p. 31). This might explain the declining elfin-woods warbler 
population trend documented by Arendt et al. (2013, pp. 8-9) at EYNF.
    Studies predict an increase in hurricane intensity in the Atlantic, 
with higher wind speeds and greater amounts of precipitation, but a 
reduction in the overall number of storms (Jennings et al. 2014, p. 8). 
As mentioned above, hurricanes may result in direct negative effects to 
the species and its habitat.
    Based on the above information, it is possible that the elfin-woods 
warbler could experience local extinction due to these catastrophic 
weather events. While the species appears to have the ability to 
temporarily move to undisturbed areas and survive in MCF, such 
dispersal ability has not been documented at EYNF. Having two 
geographically separate populations on both ends of Puerto Rico may 
benefit the elfin-woods warbler since, based on the history of 
hurricanes striking the island, it is unlikely for both EYNF and MCF to 
be impacted by the same weather system at once. However, the fact that 
there are only two known populations left makes the species more 
vulnerable to extinction if one is lost due to a catastrophic weather 
event. It is important to note, however, that there are no specific 
studies corroborating hurricanes as a main cause of elfin-woods warbler 
population declines at EYNF and MCF, nor that hurricanes caused the 
apparent extirpation of the species from CCF.
    Regarding climate, general long-term changes have been observed, 
including changes in amount of precipitation, wind patterns, and 
extreme weather

[[Page 40543]]

