Showing papers by "William J. McShea published in 1993"

Variable Acorn Crops: Responses of White-Tailed Deer and other Mast Consumers

Abstract: We examined movements and behavior of female white-tailed deer ( Odocoileus virginianus ) relative to the acorn mast-fall from 1986 through 1989 in a mature deciduous forest in Front Royal, Virginia. Ten white-tailed deer with radiotransmitters increased their home range to incorporate acorn-producing areas during mast-fall. Consumption of acorns by deer constituted ca. 50% of foraging time during peak mast-fall; average consumption rate was 0.75 acorns/min searching. Although the number of acorns eaten by deer was correlated with mast-fall, a prolonged time was spent searching for acorns after mast-fall. Deer consumed 70% of marked acorns placed out during mast-fall, while medium-sized animals (e.g., Tamias striatus, Sciurus niger, Sciurus carolinensis ) consumed 61% of acorns placed out later in autumn. We hypothesize that high densities of deer may limit populations of more mast-dependent species, particularly at low acorn-crop densities.

Function of the star in the star-nosed mole, Condylura cristata

Abstract: The star-nosed mole, Condylura cristata , possesses curious behavioral and structural specializations of its proboscis. Nine positions and movements of the rays associated with various contexts are described. Bites were concentrated on strong electrical spots (clitellum and reproductive pores) when pursuing submerged worms, such as Lumbricus terrestris . On their first trials, six of seven moles preferred the simulated electrical field of an earthworm rather than an identical arrangement without an electrical field. Star movements, mole behavior, and preliminary experiments are consistent with the hypothesis that the star-nosed mole uses an electrical sense to detect prey; conclusions must remain tentative until it is possible to obtain repeated responses from individual moles or from a larger sample of individuals.