Population Dynamics of Agouti and Albino Meadow Voles in High-Quality, Grassland Habitats

Populations of agouti and albino meadow voles (Microtus pennsylvanicus) were censused weekly within eight 0.1-ha enclosures (four replicates per treatment) from 26 June to 4 December 1992. Results supported the hypothesis that there was no significant difference in the growth and structure of populations of albino meadow voles compared to populations of agouti meadow voles within habitats of high nutritional quality and heavy vegetative cover. No significant difference in mean-weekly densities of populations or rates of recruitment was found between coat-color treatments. Few significant differences in measures of population quality, such as the percentage of adults in breeding condition or differences in mean body mass of adults, occurred between treatments. During the removal period (6 December 1992 through 2 January 1993), 770 voles (478 albino and 292 agouti) were captured. A large percentage of albino (87%) and agouti (76%) voles removed during this period had not been captured previously suggesting that live-trapping may be a poor estimator of population density of meadow voles in habitats of high quality.