events (e.g., droughts, heavy precipitation, heat waves, and the 
intensity of tropical cyclones) (Intergovernmental Panel on Climate 
Change (IPCC) 2007, p. 30). For example, projected decreases in 
precipitation in the Caribbean suggest drier wet seasons, and even 
drier dry seasons (Jennings et al. 2014, p. 1).
    As previously mentioned, the elfin-woods warbler is currently known 
only from specific habitat types at EYNF and MCF, which makes the 
species susceptible to the effects of climate change. It has been 
stated that higher temperatures, changes in precipitation patterns, and 
any alteration in cloud cover will affect plant communities and 
ecosystem processes in EYNF (Lasso and Ackerman 2003, pp. 101-102). In 
fact, the distribution of tropical forest life zones in the Caribbean 
is expected to be altered due to both intensified extreme weather 
events and progressively drier summer months (Wunderle and Arendt 2011, 
p. 44). At EYNF, such alteration may allow low-elevation Tabonuco 
forest species to colonize areas currently occupied by Palo Colorado 
forest (Scatena and Lugo1998, p. 196). Dwarf forests at EYNF also are 
very sensitive to the effects of climate change because of their 
occurrence in narrowly defined environmental conditions (Lasso and 
Ackerman 2003, p. 95). Dwarf forest epiphytes may experience moisture 
stress due to higher temperatures and less cloud cover with a rising 
cloud base, affecting epiphyte growth and flowering (Nadkarni and 
Solano 2002, p. 584). As previously mentioned, both the Palo Colorado 
and Dwarf forests have been reported to have the highest elfin-woods 
warbler mean abundance (Anad[oacute]n-Irizarry 2006, p. 24). Although 
the available information predicting changes in habitat due to the 
effects of climate change pertains to EYNF, similar changes would be 
expected for the MCF and CCF, which lies within two of the same life 
zones as EYNF.
    As indicated above, such climate changes are likely to alter the 
structure and distribution of the habitat used by the elfin-woods 
warbler. According to Arendt et al. (2013, p. 9), approximately 50 
percent of the Caribbean birds show medium to high vulnerability to the 
effects of climate change. Based on that information, species that are 
dependent on specific habitat types, and that have limited distribution 
or have become restricted in their range, like the elfin-woods warbler, 
will be most susceptible to the effects of climate change. However, 
while continued change is expected, the magnitude and rate of that 
change is unknown in many cases. In tropical and subtropical forests, 
significant knowledge gaps exist in predicting the response of natural 
systems to the effects of climate change, and uncertainties exist with 
studies forecasting trends in climate (Jennings et al. 2014, p. 33). 
Moreover, regionally downscaled climate models projecting temperature 
and precipitation patterns at fine scales are not readily available for 
locations within the Caribbean region, including Puerto Rico (Jennings 
et al. 2014, p. 33). While existing large-scale global climate models 
are useful in determining potential future trends (Angeles et al. 2007, 
p. 556), the lack of fine-scale data in Puerto Rico's mountainous 
regions is especially troublesome, as variations in climate with 
elevation over short horizontal distances cannot be captured by 
existing climate models, especially in predictions of extreme events 
(Meehl et al. 2007, p. 477).
Human-Induced Fires
    Fires are not part of the natural processes for subtropical and 
moist forests in Puerto Rico (Santiago-Garcia et al. 2008, p. 604). In 
fact, M[eacute]ndez-Tejeda et al. (2015, p. 363) concluded that the 
majority of forests fires in Puerto Rico are produced by human actions. 
However, as annual rainfall decreases over time in the Caribbean 
region, longer periods of drought are expected in the future (Breshears 
et al. 2005, pp. 146-147; Larsen 2000, pp. 510-512). In 2000, Flannigan 
et al. (2000, pp. 225-226) projected an increase of the global fire 
occurrence over the next century due to the effects of climate change. 
In Puerto Rico, historical evidence suggests fire frequency is 
increasing (Burney et al. 1994, p. 277; Robbins et al. 2008, pp. 530-
531). Moreover, the interactions between climate warming and drying, 
and increased human development, are considered to have the potential 
to increase the effects of fires (Robbins et al. 2008, pp. 530-531).
    In EYNF, CCF, and adjacent lands, fires are not considered common. 
The tropical rain and moist forest conditions of EYNF and CCF (i.e., 
average annual rainfall of 304.8 cm (120 in) or more) and the very high 
humidity during most of the year are not conditions conducive to fires 
as they are in the dry, temperate climates encountered in other 
regions. The last fire incident in EYNF, recorded in 1994, was 
categorized as a ``minimal fire'' that was quickly controlled by USFS 
staff (USFS 2015, no page number). In the CCF area, fires are 
considered human-induced and occur in a low frequency along the road 
PR-184 (Monsegur 2015, pers. comm.). Although the road-side fires are 
considered minimal, they have the potential to extend to forested lands 
within CCF and adjacent private lands affecting suitable elfin-woods 
warbler habitat.
    In the Maricao area (i.e., Municipalities of Sabana Grande and San 
Germ[aacute]n), fires occur more frequently on the southern dry slopes 
of MCF and adjacent private lands, particularly during the dry season 
(Avila 2014, pers. comm.). Human-induced fires modify the landscape and 
ecological conditions of the habitat by promoting growth of nonnative 
trees and grasses (Brandeis and Woodall 2008, p. 557). These landscape 
modifications may reduce the quality and quantity of potential elfin-
woods warbler habitat. Moreover, these fires alter the habitat, 
decreasing the ability of the species to disperse to other forested 
habitats. Although the primary habitat for the species in MCF (i.e., 
Podocarpus forest) (Gonz[aacute]lez 2008, pp. 20-21) is not prone to 
fire disturbance because it is located on the highest peaks within the 
lower montane wet forest life zone, suitable habitat at lower 
elevations might be in danger if these fires extend to forested lands 
within the forest or private lands. Severe fires in moist tropical 
forests have the potential to alter microclimates, allowing atypical 
forest species to invade, increasing the chance of recurrent fires 
(Sherman et al. 2008, p. 536).
Conservation Efforts To Reduce Other Natural or Manmade Factors 
Affecting the Continued Existence of the Species
    As discussed under Factor A above, the Service, USFS, and PRDNER 
signed a CCA in 2014, to implement strategic conservation actions. In 
the context of Factor E, these actions include the development and 
implementation of programmatic reforestation and habitat enhancement 
efforts within areas degraded by hurricanes to improve the recovery of 
the elfin-woods warbler within EYNF and MCF (Service 2014, pp. 18-19). 
Additionally, the CCA will help develop and design studies to gather 
information on the elfin-woods warbler (e.g., habitat needs, habitat 
use, movement and activity patterns, responses to biotic and abiotic 
factors, and genetic variation) in order to better design and implement 
conservation strategies for the recovery of the species.
Summary of Factor E
    Based on the information available and limited distribution of the 
elfin-woods warbler, we believe that this species is currently 
threatened by natural or manmade factors such as

