[Federal Register Volume 59, Number 170 (Friday, September 2, 1994)]
[Proposed Rules]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-21785]


[[Page Unknown]]

[Federal Register: September 2, 1994]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

 

Endangered and Threatened Wildlife and Plants; 1-Year Finding for 
a Petition To List the Pacific Coast Population of the Cactus Wren 
Under the Endangered Species Act

AGENCY: Fish and Wildlife Service, Interior.


ACTION: Notice of 1-year petition finding.

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SUMMARY: The Fish and Wildlife Service (Service), pursuant to the 
Endangered Species Act of 1973, as amended (Act), announces a 1-year 
finding on a petition to add the Pacific coast population of the cactus 
wren (Campylorhynchus brunneicapillus couesi) to the List of Endangered 
and Threatened Wildlife. After a review of all available scientific and 
commercial information, the Service determines that listing is not 
warranted at this time and hereby transfers the petitioned entity from 
category 2 to category 3B of the Candidate Notice of Review. The 
Service concludes that the cactus wrens occupying coastal southern 
California do not constitute a distinct population segment. Therefore, 
the Service concludes that the Pacific coast population of the cactus 
wren is not a listable entity.

DATES: The finding announced in this document was made on August 29, 
1994. Comments and information may be submitted until further notice.

ADDRESSES: Comments and materials regarding this petition finding may 
be submitted to the Field Supervisor, U.S. Fish and Wildlife Service, 
Carlsbad Field Office, 2730 Loker Avenue West, Carlsbad, California 
92008. The complete file for this notice, including the petitions, 
administrative finding, supporting data, and comments, is available for 
inspection, by appointment, during normal business hours at the above 
address.

FOR FURTHER INFORMATION CONTACT:
Mr. Gail C. Kobetich, Field Supervisor, at the address listed above 
(telephone 619/431-9440).

SUPPLEMENTARY INFORMATION:

