Gunn and Fournier. 2000.
Calf Survival and Seasonal Migrations of a Mainland Muskox Population.
113
pp.
ABSTRACT
Muskoxen
(Ovibos moschatus) disperse away from a winter concentration along
a broad valley drained by the Rae and Richardson rivers, west of Kugluktuk.
Before calving in late March – early April, the muskoxen migrate
up to 140 km north toward the coast.
In early August to October, the muskoxen slowly return to the
Rae-Richardson river valley. We documented those seasonal migrations using radio-collars
on 10-20 adult cows between 1988 and 1991.
We also used the radio- collars to locate herds to record seasonal
calf survival. The proportion
of calves among all muskoxen counted in May (13 +
0.9 SD) and November (11 +
0.42 SD) for all years combined was similar.
A decline in calf survival was only
significant
during summer 1989. We
suggest that the low proportion of calves may be partially a consequence
of low pregnancy rates as well as low survival.
Five of the 8 radio-collared cows that died were either confirmed
or probably grizzly bear kills. During
the study we found that the muskoxen were infected with a lungworm, which
may have contributed to deaths. This
report includes a trial to treat the lungworm.
Our documentation of seasonal movements contributes to effective
survey design and our results on calf and adult survival suggest that the
population is not likely to continue the increase described in the early
1970s and early 1980s.
|