[[Page 40544]]

hurricanes and human-induced fire. The effects of climate change may 
exacerbate these threats by increasing intensity and frequency of 
hurricanes and environmental effects, although information is lacking 
on the specific extent of these effects. Thus, we consider these other 
natural and manmade factors to be threats to this species.

Determination

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to elfin-woods warbler. Current available information indicates that 
the elfin-woods warbler has a limited distribution, with only two known 
populations occurring within EYNF and MCF, including the private lands 
adjacent to MCF, and at least one possibly extirpated population from 
CCF. As discussed in the Summary of Factors Affecting the Species 
section of this rule, threats to the elfin-woods warbler include loss, 
fragmentation, and degradation of habitat on private lands adjacent to 
MCF (Factor A). Some of these lands are subjected to habitat 
modification caused by unsustainable agricultural practices (i.e., sun-
grown coffee plantations), small residential development, and livestock 
related activities. Moreover, the increase of urban development on 
private lands adjacent to EYNF and CCF has also negatively affected 
suitable elfin-woods warbler habitat around these forests. The 
activities result in the elimination of native forest, thus reducing 
the suitable habitat available and the habitat value for the elfin-
woods warbler.
    Other natural or manmade factors (i.e., hurricanes, the effects of 
climate change, human-induced fires; Factor E) also have been 
identified as threats to the species. There are only two known 
remaining populations making the species more vulnerable to extinction 
if one population is lost due to a catastrophic weather event. The 
effects of climate change also are expected to alter the structure and 
distribution of the habitat used by the elfin-woods warbler, which may 
be particularly susceptible because of the limited distribution and 
specific forest types used by the species. Human-induced fires have 
been reported in the Maricao area mostly within the lower southern 
slopes of the MCF and adjacent private lands, particularly during the 
dry season, and occasionally in the CCF area. Habitat disturbance 
caused by human-induced fires may also affect the ability of the 
species to disperse to other forested habitats.
    The Act defines an endangered species as any species that is ``in 
danger of extinction throughout all or a significant portion of its 
range'' and a threatened species as any species ``that is likely to 
become endangered throughout all or a significant portion of its range 
within the foreseeable future.'' We find that the elfin-woods warbler 
is not presently in danger of extinction throughout its entire range 
based on the low to moderate severity and non-immediacy of threats 
currently impacting the species. The available information indicates 
that elfin-woods warbler populations appear to be stable in MCF and 
that there are no immediate threats precipitating a demographic decline 
of the elfin-woods warbler in that forest. In Maricao, the species has 
been reported adjacent to the Commonwealth forest in shade-grown coffee 
plantations, demonstrating that the species may tolerate some degree of 
habitat disturbance. At EYNF, the most current information reported a 
declining trend of the elfin-woods warbler population, mainly 
attributed to hurricanes striking that forest. However, there are no 
specific studies corroborating that hurricanes are in fact the main 
cause of elfin-woods warbler population declines at EYNF and other 
factors may be influencing the decline (e.g., population low densities 
and patchy spatial arrangement). Although the species appears to be 
stable at the MCF, it may be declining at EYNF and extirpated from CCF. 
The cumulative effects of habitat modification by human actions (e.g., 
unsustainable agricultural practices) and natural events such as 
hurricanes would make the two known populations more vulnerable to 
extinction due to their restricted distribution, limited population 
numbers, and specific ecological requirements. Therefore, on the basis 
of the best available scientific and commercial information, we list 
the elfin-woods warbler as threatened in accordance with sections 3(20) 
and 4(a)(1) of the Act. We find that an endangered species status is 
not appropriate for elfin-woods warbler because the species is not 
currently in imminent danger of extinction throughout all of its range.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened under the Act include recognition, recovery actions, 
requirements for Federal protection, and prohibitions against certain 
practices. Recognition through listing results in public awareness, and 
conservation by Federal, State, Tribal, and local agencies; private 
organizations; and individuals. The Act encourages cooperation with the 
States and other countries and calls for recovery actions to be carried 
out for listed species. The protection required by Federal agencies and 
the prohibitions against certain activities are discussed, in part, 
below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Subsection 4(f) of the Act calls for the Service to develop 
and implement recovery plans for the conservation of endangered and 
threatened species. The recovery planning process involves the 
identification of actions that are necessary to halt or reverse the 
species' decline by addressing the threats to its survival and 
recovery. The goal of this process is to restore listed species to a 
point where they are secure, self-sustaining, and functioning 
components of their ecosystems.
    Recovery planning includes the development of a recovery outline 
shortly after a species is listed and preparation of a draft and final 
recovery plan. The recovery outline guides the immediate implementation 
of urgent recovery actions and describes the process to be used to 
develop a recovery plan. The plan may be revised to address continuing 
or new threats to the species, as new substantive information becomes 
available. The recovery plan identifies site-specific management 
actions that set a trigger for review of the five factors that control 
whether a species remains endangered or may be downlisted or delisted, 
and methods for monitoring recovery progress. Recovery plans also 
establish a framework for agencies to coordinate their recovery efforts 
and provide estimates of the cost of implementing recovery tasks. 
Recovery teams (composed of species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) are often 
established to develop recovery plans. When completed, the recovery 
outline, draft recovery plan, and the final recovery plan will be made 
available on our Web site (http://www.fws.gov/endangered), or from our 
Caribbean Ecological Services Field Office (see FOR FURTHER INFORMATION 
CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners.

