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Stoller-ESER-128
EXECUTIVE SUMMARY
Breeding bird surveys (BBSs) have been conducted annually
since 1985 (no surveys were conducted in 1992 and 1993) to
monitor bird populations on the Idaho National Laboratory (INL)
Site. In 2009, we conducted surveys from June 3 to 30 along
13 established routes, five of which are part of a
nationwide survey administered by the U.S. Geological Survey
(USGS), and eight of which circumscribe INL Site facilities.
We documented 5,072 birds from 55 species during these
surveys. Bird abundance was greater than the 1985-2008
average of 5,018 birds, but the number of species observed
(i.e., species richness) was lower than the 22-year average
of 59.
Compared with past surveys, we observed similar patterns of
bird abundance among those species that are typically most
numerous. In 2009, the five species that were surveyed in
greatest abundance were horned lark (Eremophila alpestris,
n = 1,466), western meadowlark (Sturnella neglecta, n
= 1,071), Brewer’s sparrow (Spizella breweri, n =
743), sage thrasher (Oreoscoptes montanus, n = 516),
and sage sparrow (Amphispiza belli, n = 367). During
23 years of breeding bird surveys on the INL Site, these
species have been the five most abundant 18 times, and in
the remaining five years they were among the six most
abundant species. Considering declines reported in
populations of sagebrush-obligate species throughout the
intermountain west, this trend indicates that the quality of
sagebrush-steppe habitat on the INL Site remains stable.
Although three new species were added in the past two years
to the list of birds that have been observed at least once
during BBSs on the INL Site, no new observations were made
in 2009. Four species were observed, however, that had been
recorded in ≤ 6 of the past 22 years. These include American
goldfinch (Carduelis tristis), western tanager (Piranga
ludoviciana), northern mockingbird (Mimus polyglottos),
and northern pintail (Anas acuta).
Species observed during the 2009 BBSs that are considered
imperiled or critically imperiled in Idaho include the
long-billed curlew (Numenius americanus, n = 2),
Franklin’s gull (Larus pipixcan, n = 26), and
grasshopper sparrow (Ammodramus savannarum, n = 4).
FUTURE DATA
ANALYSIS
With over two decades of BBS data collected, we are well
positioned to conduct a long-term analysis of bird
population trends for species occupying the INL Site. Past
reports have provided details regarding particular species,
but no effort has been made to consider a comprehensive
analysis of all BBS data from the INL Site. In the near
future, we plan to analyze all data from past BBSs, and to
investigate long-term trends in bird abundance and species
richness. The results of such an analysis will be submitted
to a peer-reviewed journal for publication and will be
included in an annual report to the U.S. Department of
Energy.
Landscape Change and Habitat Variation
The habitat and vegetation communities across the INL Site
are a mosaic of sagebrush-steppe habitat. The INL Site has
experienced some large, natural disturbances (e.g.,
wildfire) which have caused changes in vegetation community
composition and distribution across the site. Little is
known, however, concerning responses of bird populations to
alterations of habitat composition and distribution across
the landscape and how habitat fragmentation can influence
local populations. Local bird populations and community
assemblages can respond to these habitat changes, and the
long-term BBS data should reflect these changes. We will
investigate the patterns of habitat change in conjunction
with changes in observed bird abundance and richness along
routes.
Long-term Community Diversity Trend
Diversity indices have not been calculated each year, and a
useful comparison would be to calculate Shannon’s H and EH
for all BBS routes for all years to assess which routes have
experienced significant change in bird community abundance.
The initial community diversity results reported here
consider community differences between different routes in
the same year. It is unknown how diversity on the same route
has changed over time. A number of community similarity
indices, such as Morisita’s index, can be calculated to
address this question. We anticipate coupling the results
from the spatial analysis described above with the results
from community diversity change over time to present a
comprehensive description of how bird communities have
changed on the INL Site since 1985.
Full 2009 Breeding Bird
Survey Report (pdf format)
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