Breeding Bird Survey Results 2006

EXECUTIVE SUMMARY

Annual breeding bird surveys have been conducted on the Idaho National Laboratory (INL) since 1985 to monitor changes in bird populations. Surveys were conducted in in 2006 during May and June. A total of 5,974 individuals representing 66 species of birds were recorded along 13 permanent routes. Horned lark (n=1616), western meadowlark (n=1055), Brewer’s sparrow (n=794), sage thrasher (n=458), sage sparrow (n=333) and mourning dove (n=333) are the top six most abundant species on the INL. Nine species indicated as Species of Greatest Conservation Need recorded include Brewer’s sparrow (n=794), sage grouse (n=46), Franklin’s gull (n=41), ferruginous hawk (n=10), western burrowing owl (n=5), long-billed curlew (n=5), short-eared owl (n=4), Wilson’s phalarope (n=4), and Merlin (n=1). This is only the second year that a Merlin was observed during the annual Breeding Bird Survey since the survey began in 1985.

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 2001a).

The primary objective of the BBS is the estimation of population change for songbirds. However, the data have many potential uses, and investigators have addressed 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, affects 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 2006 at the INL and compares findings to BBS surveys from previous years.

These annual surveys provide valuable long-term data for land managers and allow them to determine impacts of activities conducted at the INL and surrounding areas on breeding bird populations. These data also contribute to a nationwide database of bird population trends that is used by state and federal agencies.

STUDY AREA

The 894-mi˛ (2,315-km˛) INL is located approximately 30 mi (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 4921 ft (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 8 in. (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

Thirteen Breeding Bird Survey routes were surveyed once each from May 18 – June 16, 2006 (Figure 1). Five remote routes are standard 25-mi (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.

The North American Breeding Bird Survey protocol provided by USGS Patuxent Wildlife Research Center (USGS 2001b), was followed during these surveys. On 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 recounted. Surveys began approximately ˝ hour before official sunrise as given by the Astronomical Applications Department, U.S. Naval Observatory (2005). A certified BBS 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 are in Appendix B.

Single Factor Analysis of Variance was used to test the differences among years for all routes, and facility and remote routes for both abundance and species diversity. Even though comparisons between remote routes were conducted comparisons between facility routes, and facility and remote routes are problematic since the areas surveyed are not consistent. A level of 0.05 was used to determine significance. Appendix B contains summaries of the data and results from the analysis of variance. 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)


Related Topics:


Home | Background | Surveillance Land Management | Education | Research | Risk Assessment | Publications |  Links | Feedback | Opportunities