A preliminary investigation of the muskrat population of Gray's Lake, Idaho.

Authors(s): R. M. Williams

Publication:

Publisher:

Publication Date: 0000-00-00

Type: MS

Location: Moscow Idaho

Abstract: Muskrat populations and spring trapping harvest at Grays Lake were studied during the late 1940s. In spring and fall seasons in 1948, 35 trappers removed an estimated 10,000 muskrats. In spring 1950 5,325 muskrats were harvested; only a fraction of the total lake area was trapped. Counts of muskrat houses in 1949 indicate a breeding population of 8,140 and a winter population of 35,200 muskrats. Losses during winter were believed to be relatively light. Reproduction period (births) extended from late May to mid-August, with peaks in late June-early July. Litter sizes averaged nearly 7 (range 2-11). Average total production per female was 10.4 young, of which 84% survived to December. Marking of individual muskrats indicated summer and fall movements were confined to small areas; 75% of recaptures were within 50 yards of the original tagging site. Maximum distance moved was 200 yards. In spring, males averaged 909 g and females 837 g in weight. Average growth of juveniles was 47 g/month. Sex ratios remained fairly constant from litter through adults, indicating no differential sex mortality. No serious diseases or ectoparasites were evident during this study. During the 10-day spring (April) muskrat trapping season, trappers caught 1 goose, 27 ducks, and 173 coots.

Keywords: Gray's Lake, Idaho, breeding, animal, mammal, muskrat, Ondatra zibethicus, Mustelidae, management, hunting, human activity, population, mortality, habitat, radio collar, disease, parasite, bird, ornithology, Aves, goose, water bird, waterfowl, Anatidae, coot