Preferences of Red-Backed Voles and Deer Mice for Differing Structural Habitats
Some rodents specialize in their use of habitats while others occur in a variety of habitats. Although cover density is correlated with habitat use by some species, whether structure affects choice by rodents is unknown. The preferences of habitat specialists and generalists were determined by their time allocation among differing structural variables. Variables included horizontal and vertical density, height of horizontal, and vertical versus horizontal cover. Preference of a mouse was assessed by the percent of time spent with a structural type. The habitat specialists, Gapper's red-backed voles (Clethrionomys gapperi) preferred greater densities of both vertical and horizontal cover. Clethrionomys showed no preference for height of cover, nor for equal densities of horizontal versus vertical cover. Preferences for the greater density of horizontal cover were similar for the high height of horizontal cover at standard low-light intensity and at no light. Laboratory-reared Clethrionomys, without field experience, expressed stronger preferences than did the wild-reared Clethrionomys. The preferences of a habitat generalist, deer mice (Peromyscus maniculatus), were tested for height, and densities of horizontal and vertical cover. Wild Peromyscus did not prefer the different heights of horizontal cover nor the different densities of vertical cover. Wild Peromyscus preferred the greater density of horizontal cover. Laboratory-reared Peromyscus preferred the greater density of vertical and horizontal cover. Preferences of Peromyscus were neither as strong nor as consistent as the preferences of Clethrionomys. Vulnerabilities of red-backed voles and deer mice to domestic ferrets werw tested at two densities of vertical cover. Red-backed voles were more vulnerable with less vertical cover. Vulnerability of deer mice did not differ between the different vertical cover densities. Vertical and horizontal cover may reduce the vole's vulnerability to both mammalian and avian predators respectively. Reduced vulnerability is one explanation for Clethrionomys' inherent preferences for greater cover. Deer mice may use other strategies to evade predators which allow them to use a wider variety of habitats.
Wywialowski, Alice P. (1985). Preferences of red-backed voles and deer mice for differing structural habitats. PhD. 84p.