[[Page 40545]]

Examples of recovery actions include habitat restoration (e.g., 
restoration of native vegetation), research, captive propagation and 
reintroduction, and outreach and education. The recovery of many listed 
species cannot be accomplished solely on Federal lands because their 
range may occur primarily or solely on non-Federal lands. To achieve 
recovery of these species requires cooperative conservation efforts on 
private, State, and Tribal lands.
    Following publication of this final listing rule, funding for 
recovery actions will be available from a variety of sources, including 
Federal budgets, State programs, and cost share grants for non-Federal 
landowners, the academic community, and nongovernmental organizations. 
In addition, pursuant to section 6 of the Act, the Commonwealth of 
Puerto Rico would be eligible for Federal funds to implement management 
actions that promote the protection or recovery of the elfin-woods 
warbler. Information on our grant programs that are available to aid 
species recovery can be found at: http://www.fws.gov/grants.
    Please let us know if you are interested in participating in 
recovery efforts for this species. Additionally, we invite you to 
submit any new information on this species whenever it becomes 
available and any information you may have for recovery planning 
purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7(a) of the Act requires Federal agencies to evaluate their 
actions with respect to any species that is proposed or listed as an 
endangered or threatened species and with respect to its critical 
habitat, if any is designated. Regulations implementing this 
interagency cooperation provision of the Act are codified at 50 CFR 
part 402. Section 7 (a)(1) of the Act directs all Federal agencies to 
``utilize their authorities in furtherance of the purposes of the Act 
by carrying out programs for the conservation of'' endangered and 
threatened species. Section 7(a)(2) of the Act requires Federal 
agencies to ensure that activities they authorize, fund, or carry out 
are not likely to jeopardize the continued existence of any endangered 
or threatened species or destroy or adversely modify its critical 
habitat. If a Federal action may affect a listed species or its 
critical habitat, the responsible Federal agency must enter into 
consultation with the Service.
    Federal agency actions within the species' habitat that may require 
consultation as described in the preceding paragraph include management 
and any other landscape-altering activities on Federal lands 
administered by the USFS; issuance of section 404 Clean Water Act (33 
U.S.C. 1251 et seq.) permits by the U.S. Army Corps of Engineers; and 
construction and maintenance of roads or highways by the Federal 
Highway Administration.

