. The Canadian field-naturalist. 1984 Parker and Maxwell: Trapping Seasons for Muskrats 295 140 120 1-100 CO LU > ^ 80 < X 60 CD I- 20. 1978 1979 1980 Figure 2. Changes in the contributions to annual harvests by the three study impoundments subjected to differ- ent seasonal trapping pressures. Composition The proportions of juveniles { ), due mainly to the small samples (harvests) in spring 1979 (n = 20) and 1980 (n = 20). The autumn ratios of juve- niles in Impoundment SA, although consistently greater than those in Impoundment A, were not signif- icantly so. The lowest percentage o
. The Canadian field-naturalist. 1984 Parker and Maxwell: Trapping Seasons for Muskrats 295 140 120 1-100 CO LU > ^ 80 < X 60 CD I- 20. 1978 1979 1980 Figure 2. Changes in the contributions to annual harvests by the three study impoundments subjected to differ- ent seasonal trapping pressures. Composition The proportions of juveniles { ), due mainly to the small samples (harvests) in spring 1979 (n = 20) and 1980 (n = 20). The autumn ratios of juve- niles in Impoundment SA, although consistently greater than those in Impoundment A, were not signif- icantly so. The lowest percentage of juveniles in the spring harvests, and highest in the autumn harvests, were from Impoundment SA. Muskrats were more readily trapped in the autumn than in the spring (Figure 4). In autumn, 97% of the harvest was realized after eight days of trapping; in spring 88% of the final harvest had been removed in that time (2X2 contingency table; X" = ; df = 3; p ), respectively. The juvenile male:female ratios for spring and autumn harvests were and (p>), respectively. The proportion of males in the adult samples was significantly less than in the juvenile samples for spring (x- = ; df = 1; p < ) and autumn (x - = ; df = I; p I yr) which had previously given birth. The mean counts of placental scars, by impoundment, are shown in Table I. Differences in placental scar counts for the 100. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Naturalists' Club
Size: 1567px × 1595px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorottawafieldnaturalistsclub, bookcentury1900, bookcolle
