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Figure 1. Elk density on the expanded and Yoast Mine areas during winter aerial surveys <br />from 1994 through 2006. <br />20 <br />15 <br />d <br />:~ <br />s, <br />p 10 <br />a <br />W <br />s <br />0 <br />1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 <br />Year <br />Expanded survey area: 84.5 miZ (1994-1995), 89.5 mil (1996-2006). <br />Yoast survey area: 21.4 miZ (19942006). <br />detect animals and resulted in under counting. Considerably more elk were observed one month <br />later, January 1995, when the area was surveyed from a helicopter. The high elk densities <br />observed in 1996 (16.5 elk/mi2) and 2003 (13.0 elk/mi2) were likely influenced by excessive <br />snowpack during those yeazs in the higher elevations of the Williams Fork Mountains. The deep <br />snow likely pushed the ungulates out of the higher elevations and north into the survey azea <br />where reduced snow depths made walking easier and forage more accessible. The elevated <br />densities observed in January 1998 (14.2 elk/miz) and Febntaty 2005 (10.8 elk/miZ) could not be <br />explained by unusually deep snow, as snowfall was minimal in winter 1997-1998 and below <br />average in 2004-2005. Conversely, the elk may have taken advantage of the lower snowfall to <br />feed in grassland and sagebrush-grassland habitats where forage is usually inaccessible in winter <br />due to snow cover. The reduced numbers of elk observed in 2006 (5.8 elk/miz) may be <br /> <br />C <br />• <br />2006 Yoast Mine Wildlife Monitoring Page 5 <br />