4(d) Rule

    Under section 4(d) of the Act, the Service has discretion to issue 
regulations that we find necessary and advisable to provide for the 
conservation of threatened wildlife. We may also prohibit by 
regulation, with respect to threatened wildlife, any action prohibited 
by section 9(a)(1) of the Act for endangered wildlife. 50 CFR 17.31(a) 
applies all the general prohibitions for endangered wildlife set forth 
at 50 CFR 17.21 to threatened wildlife; 50 CFR 17.31(c) states that 
whenever a 4(d) rule applies to a threatened species, the provisions of 
Sec.  17.31(a) do not apply to that species. Permit provisions for 
threatened species are set forth at 50 CFR 17.32.
    Some activities that would normally be prohibited under 50 CFR 
17.31 and 17.32 will contribute to the conservation of the elfin-woods 
warbler because habitats within some of the physically degraded private 
lands adjacent to elfin-woods warbler existing populations must be 
improved before they are suitable for the species. Therefore, for the 
elfin-woods warbler, the Service has determined that species-specific 
exceptions authorized under section 4(d) of the Act are necessary and 
advisable to promote the conservation of this species.
    As discussed above in the Summary of Factors Affecting the Species 
section of this listing rule, threats to the species include loss, 
fragmentation, and degradation of habitat due to unsustainable 
agricultural practices and land use requiring vegetation clearance. 
Agricultural practices occurring on private lands adjacent to MCF, 
especially those involving habitat modification (e.g., deforestation 
and conversion of shade-grown coffee to sun-grown coffee plantations), 
can result in vegetation removal and habitat alteration, thereby 
degrading habitats used by the elfin-woods warbler for feeding, 
sheltering, and reproduction.
    The private lands surrounding MCF are considered the most active 
coffee production lands in Puerto Rico. Sun-grown coffee plantations 
adjacent to MCF were converted several decades ago, resulting in the 
elimination of native forest overstory, reducing the habitat value for 
wildlife, including the elfin-woods warbler. Although the majority of 
the coffee-related agricultural lands were converted to sun-grown 
coffee plantations, several parcels of land surrounding MCF are 
currently part of a multi-agency habitat restoration initiative in 
southwestern Puerto Rico implemented by the Service and NRCS since 
2010, through the PFW, CP, and U.S. Department of Agriculture Farm Bill 
Programs. Activities that improve or restore physical habitat quality, 
such as the conversion of sun-grown coffee to shade-grown coffee, 
reforestation with native trees, riparian buffering, and forested 
habitat enhancement (i.e., exotic species removal, and native tree 
planting), would have a positive effect on elfin-woods warbler 
populations and would provide an overall conservation benefit to the 
species. The NRCS conservation practices promoted under this initiative 
are the Multi-Story Cropping (Practice 379) and Tree/Shrub 
Establishment (Practice 612) (USFWS 2011). The Multi-Story Cropping 
practice promotes the establishment of stands of trees or shrubs that 
are managed as overstory with an understory of woody and/or non-woody 
plants that are grown for a variety of products. The purpose of this 
practice is to improve crop diversity by growing mixed but compatible 
crops having different heights in the same area. This will improve soil 
quality, reduce erosion, enhance degraded areas, and provide habitat 
for wildlife species such as the elfin-woods warbler. The Tree/Shrub 
Establishment Practice promotes the establishment of woody plants by 
planting seedlings or cuttings, direct seeding, or natural 
regeneration. The purpose is to promote forest products such as timber, 
wildlife habitat, long-term erosion control, and improvement of water 
quality, and to improve or restore natural diversity.

