2007 Summaries of Wildlife Research Findings - Minnesota State ...

Table 1. Causes of mortality of radiocollared black bears ≥1 year old from the Chippewa National Forest (CNF), Camp Ripley,
Voyageurs National Park (VNP), and Northwestern (NW) Minnesota, 1981–2007. Bears did not necessarily die in the area where
they usually lived (e.g., hunting was not permitted within Camp Ripley or VNP, but bears were killed by hunters when they traveled
outside these areas).
CNF Camp Ripley VNP NW All combined
Shot by hunter 220 11 14 3 248
Likely shot by hunter a 8 1 0 0 9
Shot as nuisance 22 2 1 0 25
Vehicle collision 12 7 1 1 21
Other human-caused death 9 0 0 0 9
Natural mortality 7 3 4 0 14
Died from unknown causes 3 2 0 0 5
Total deaths 281 26 20 4 331
a
Lost track of during the hunting season.
Table 2. Reproductive rates (cubs/female), mean litter size, and proportion of females with cubs (in all cases, counting only litters
in which at least 1 cub survived 1 year) in winter dens (March) in VNP (1997–2008), CNF (1981–2008) and Camp Ripley (1991–
2008) (n = 4+ year-old female-years of observation). Reproduction increased from north (VNP) to south (Camp Ripley). Data
from the new study site in the northwest are as yet too sparse to add to the table.
Age of female
Repro
rate
VNP (n = 56) CNF (n = 403) Camp Ripley (n = 45)
Litter
size
Prop
w/ cubs
360
Repro
rate
Litter
size
Prop
w/ cubs
Repro
rate
Litter
size
Prop
w/ cubs
4–6 yrs 0.59 2.0 0.29 0.84 2.3 0.37 1.04 2.2 0.48
7–25 yrs 1.15 2.7 0.44 1.34 2.8 0.48 1.50 2.7 0.55
4–25 yrs 0.98 2.5 0.39 1.15 2.6 0.44 1.24 2.4 0.51