For my dissertation research, I
assisted the Alaska Department of Fish and Game (ADFG) on their moose calf
mortality study. Over the past 10 years the moose population in McGrath, Alaska
has been below the level required to meet subsistence needs of locals. As a
result, ADFG undertook an investigation as to determine the fate of their moose
calves. Fish and Game radio-collared 50 adult and sub-adult cow moose and
monitored their movement and reproductive status from 2001-2003. All calves
born to the cows were captured, radio-collared and monitored for subsequent
survival throughout the summer months. We investigated all calf mortality-sites
on a daily basis and their ultimate cause of death was resolved from scat, hair
and carcass disposition. Simultaneously while at the moose calf mortality
sites, I investigated understory and overstory vegetation characteristics with
the intent of capturing predator preference in hunting habitats.
Bear hair on a twig at the water's edge.
Based on summer 2001-2002 moose
calf mortality results, ADFG determined that calf recruitment was limited by
bear predation during parturition season. Adding a predator dimension to the
study in 2002, twenty GPS-collars were deployed on black bears to monitor their
habitat use in reference to moose calving grounds as they exit dens in
April. Black bear females maintainted smaller home ranges throughout the year as compared to males. Additionally, mixed and coniferous forests were selected moreso than other habitats for den sites. Our findings also suggest that male black bears overlap moreso with other GPS-collared competing black bears and conspecific black bear during the peak period of predation on moose calfs. This finding may be a function of over-abundance of moose calves in the area, resulting in potential predator satiation.
GPS collaring a black bear.
There are four major areas of
investigation in my Ph.D. thesis:
patterns of predation by multiple predators on a single species of prey
bear movements and habitat use during moose parturition
bear den-site characteristics in southwestern interior Alaska
and synchrony of moose parturition in relation to predation risk
The Kuskokwim River, McGrath, AK.
Vegetation sampling at a brown bear site.
Mark Keech, Shelly Szepanski, and Rick Swisher with the R44 at a black bear collaring site.