Provisions of the 4(d) Rule

    Under this 4(d) rule, all of the prohibitions set forth at 50 CFR 
17.31 and 17.32 apply to the elfin-woods warbler, except that 
incidental take caused by the following activities conducted within 
habitats currently occupied by the elfin-woods warbler on private, 
Commonwealth, and Federal lands would not be prohibited, provided those 
activities both abide by the conservation measures in the rule and are 
conducted in accordance with applicable Commonwealth, Federal, and 
local laws and regulations:
    (1) The conversion of sun-grown coffee to shade-grown coffee 
plantations by the restoration and maintenance (i.e., removal of 
invasive, exotic, and feral species; shade and coffee tree seasonal 
pruning; shade and coffee tree planting and replacement; coffee bean 
harvest by

[[Page 40546]]

hands-on methods; and the use of standard pest control methods and 
fertilizers within the plantations) of shade-grown coffee plantations 
and native forests associated with this type of crop. To minimize 
disturbance to the elfin-woods warbler, shade and coffee tree seasonal 
pruning must be conducted between September 1 and February 28, which is 
outside the peak of the elfin-woods warbler's breeding season. The 
Service considers the use of pest control methods (e.g., pesticides, 
herbicides) and fertilizers ``standard'' when it is used only twice a 
year during the establishment period of shade and coffee trees (i.e., 
the first 2 years). During this period, the structure of the 
agroforestry system is not mature enough to sustain the occurrence of 
elfin-woods warblers within these areas.
    Once the shade-grown coffee system reaches its full functionality 
and structure (i.e., 3 to 4 years), few or no chemical fertilizers, 
herbicides, or pesticides are required, and their use would be 
restricted under the 4(d) rule. This is the time period when the shade-
grown coffee system is mature enough to support the presence of 
wildlife species. Researchers have found that the number of species of 
birds in coffee plantations with structurally and floristically diverse 
canopies is similar to the number of species in natural forest habitat 
and is higher than other agricultural landscapes without trees 
(Perfecto et al. 1996, pp. 603-605).
    The restoration of agricultural lands due to the planting of native 
trees to provide shade to coffee trees or by selective removal of 
exotic species creates physically stable and suitable habitats for the 
elfin-woods warbler. Moreover, the cultivation of shade-grown coffee 
has many other ecological and human-health benefits such as the 
reduction of soil erosion, moderation of soil temperatures, and reduced 
need for fertilizers and pesticides (Borkhataria et al. 2012, p.168). 
Therefore, restoration, conservation, and protection of shade-grown 
coffee plantations would provide suitable habitat for the feeding, 
sheltering, and reproduction activities of this species and may provide 
habitat to promote the elfin-woods warblers' dispersal and 
recolonization of lands adjacent to the existing populations.
    (2) Riparian buffer establishment through the planting of native 
vegetation and removal of exotic species may improve the habitat 
conditions of Gallery forests along the sub-watersheds associated with 
lands adjacent to the elfin-woods warbler's existing populations. 
Gallery forests serve as biological corridors that maintain 
connectivity between forested lands and associated agricultural lands, 
reducing the fragmentation in the landscape.
    (3) Reforestation and forested habitat enhancement projects within 
secondary forests (i.e., young and mature) that promote the 
establishment or improvement of habitat conditions for the species by 
the planting of native trees, selective removal of native and exotic 
trees, seasonal pruning of native and exotic trees, or a combination of 
these.
    The intent of these exceptions is to provide incentive for 
landowners to carry out these activities in a manner which we believe 
will provide benefits to the species such as: (1) Maintaining 
connectivity of suitable elfin-woods warbler habitats, allowing for 
dispersal between forested and agricultural lands; (2) minimizing 
habitat disturbance by conducting certain activities outside the peak 
of the elfin-woods warbler's breeding season (i.e., pruning between 
September 1 to February 28); (3) maximizing the amount of habitat that 
is available for the species; and (4) improving habitat quality. While 
these activities may cause some temporary disturbance to the elfin-
