Washington Ground Squirrel Surveys in Adams, Douglas, and Grant Counties, Washington, 2004 PDF Format - [1.66MB]

Washington Ground Squirrel Surveys in Adams, Douglas, and Grant Counties, Washington, 2004 Rich Finger, Gary J. Wiles, Jim Tabor, and Eric Cummins June 2007 Executive Summary Washington Ground Squirrel Photo by Jodie Delavan We surveyed a total of 303 Washington ground squirrel sites from late March to early June 2004 and confirmed occupancy at 218 of 247 (88%) sites that were classified as occupied during surveys conducted from 2001-2003. Occupancy rates for subregions of Washington ground squirrel sites typically exceeded 85%. However, the Seep Lakes Area in Grant County, the Hatton Area in Adams County, and the Foster Coulee Area in Douglas County each showed declines of =35% in occupancy rates from 2001-2003 to 2004. The reduction in the Seep Lakes Area exceeded the findings of Dr. Paul Sherman, who observed a 17% decline in active sites in this area from 1999 to 2001. The Black Rock Coulee and Sagebrush Flats Areas in Grant County experienced 15% and 11% declines in active sites from 2001-2003 to 2004, respectively. Nine previously undocumented sites were discovered in 2004. Most (67.5%, n = 156) active Washington ground squirrel sites in 2004 were characterized by small estimates of burrow numbers (i.e., 1-50 burrows), with 17.7% (n = 41) of sites containing an estimated 51-100 burrows, 14.3% of sites (n = 33) having >100 burrows, and 0.4% (n = 1) of sites having an undetermined number of burrows. Areas predominated by small sites were the Foster Coulee, Duffy Creek, Saddle Mountains, Beezley Hills, and Sagebrush Flats Areas, whereas the Warden, Moses Coulee, Lind, Soap Lake, and Seep Lakes Areas contained relatively more large sites. The Warden Area had by far the largest mean estimate of burrow numbers per site, followed by the Moses Coulee, Soap Lake, and Smyrna Bench Areas. Thirty-one (93.9%) of 33 large sites occurred in Grant County, with the greatest number (n = 10) present in the Moses Coulee Area. Eighty-six (37.2%) of the 231 active sites occurred on federal land, 69 (29.9%) were on private land, 37 (16.0%) were on Nature Conservancy land, 37 (16.0%) were on WDFW and other state land, and 2 (0.9%) were on local school district land. Biases in counting burrows and documenting sites means that some of our findings should be interpreted with caution. We identified eight areas (Seep Lakes, Hatton, Foster Coulee, Soap Lake, Warden, Ritzville, Lind, and Duffy Creek) where conservation concerns may be greatest for Washington ground squirrels. Recommendations for improved survey methodologies are provided for future work.