. The Canadian field-naturalist. UJ O < 30 I- Z 20 UJ O 10 Juvenile + Juvenile o I III'. - lliJl Adult ^ 11 llou 3 5 SPRING DAYS lllll- â OF 3 5 7 9 AUTUMN TRAPPING Figure 5. The temporal distribution of adult and juvenile males and females during spring and autumn harvests (1978-1980).. Figure 6. The disproportionate sex ratio of harvested adult and juvenile Muskrats; the representation of females was greatest in the population subjected to the highest mortality. three impoundments were not significant (p > ). The mean placental scar count for all impoundments was In spring 19
. The Canadian field-naturalist. UJ O < 30 I- Z 20 UJ O 10 Juvenile + Juvenile o I III'. - lliJl Adult ^ 11 llou 3 5 SPRING DAYS lllll- â OF 3 5 7 9 AUTUMN TRAPPING Figure 5. The temporal distribution of adult and juvenile males and females during spring and autumn harvests (1978-1980).. Figure 6. The disproportionate sex ratio of harvested adult and juvenile Muskrats; the representation of females was greatest in the population subjected to the highest mortality. three impoundments were not significant (p > ). The mean placental scar count for all impoundments was In spring 1979, breeding was early, and nine adult females trapped during the public trapping season were pregnant with visible embryos. Eight of the pregnant females were from Impoundment S. The mean number of embryos/pregnant female was (s= ). The one pregnant female from Impound- ment SA carried nine embryos. The overall average was embryos/ pregnant female (s = ). Assuming the embryos was representative of all impound- ments over the three-year period, the average number of litters/season was Eight females (5 â autumn; 3 â spring) had given birth to (or were carrying) one litter, and all eight were aged by molar fluting as being 1 year old. Eight of the 19 females (42%) from Impoundment SA bearing scars were < 1 year old. Five percent of females < 1 year old and removed from Impound- ment SA were pregnant or had given birth to one litter. As many of those juvenile muskrats examined were autumn-caught and from second or third litters, the actual percentage of juveniles which had bred their first summer would have been considerably higher. No muskrats< 1 year old from Impoundments S or A were pregnant or had given birth. One female, ear-tagged as a 825 g juvenile on 29 August 1980, was pregnant when caught later during. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloratio
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