woods warbler or its habitat, we do not expect these activities to 
adversely affect the species' conservation efforts. In fact, we expect 
they will have a net beneficial effect on the species.
    Based on the rationale above, the provisions included in this rule 
authorized under section 4(d) of the Act are necessary and advisable to 
provide for the conservation of the elfin-woods warbler. Nothing in 
this 4(d) rule would change in any way the recovery planning provisions 
of section 4(f) of the Act, the consultation requirements under section 
7 of the Act, or the ability of the Service to enter into partnerships 
for the management and protection of the elfin-woods warbler.
    We may issue permits to carry out otherwise prohibited activities 
involving threatened wildlife under certain circumstances. Under 
regulations governing permits for threatened wildlife species, which 
are codified at 50 CFR 17.32, a permit may be issued for the following 
purposes: For scientific purposes, to enhance the propagation or 
survival of the species, economic hardship, zoological exhibition, 
educational purposes, and for incidental take in connection with 
otherwise lawful activities. There are also certain statutory 
exemptions from the prohibitions, which are found in sections 9 and 10 
of the Act.
    It is our policy, as published in the Federal Register on July 1, 
1994 (59 FR 34272), to identify to the maximum extent practicable at 
the time a species is listed, those activities that would or would not 
constitute a violation of section 9 of the Act (for this species, those 
section 9 prohibitions that would be adopted through the 4(d) rule). 
The intent of this policy is to increase public awareness of the effect 
of a final listing on proposed and ongoing activities within the range 
of a listed species. Based on the best available information, the 
following actions are unlikely to result in a violation of section 9, 
if these activities are carried out in accordance with existing 
regulations and permit requirements. This list is not comprehensive:
    (1) Activities authorized, funded, or carried out by Federal or 
Commonwealth agencies (e.g., expansion or construction of communication 
facilities; expansion of recreational facilities; pipeline 
construction; bridge construction; road rehabilitation and maintenance; 
expansion, construction, or maintenance of aqueduct facilities; habitat 
management; Federal and Commonwealth trust species reintroductions; 
trail maintenance; camping areas maintenance; research, repair, and 
restoration of landslides; etc.), when such activities are conducted in 
accordance with the consultation and planning requirements for listed 
species under section 7 of the Act; and
    (2) Agricultural and silviculture practices implemented within 
existing agricultural lands (i.e., degraded habitat not suitable for 
the species) other than sun- to shade-grown coffee conversion and 
maintenance, including herbicide, pesticide, and fertilizer use outside 
of coffee plantations, which are carried out in accordance with any 
Commonwealth and Federal existing regulations, permit and label 
requirements, and best management practices.
    We believe the following activities may potentially result in a 
violation of section 9 the Act. This list is not comprehensive:
    (1) Unauthorized collecting or handling of the species;
    (2) Destruction/alteration/fragmentation of habitat essential to 
fulfilling the lifecycle of the species; and
    (3) Introduction of nonnative species that compete with or prey 
upon the elfin-woods warbler.
    Questions regarding whether specific activities would constitute a 
violation of section 9 of the Act should be directed to the Caribbean 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).

[[Page 40547]]

Critical Habitat

    Section 3(5)(A) of the Act defines critical habitat as (i) the 
specific areas within the geographical area occupied by the species, at 
the time it is listed on which are found those physical or biological 
features (I) essential to the conservation of the species and (II) 
which may require special management considerations or protection; and 
(ii) specific areas outside the geographical area occupied by the 
species at the time it is listed upon a determination by the Secretary 
that such areas are essential for the conservation of the species. 
Elsewhere in this issue of the Federal Register we have published a 
proposed rule to designate critical habitat for the elfin-woods 
warbler.

