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Biological Assessment for DMG Permit Renewals McClane Canyon & Munger Canyon Mines Potential impacts of the proposed actions to bald eagles are primarily disturbance of possible night-roosting areas around permitted surface disturbances (Moynahan 2006). However, given the bald eagle's low fidelity to night roosts, such impacts are not likely to cause measurable effects on bald eagles. Water depletion in the upper Colorado River basin resulting from McClane operations could potentially affect bald eagle winter foraging habitat. The effects of water depletion would depend on the extent that foraging conditions are altered or forage fish habitat is affected by the withdrawals. Because the volume of water withdrawal that will result from the McClane permit renewal represents a relatively small depletion to the upper Colorado River and does not represent a change in environmental baseline conditions, and because fish do not form the sole prey base for bald eagles in the Grand Valley, the water withdrawals occurring as a result of the renewal of the McClane permit are not likely to cause measurable effects on bald eagles. Mexican spotted owl (T). This bird was listed as threatened in 1993 at Federal Register 58(40):14248-14290 due to logging threats in its habitat. Due to low numbers, exacting habitat requirements, and low nesting productivity, populations in Colorado are vulnerable to extirpation (Kingery 1998). Its primary habitat in the region is mixed conifer forests dominated by Douglas- fir, ponderosa pine or other tall conifers (Andrews and Righter 1992). Less commonly, it inhabits steep, narrow canyons with cliffs and a perennial water source (Andrews and Righter 1992; Willey 1993). Canyon habitats typically contain conifer or riparian forests or at least clumps of tall trees (Willey 1993), but in Colorado, slickrock canyon habitat may only be sparsely vegetated with pinyon pine and juniper (Righter et al. 2004). Critical habitat for Mexican spotted owl was designated on August 31, 2004 at Federal Register 69(168):53183-53230. None of the three critical habitat units designated in Colorado encompass the assessment areas (USFWS 2006b). The total estimated population of Mexican spotted owls in the U.S. is between 777 and 1,554 birds (Gutierrez et al. 1995). Studies of two Mexican owl populations in Arizona and New Mexico showed a 1 percent and 4 percent decline over a 4-year period, but these results were not statistically significant (Gutierrez et al. 1994). The population status and trend of the Mexican spotted owl in Colorado is uncertain, but the bird is certainly rare. The highest count of Mexican spotted owls in Colorado was tallied in 1993-20 owls with 7 breeding pairs (Kingery 1998). Ongoing research conducted since 1989 by the U.S. Forest Service and BLM has confirmed the presence of two breeding populations in the state: one at Mesa Verde National Park and in the vicinity of Pike's Peak and the Wet Mountains (Kingery 1998). The approximately 30 historic records of Mexican spotted owls around the state may imply a formerly larger breeding distribution, or may represent vagrants wandering at the northern limits of the species' range (Kingery 1998). No historic or recent published records exist for Garfield County (Andrews and Righter 1992; Kingery 1998; CNHP 2005). The status of Mexican spotted owl in the assessment areas is unknown. Given the marginal suitability of habitat in the assessment areas and the paucity of documented occurrences of this species in west-central Colorado either historically or during recent survey efforts, it is unlikely that the Mexican spotted owl occupies the assessment areas. The impacts of the proposed actions on Mexican spotted owl would therefore be discountable or insignificant. Ferruginous hawk (S, SC). According to survey work by Colorado Breeding Bird Atlas (BBA) project, the ferruginous hawk is primarily a grassland species occurring in greatest abundance on the eastern plains of Colorado: 64 percent of BBA records were in grasslands, 26 percent were in woodlands, and 16 percent were in shrublands (Kingery 1998). Of the estimated 150 breeding pairs in the state (Andrews and Righter 1992), there are probably fewer than 10 pairs in western Colorado (Righter et al. 2004), known from shrub-steppe habitat in Moffat County and from semi-desert shrublands in the Grand Valley, particularly along the Book Cliffs (Kingery March 27. 2006 9 Rare Earth Science, LLC