Breeding Bird Survey Results 2005

EXECUTIVE SUMMARY

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).

INTRODUCTION

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.

STUDY AREA

The 2,315-km˛ 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.

METHODS

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 ˝ 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.

RESULTS AND DISCUSSION (next page)


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