Required Determinations

National Environmental Policy Act (42 U.S.C. 4321 et seq.)

    We have determined that environmental assessments and environmental 
impact statements, as defined under the authority of the National 
Environmental Policy Act, need not be prepared in connection with 
listing a species as an endangered or threatened species under the 
Endangered Species Act. We published a notice outlining our reasons for 
this determination in the Federal Register on October 25, 1983 (48 FR 
49244).

References Cited

    A complete list of references cited in this rulemaking is available 
on the Internet at http://www.regulations.gov and upon request from the 
Caribbean Ecological Services Field Office (see FOR FURTHER INFORMATION 
CONTACT).

Authors

    The primary authors of this final rule are the staff members of the 
Caribbean Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Reporting and 
recordkeeping requirements, Transportation.

Regulation Promulgation

    Accordingly, we amend part 17, subchapter B of chapter I, title 50 
of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority: 16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, unless 
otherwise noted.


0
2. Amend Sec.  17.11(h) by adding an entry for ``Warbler, elfin-woods'' 
to the List of Endangered and Threatened Wildlife in alphabetical order 
under BIRDS to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                       Species                                                   Vertebrate
------------------------------------------------------                        population where                                  Critical       Special
                                                          Historic range       endangered or         Status      When listed     habitat        rules
           Common name              Scientific name                              threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
                        Birds
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
Warbler, elfin-woods............  Setophaga angelae..  U.S.A. (PR)........  Entire.............  T                      866            NA      17.41(e)
 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

* * * * *

0
3. Amend Sec.  17.41 by adding paragraph (e) to read as follows:


Sec.  17.41  Special rules--birds.

* * * * *
    (e) Elfin-woods warbler (Setophaga angelae). (1) Prohibitions. 
Except as noted in paragraph (e)(2) of this section, all prohibitions 
and provisions of 50 CFR 17.31 and 17.32 apply to the elfin-woods 
warbler.
    (2) Exemptions from prohibitions. Incidental take of the elfin-
woods warbler will not be considered a violation of section 9 of the 
Act if the take results from any of the following when conducted within 
habitats currently occupied by the elfin-woods warbler provided these 
activities abide by the conservation measures set forth in this 
paragraph (e) and are conducted in accordance with applicable State, 
Federal, and local laws and regulations:
    (i) The conversion of sun-grown coffee to shade-grown coffee 
plantations by the restoration and maintenance (i.e., removal of 
invasive, exotic, and feral species; shade and coffee tree seasonal 
pruning; shade and coffee tree planting and replacement; coffee bean 
harvest by hands-on methods; and the use of standard pest control 
methods and fertilizers within the plantations) of shade-grown coffee 
plantations and native forests associated with this type of crop. To 
minimize disturbance to the elfin-woods warbler, shade and coffee tree 
seasonal pruning must be conducted between September 1 and February 28, 
which is the time period outside the peak of the elfin-woods warbler's 
breeding season. The Service considers the use of pest control methods 
(e.g., pesticides, herbicides) and fertilizers ``standard'' when it is 
used only twice a year during the establishment period of shade and 
coffee trees (i.e., the first 2 years). Once the shade-grown coffee 
system reaches its functionality and structure (i.e., 3 to 4 years), 
little or no chemical fertilizers, herbicides, or pesticides may be 
used.
    (ii) Riparian buffer establishment though the planting of native 
vegetation and selective removal of exotic species.
    (iii) Reforestation and forested habitat enhancement projects 
within secondary forests (i.e., young and mature) that promote the 
establishment or improvement of habitat conditions for the species by 
the planting of native trees, selective removal of native and exotic 
trees, seasonal pruning of native and exotic trees, or a combination of 
these.

    Dated: June 6, 2016.
Stephen Guertin,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2016-14540 Filed 6-21-16; 8:45 am]
 BILLING CODE 4333-15-P