Snowshoe hares in Alaska, II. Home range and ecology during an early population increase

Abstract

A segment of a continuing study of Snowshoe Hares was conducted from May 1960 to November 1961, near College, Alaska. Objectives regarding home range, reproduction, behavior, age-determination criteria, and census methods were achieved by Iive-trapping and snaring. The Schnabel (Krumholz) formula and Petersen ratio for estimating population size were invalidated by differential trap response. The calendar graph, Webb strip-census, Hartman toe-clip ratio, pellet count, and road survey all proved poor or useless as used during this study for estimating hare abundance in this area. An increase in hare sign in marginal habitat between 1958 and 1961 indicated an increase in population density. Some hares were caught many times in succession in the same trap. Many more avoided traps, some for periods of nearly two years. Inclement weather restricted movements of hares. Adult and juvenile sex ratios were 1:1. The season of births extended from mid-May to early August. There was a mean of 4.6 fetuses per female per pregnancy. Hare parasites noted were: Mosgovoyia pectinata, Taenia pisiformis, Dirofilaria scapiceps, Obeliscoides cuniculi, Protostrongylus bouqhtoni, Haemaphysalis leporispalustris, and Hoplopsyllus glacialis. Exclusive-boundary-strip home range decreased significantly at the .01 level from 14.5 acreas at a low population density to 13.1 acreas at a higher density. A juvenile female hare made the maximum despersal movement noted, 1.6 miles. Snow collected on vegetation formed winter cover for hares. Hares used burrows occasionally. A sound resembling a low click ("tch") was observed in hares. Possible displacement behavior was observed in hares. Two litters were found in simple depressions in the leaves, and one in a nest-like form. Leverets less than 24 hours old could move from their place of birth. A hare's foot color cannot be used as an age criterion in Alaska in summer, since adults may have brown, white, or mottled hind feet. The epiphyseal groove appears to close at approximately seven months. Juvenile males can be recognized until December by a short, stubby penis, and juvenile females by a short, blunt vulva and lack of palpable teats. A combination of body weight and hind-foot length is recommended for determining the ages of juvenile hares. A lens weight of 160 mg. can be used to separate hares less than a year old from older hares.