TRACKING WILDLIFE BY SATELLITE 



35 



Arctic National 



Wildlife Refuge 



Fig. 30. Movement patterns of muskoxen on 

 the Arctic National Wildlife Refuge 

 (ANWR), Alaska, 1986-1987. Data cour- 

 tesy of P. Reynolds. 



Brown Bear: Western Brooks Range 



Brown bears in the western Brooks Range have been 

 studied by H. Reynolds of ADFG since 1977 (Reynolds 

 and Hechtel 1980). This long-term study has made it pos- 

 sible to observe interactions among bears with known 

 family histories. Despite the wealth of information on this 

 bear population, frequent relocations during a single sea- 

 son have never been obtained, mostly due to logistic and 

 budgetary constraints. In July 1987, objectives of equip- 

 ping three adult females with radio collars included deter- 

 mining the minimum number of relocations needed to 

 adequately describe home ranges and assessing the degree 

 of spatial and temporal overlap among females, two of 

 which were a mother and her adult daughter. All three 

 were fitted with PTT's transmitting for 3 h twice daily. The 

 PTT's were programmed to suspend operation when the 

 bears were in dens. 



The increased number of seasonal locations for each of 

 the three bears during 1 987 made some new analyses pos- 

 sible. Overlap among home ranges of the three bears are 

 shown using modified minimum area polygons (Harvey 

 and Barbour 1965; Fig. 31). Only one location from any 

 group occurring within the 3-h duty cycle was used for 

 home range estimation. The magnitude of overlap among 

 the three must be interpreted while considering the limita- 

 tions of the home range estimation method. Overlap 

 among home ranges estimated here is likely overestimated 

 because location error is not considered; however, most 



home range estimation techniques are known to be sample 

 size-dependent (Anderson 1982; Swihart and Slade 

 1985b). The use of satellite telemetry enabled Reynolds to 

 obtain more than 100 locations for each bear during this 

 3-month period which is substantially more than would 

 have otherwise been possible. 



Brown Bear: Kodiak Island 



Kodiak Island's brown bear population has been the 

 focus of numerous studies. Investigations on the southern 

 part of the island have (1) revealed factors that influence 

 habitat use by brown bears, (2) assessed the efficiency of 

 aerial and ground inventories along salmon spawning- 

 streams, and (3) determined reasons for the use of particu- 

 lar streams (Barnes 1985). 



Two radio collars were deployed during summer 1987 

 in an attempt to refine previous information on the timing 

 of movements between salmon streams. Both PTT's were 

 programmed to transmit 8 h/day during summer and fall, 

 once every 4 days during denning, then to resume trans- 

 mitting 8 h/day in spring. Previous studies (Barnes 1985) 

 had shown that individual bears often moved from stream 

 to stream to feed on different runs of spawning salmon. 

 However, the timing of these movements was unknown 

 because inclement weather frequently made it unsafe to 

 locate bears with aircraft. Collars were not intended to 

 assist in habitat-use studies because of concern about the 

 precision of locations on Kodiak Island, where the terrain 



