138 



A sighting was made of a migrant bald eagle In fall of 198O. 



Harriers : Marsh hawks were common on the study area and undoubtedly 

 nested there. Although young birds were observed, no nests were 

 found, 



Falcons : Kestrels were the most commonly observed raptor. Numerous 

 nests were observed in snags, most often in ponderosa pine habitats. 



A prairie falcon aerie was located in a scoria cliff Just southeast 

 of the study area. Three young fledged from that aerie in 198I. 



Four sightings of peregrine falcons were made on the study area 

 during migration periods. 



Two sightings of merlins were obtained during the study period. 

 Merlins may have nested on the study area undetected. Three 

 pairs of merlins nested on the adjacent Sand Creek study area in 

 1980. 



Owls : Great horned owls were commonly seen on the study 

 area. Three nest sites were located (Table 65), two in sandstone 

 outcrops and a stick nest in a ponderosa pine tree. Three 

 families of burrowing owls were observed during the summer of 

 1981, two of which resided in prairie dog towns (Figure 70). 



A snowy owl was observed in the northern part of the study area 

 during the 198O-8I winter. A single long-eared owl and single 

 short-eared owl were seen on the Foster Creek study area in 1981. 



Nongame Mammals 



Twenty-one species of mammals, including game species, were 

 observed on the Foster Creek study area (Table 66). The black- 

 tailed prairie dog is listed by Flath (198I) as a species of 

 special concern in Montana. 



Twenty-three prairie dog towns are located with the boundary of 

 the study area (Table 67). Mean town size is 36. 1 acres 

 (1^.^ hectares) (Figure 72). Intensive foot surveys during July 

 of 1980 and 1981 failed to reveal evidence of black-footed 

 ferret activity on any of these sites, which are periodically 

 subject to prairie dog control measures. 



Results of small mammal sampling on the study area are summarized 

 in Table 68. Location of traplines is illustrated in Figure 68. 

 The largest number of captures was obtained in riparian habitat 

 but only two species were caught. Poor trapping success in all 

 habitats probably reflect depressed population densities of small 

 mammals due to drought conditions. 



Other species possibly occuring on the study area (excluding bats) 

 include: masked shrew iSoxzx. clm/LZui] , mountain cottontail 



