Population Dynamics of Beach Mice (Peromyscus polionotus ammobates) in Southern Alabama

Abstract

Population dynamics of Alabama beach mice (Peromyscus polionotus ammobates) were studied at two sites (Perdue and Ft. Morgan) on Bon Secour National Wildlife Refuge, Baldwin Co., Alabama, from January 1987 to November 1989; 997 mice were marked and released. Closed population models (program CAPTURE) and minimum number of mice known alive were used to obtain population indices; open population models (program JOLLY) were used to estimate survival probabilities. Population numbers fluctuated seasonally, with mice most abundant in winter and spring. Sex ratios neither varied seasonally nor differed from 1:1, although numerically more males than females were captured in 19 of 24 trapping periods. Percentage of subadults was highest in winter and lowest in summer, whereas percentage of reproductively active females was highest in autumn and winter and lowest in summer. Mean body mass of adult mice did not vary seasonally; females weighed more than males during the winter.