Species: Bombus (Bombus) occidentalis

G - 200,000-2,500,000 square km (about 80,000-1,000,000 square miles) - G - The current range is partially uncertain. In addition to a distinct cluster of populations in northern British Columbia and Alaska (Williams et al., 2012), this bee ranged along the west coast of North America from southern British Columbia to central California and east to northern Nevada, Arizona and New Mexico (Thorp 2005, Evans et al. 2008). Milliron (1971) indicated that the species ranged as far east as the Dakotas and Nebraska, and Schmidt and Jacobson (2005) found it in the Sky Islands of the southern Arizona mountains in the 1990s and early 2000s. Johnson (2009) also lists specimen records from three counties in southwestern South Dakota collected in the 1920s and 1930s, as well as one from far to the east in Brooking County in 1929. In Canada this bee was documented in British Columbia, Alberta, and Yukon. While this bee was said to be persisting mostly eastward by Thorp (2005), Cranshaw (2010) reports it has now declined in Colorado which is very near its eastern limit. Farther west, the Oregon Natural Heritage Program has records from several places in 2006-2008, mostly singletons (in one case one among 2000 bumblebee observations), but 49 were found in a prairie in northeastern Oregon during 2007-2008, for about 5% of bumblebees in June, and around 2% later in the season Rao <i>et al</i>. (2011). See Rao and Stephen (2007) for more information on the Polk County records. According to Sarina Jepsen of the Xerces Society (email to Nicole Capuano, September 2009) there were documented records for 2009 in Jefferson County, Washington; near Mount Hood in Oregon; and Kootenay Lake, British Columbia. Otherwise, records in at least southern British Columbia appear to cease after 2005 (COSEWIC, 2009, Rao and Stephen, 2007), but the species was still 2.2% in a 2007 bumblebee sample in Alberta (Evan et. al., 2009) compared to 8.4% in 1998. Syd Cannings (pers. comm. to Nicole Capuano, September 2009) reports this species is still fairly common and locally abundant in the Yukon Territories and Koch (2011) found the species to be still common in central Alaska. In the lower 48 The Xerces Society has 2012 records only for one place each in Oregon, Washington, and Wyoming, and from one place each in Colorado and Montana in 2011, and a different place in Montana in 2010.