Annual breeding bird surveys have been conducted
on the INL since 1985 to monitor changes in bird populations.
Surveys were conducted during 2005 from June 3 to June 27. A
total of 6,726 individuals representing 71 species of birds were
recorded along 14 permanent routes. Horned lark (N=2077),
western meadowlark (N=1087), Brewer’s sparrow (N=661), sage
thrasher (N=598), and sage sparrow (N=389) continue to be the
top five most abundant species on the INL. American white
pelican, rough-legged hawk, and canvasback were recorded this
year for the first time during these surveys. Species with a
state rank of rare or uncommon, imperiled, or critically
imperiled recorded in 2005 include American white pelican (N=6),
ferruginous hawk (N=15), long-billed curlew (N=9), Franklin’s
gull (N=123), ring-billed gull (N=2), western burrowing owl
(N=4), loggerhead shrike (N=40), northern mockingbird (N=1), and
lark bunting (N=4).
The Breeding Bird Survey (BBS) is a large-scale
survey of North American birds. It is a roadside route survey of
avifauna designed to monitor abundance and distribution of birds
primarily covering the continental United States and southern
Canada, although survey routes have recently been initiated in
Alaska and northern Mexico (Sauer et al. 2003). The BBS was
started in the eastern U.S. in 1966 with over 3,500 routes
currently surveyed each June by experienced birders (USGS 2001).
The primary objective of the BBS is the
estimation of population change for songbirds. However, the data
have many potential uses, and investigators have used the data
to address a variety of research and management objectives.
The Idaho National Laboratory (INL), located in
southeastern Idaho, is comprised of large expanses of relatively
undisturbed shrub-steppe and grassland habitat. This area was
designated as a National Environmental Research Park in 1975 and
serves as an outdoor laboratory to assess environmental impacts
of nuclear energy development technologies. Since 1985, official
BBS and unofficial facility routes have been surveyed at the INL.
These surveys yield useful information about population
dynamics, effects of weather and fire on avian abundance,
effects of INL facilities on avifauna, and the breeding status
of a number of bird species of concern, including sagebrush
obligate species and other species exhibiting declines
throughout their range (e.g., see Belthoff and Ellsworth 1996,
1999 and 2000, Belthoff et al. 1998, and Ellsworth 2001).
This report summarizes results of surveys
conducted in 2005 at the INL and compares findings to those from
previous years.
The 2,315-km² INL is located approximately 48 km
west of Idaho Falls on the upper Snake River Plain in
southeastern Idaho, and occupies portions of Bingham,
Bonneville, Butte, Clark, and Jefferson counties. The area is a
semi-arid, cold desert with an elevation of approximately
1500 m above sea level. Anderson et al. (1996) detailed the
climate, geology, and vegetation of the INL. Briefly, vegetation
in the study area is typical of shrub-steppe ecosystems and is
dominated by woody, mid-height shrubs and perennial
bunchgrasses. Big sagebrush (Artemisia tridentata)
dominates much of the vegetation on the site, but other primary
shrubs include green rabbitbrush (Chrysothamnus viscidiflorus),
shadscale (Atriplex confertifolia), and winterfat (Krascheninnikovia
lanata). Native grasses that are dominant throughout the
site are bottlebrush squirreltail (Elymus elymoides),
thickspike wheatgrass (Elymus lanceolatus),
needle-and-thread grass (Hesperostipa comata), Indian
ricegrass (Achnatherum hymenoides), and bluebunch
wheatgrass (Pseudoroegneria spicata). Basalt lava flows
dominate the geology of the region, and the topography is flat
to gently rolling, with the exception of East and Middle Buttes,
which protrude from the southern portion of the area. The
southern extensions of two of the largest mountain ranges in
Idaho (Lost River and Lemhi Mountains) rise above the INL site
and Snake River Plain to the north and west. The area
experiences hot, dry summers and cold winters (Short 1986).
Annual precipitation averages approximately 20 cm, and most of
this occurs during the spring. Surface water in the summer is
limited to residual flows of the Big Lost River and Birch Creek,
each of which are diverted upstream of the site for agriculture
and flood prevention. During the spring, the Big Lost River may
flow into an ephemeral wetland known as the Lost River Sinks,
which can provide nesting and migratory stopover habitat for
waterfowl and shorebirds. Several human-made wastewater
treatment ponds are located near research facilities which
attract birds that prefer aquatic habitats.
Fourteen Breeding Bird Survey routes were
surveyed June 3-27, 2005 (Figure 1). Five remote routes are
standard 40-km BBS routes, data from which are reported to the
USGS Biological Resources Division annually. These routes
traverse the remote areas of the INL and include major habitat
types throughout the site. Eight facility routes are located in
and around major INL facility complexes. An additional survey
route was established in 1997 around the CFA Wastewater
Treatment Facility (WTF) as part of an experiment designed to
monitor how wastewater application affects flora and fauna.
The North American Breeding Bird Survey protocol
(USGS 2001), provided by USGS Patuxent Wildlife Research Center,
was followed in completing each of these surveys. For remote
routes we located 50 stops at approximately 0.5-mile (0.8 km)
intervals and counted all individual birds (except dependent
young) of all species seen or heard during a 3-minute period
within 0.25-mile (0.4 km) of the stop. Facility routes consist
of 18–60 stop locations at approximately 0.2-mile (0.32 km)
intervals and individual birds were recorded if they were within
0.1-mile (0.16 km) from the observer (i.e., half the distance
between stops). Individuals known or strongly suspected to have
been counted at a previous stop were not counted. Surveys began
approximately ½ hour before official sunrise as given by the
Astronomical Applications Department, U.S. Naval Observatory
(2005). A certified Breeding Bird Survey observer relayed counts
verbally from outside the vehicle to an assistant who recorded
the information on an official data sheet. Each route took
approximately 1- 6 hours to complete.
Temperature, wind speed, and cloud cover were
recorded at the start and end of each survey route. Surveys were
conducted only under satisfactory weather conditions including
good visibility, little or no precipitation, and light winds in
order to be comparable to previous years. Survey dates for each
route can be found in Appendix A.
Trends for selected species were calculated by
using least squares. Trend data is used to display what
populations of selected species have been doing over time and
their responses to habitat change.
