Maternal Denning Behavior and Survival of Juveniles in Opossums in Southeastern New York

Abstract

Maternal condition, denning behavior, and juvenile survival of 12 radiocollared Virginia opossums ( Didelphis virginiana ) were studied in southeastern New York, in the northern-most region of this species' distribution. Reproductive patterns of opossums observed in this study reflected the energetic demands of severe winter weather. Female opossums entered the breeding season in poor condition, but increased body weight by 11% while nursing their offspring. Litter size was correlated with a hind-leg fat index, a measure of the nutritional status of females. Locations of daytime dens of females indicated that all weaning dens were located in burrows and that den fidelity was greater during weaning than during nonweaning periods. Weaning dens were located in more densely vegetated habitats than nonweaning dens. Survival of juveniles prior to dispersal from the area in which weaning occurred was 22.3%, with most mortality following weaning. Increased den fidelity and use of burrows in dense cover for weaning dens are likely to increase juvenile survival.