Background

    Pursuant to section 4(b)(3)(B) of the Act, the Service is required 
to make a finding within 12 months of the date of the receipt of a 
petition to revise the Lists of Endangered and Threatened Wildlife and 
Plants on whether the petition is (a) not warranted, (b) warranted, or 
(c) warranted but precluded for immediate proposal by other proposals 
of higher priority. Section 4(b)(3)(C) requires that petitions for 
which the requested action is found to be ``warranted but precluded'' 
should be treated as though resubmitted on the date of such finding. 
Therefore, a subsequent finding should be made within 12 months.
    On September 21, 1990, the Service received petitions from the San 
Diego Biodiversity Project and Palomar Audubon Society to list the 
``San Diego cactus wren'', Campylorhynchus brunneicapillus 
sandiegensis, as an endangered species pursuant to section 4 of the 
Act. The San Diego cactus wren, as described, occurs from San Juan 
Creek in southern Orange County through western San Diego County 
southward to Valle de las Palmas in Baja California, which is just 
south of the U.S.-Mexico border.
    The American Ornithologists' Union Committee on Classification and 
Nomenclature (Committee) did not recognize the San Diego cactus wren 
(C. b. sandiegensis) as a subspecies of the cactus wren 
(Campylorhynchus brunneicapillus). The Committee has concluded that C. 
b. sandiegensis is intermediate between C. b. couesi, a widespread 
subspecies found in southwestern United States and northern, mainland 
Mexico, and C. b. bryanti, a suspecies recognized as occurring from San 
Diego County, California, to northern Baja California, Mexico (B. 
Monroe, in litt., 1990; R. Banks, in litt, 1994).
    The Service considers the Committee to be the recognized authority 
on the taxonomy of the birds of North America. Since the conclusion of 
the committee is that C. b. sandiegensis likely only represents an 
intermediate form between two recognized subspecies of cactus wren, it 
is not currently under consideration for addition to the Federal List 
of Endangered and Threatened Wildlife and Plants.
    On March 22, 1991, the Service announced its 90-day finding on the 
petitions (56 FR 12146), and indicated that we would treat the 
petitions to list C. b. sandiegensis as a petition to list the coastal 
population of C. b. couesi, because the cactus wrens residing in 
coastal California may be disjunct from other cactus wrens, and may 
constitute a distinct vertebrate population segment that could qualify 
for listing under the Act. Under section 3(15) of the Act the term 
``species'' includes any distinct population segment of any species of 
vertebrate fish and wildlife which interbreeds when mature. Thus, we 
indicated that the petition had presented substantial information 
indicating that the requested action may be warranted. Based upon our 
reevaluation of information received, the Service concludes that the 
coastal population of cactus wren consists of Pacific coastal portions 
of C. b couesi and C. b. bryanti.
    However, Congressional intent indicates that the Service is to list 
populations only ``sparingly''. In determining the appropriateness of 
listing a vertebrate population segment under the Act, the Service 
considers available scientific evidence regarding the population's 
discreetness or distinctiveness and regarding the population's 
significance to the species as a whole.
    The cactus wren is a resident species, and numbers of cactus wrens 
residing in coastal sage scrub of coastal southern California have 
declined as a result of the expressed effects of many of the same 
factors that have similarly impacted the largely sympatric, threatened 
coastal California gnatcatcher (Polioptila californica californica). 
All of the published literature on the status of coastal sage scrub 
vegetation types in California supports the conclusion that this plant 
community is one of the most depleted habitat types in the United 
States.
    However, it is currently evident that the cactus wrens residing in 
coastal sage scrub plant communities are not distinct from other cactus 
wrens. Therefore, cactus wrens occupying coastal southern California do 
not constitute a distinct vertebrate population segment. For instance, 
although the coastal birds almost always nest in cactus, cactus is a 
preferred nesting substrate of cactus wrens elsewhere in California and 
in the remainder of the species' range in the United States. Perhaps 
more importantly, no apparent morphological or other morphometric 
differences have been detected to date that distinguish coastal birds 
from other cactus wrens.
    In addition, it is apparent that the habitat preference of coastal 
birds (coastal sage scrub) does not readily separate them from other 
members of the subspecies. Several treatments exist describing various 
types of scrub communities in southern California and Baja California. 
The coastal sage scrub plant formation grades into coastal succulent 
scrub and eventually into Sonoran desert scrub. Although some gaps in 
the range of the species may exist, birds representing C. b. bryanti or 
C. b. couesi, as currently defined by the American Ornithologist's 
Union (R. Banks, in litt., 1994), likely occupy all of these ``scrub'' 
plant communities or formations. Hence, because cactus wrens evidently 
occupy several plant communities and are not isolated in habitat, the 
Service concludes that providing protection pursuant to the Act for 
birds living in some (but not all) of these plant communities and 
habitats is inappropriate.
    Furthermore, the cactus wrens occupying coastal southern California 
are not likely significant to the continued existence of a species that 
occurs in portions of southern California, southern Nevada, Arizona, 
New Mexico, Utah, and Texas, in the United States, and mainland Mexico. 
The species is relatively common throughout much of its range. However, 
since the birds occupying coastal southern California are not distinct, 
the issue of significance need not be addressed.
    This finding announced herein is not intended to discount the 
importance of the coastal sage scrub ecosystem in southern California, 
which is the subject of intense multispecies and ecosystem planning 
efforts that have been undertaken and endorsed by the Service; the 
Secretary of Interior; the Resources Agency, State of California; the 
California Department of Fish and Game; numerous local governments; 
citizens' groups; and individual citizens. Cactus wrens living in 
coastal southern California have declined in numbers, and coastal sage 
scrub habitats are becoming increasingly depleted. Efforts to conserve 
these depleted habitats will be of benefit to cactus wrens residing in 
coastal southern California, Federal candidate species, and other 
sensitive species.
    In the absence of sufficient evidence that a listable entity 
exists, the Service concludes that it is appropriate to transfer the 
``coastal population of the cactus wren'' from category 2 candidate 
status to category 3B. Category 3B species are taxa that, on the basis 
of current taxonomic understanding, do not represent distinct taxa, 
including vertebrate populations, meeting the Act's definition of 
``species.'' Such taxa could be reevaluated in the future on the basis 
of new information. In that regard, the service will continue to accept 
information on the taxonomy and distinctness of cactus wren taxa and 
the significance of the Pacific coast population segment.

Authority

    The authority for this action is the Endangered Species Act of 
1973, as amended (16 U.S.C. 1531 et seq.).

List of Subjects in 50 CFR Part 17

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

    Dated: August 29, 1994.
Mollie H. Beattie,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 94-21785 Filed 9-1-94; 8:45 am]
BILLING CODE 4310-55-M