early serai sites, as noted by Lesica and Cooper 

 ( 1 999). Both species are virtually absent in sand 

 flats or broad inter-dune troughs. Meadow Vole 

 is restricted to the edges and small depressions of 

 the sandhills where more mesic habitat is available 

 or nearby. Masked Shrew, Dusky Shrew, Mon- 

 tane Vole, and Deer Mouse are widespread, 

 although the latter species apparently is uncommon 

 in expansive sandflats and broad inter-dune 

 troughs. 



Five bird species noted in the sandhills are state 

 PIF Priority II species. For one of these. Ferrugi- 

 nous Hawk, there is no evidence of current 

 breeding, but the species was observed hunting in 

 the area and an old ground nest was found in the 

 West Hills. Presence of this hawk in the sandhills 

 is probably determined by prey availability and 

 landscape structure (nest sites), although habitat 

 availability could affect its presence indirectly 

 through influences on its favored prey (Bechard 

 and Schmutz 1 995 ), which in the Centennial Valley 

 are voles, ground squirrels, and pocket gophers 

 (Restani 1991). Our observations on the other 4 

 PIF Priority species (Long-billed Curlew, Sage 

 Thrasher, Brewer's Sparrow, Grasshopper 

 Sparrow) indicate confirmed or likely breeding in 

 the sandhiUs. Long-billed Curlews seek breeding 

 sites with short dense grass usually < 25 cm in 

 height (Allen 1 980, Pampush and Anthony 1993, 

 Paige and Ritter 1999). This species is currently 

 uncommon in the sandhills, but behavior of one 

 pair indicated the presence of young. Sage 

 Thrasher and Brewer's Sparrow are sagebrush 

 obligates, closely associated with sagebiiish of 

 different structure and negatively associated with 

 grass cover (Paige and Ritter 1 999, Reynolds et 

 al. 1999,Rotenberryetal. 1999). Populations of 

 these species drop where sagebrush cover is 

 below 1 0% over large areas. Sage Thrasher is 

 most closely associated with tall dense sage, while 

 Brewer's Sparrow occurs in sage < 1 .5 m tall and 

 in less dense stands. Brewer's Sparrow is wide- 

 spread and relatively abundant in the Centennial 

 Sandhills wherever sagebrush is present; Sage 

 Thrasher is restricted to small patches of taller big 



sage and dense stands of the same. Grasshopper 

 Sparrow occurs in the Centennial Sandhills in a 

 small and possibly isolated breeding population (at 

 least 3 singing males) in relatively dense grass with 

 low sagebrush cover, so far known only fi-om the 

 West Hills. Grasshopper Sparrow settles in sites 

 with taller grasses and generally avoids grasslands 

 with extensive shrub cover, although some shrub 

 cover is favored ( Vickery 1 996); in sagebrush- 

 grassland in southcentral Montana, this species 

 was significantly less abundant on plots that 

 experienced fire eradicating all sagebrush cover 

 (Bock and Bock 1987). 



We found no sign of Greater Sage-Grouse 

 {Centrocerciis urophasianus) in the sandhills 

 during our survey. Absence could be due in part 

 to a lack of adequate density and height of sage- 

 brush favored as summer habitat (J. Roscoe 

 personal communication). 



Only three amphibian and reptile species were 

 observed in the sandhills. None appear closely 

 associated with any habitat other than the various 

 adjacent wetlands. However, the population of 

 tiger salamander that exists in the upper Centennial 

 Valley may persist largely because of the close 

 proximity of the sandhills to extensive wetlands, 

 providing it ideal habitat in which to find refuge in 

 burrows during non-breeding periods. 



Our survey of diumal butterflies was so brief that 

 we could not identify pattems of landscape use. 

 Nevertheless, we can predict areas where some 

 species are likely to occur, based on their larval 

 food plant preferences (Opler 1 999). Larvae of 

 the 3 skipper species feed on grasses and sedges, 

 so we would expect them to occur widely in the 

 Sandhills. Riding's Saytr feeds on grasses, espe- 

 cially blue grama [Bouteloua gracilis), and will 

 probably be most prevalent in the East Hills where 

 it was commonly seen in 1999. Both Boisduval's 

 Blue and Sooty Hairstreak specialize on lupines 

 {Lupinus spp.), so we expect these butterfly 

 species to occur throughout the sandhills in all 

 successional stages, but more commonly in 



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