Ecological strategies of a small hibernator, the western jumping mouse Zapus princeps

Abstract

The seasonal emergence, reproduction, diet, fat deposition, and immergence of six wild populations of Zapus princeps from elevations of 1860–2900 m were studied by trap–recapture methods and laboratory observations from April 1974 to November 1978. Emergence timing varied widely between and within sites in different years. It was not related to increasing elevation but to site quality. Vegetative growth was an excellent predictor of emergence timing at all sites. Emergence of males and females was synchronous except above 2200 m where males preceded females by 3–9 days. Field and laboratory experiments and observations were made on Z. princeps, including habitat preferences, competitive relationships, population density (maximum = 32.4/ha), length and timing of the active cycle (87 days), reproductive activity (1 litter/year), litter size [Formula: see text], age structure of populations, growth rates, seasonal fat deposition (0.65 g/day),and home-range size(0.17–0.61 ha). This attempts to formulate a coherent picture of the system of strategies by which a small hibernator adapts to its environment.