NCASI comments on Bicknell’s thrush
The U.S. Fish
and Wildlife Service (Service) recently announced a 90-day finding on a
petition from the Center for Biological Diversity (CBD) requesting that the
Bicknell’s thrush (
Catharus bicknelli)
be listed as threatened or endangered under the Endangered Species Act and that
critical habitat be designated (77
Federal
Register 48934–48947). The Service has decided that the petition presents
substantial scientific or commercial information indicating that listing the
Bicknell’s thrush may be warranted. Thus, the Service has initiated a status
review for the thrush and is requesting scientific and commercial data and
other information regarding the status of and threats facing the species
throughout all of its range.
The Bicknell’s
thrush breeds in portions of the northeastern United States and southern
Canada, and winters in the Greater Antilles. On the breeding range, it largely
occurs in forests dominated by red spruce (Picea
rubens) and balsam fir (Abies
balsamea) and containing other tree species such as white birch (Betula papyrifera var. cordifolia). Total population size is
estimated to be approximately 95,000 to 126,000 individuals (77 FR 48936).
The CBD petition
alleges that the primary factor affecting the Bicknell’s thrush is the
potential influence of climate change on habitat availability. The petitioners
also assert that acid and nitrogen deposition, ground-level ozone, recreational
and wind energy development, precommercial thinning, predation, and many other
factors are affecting the species.
NCASI has
submitted technical comments on the 90-day finding to the Service. Best
available information indicates that the Bicknell’s thrush population in the
United States is stable or increasing. Concerns about potential future effects
of climate change are speculative and do not constitute evidence of a
substantial threat to the viability of Bicknell’s thrush in the foreseeable
future. Although studies have documented reduced density of Bicknell’s thrush
in precommercially thinned stands for 1-3 years following thinning, Bicknell’s
thrush continue to occur and nest in thinned stands; abundance increases within
4 years post-thinning; and use of precommercial thinning appears to be
unrelated to range-wide estimates of population trends for Bicknell’s thrush. In
conducting its status review, the Service should focus on factors shown to have
effects on population viability, and they should keep in mind that many animal
species are naturally uncommon. Thus, a small population size alone is an
inadequate basis for assessing extinction risk or listing under the Endangered
Species Act.
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