DISPERSAL OF JUVENILE FISHERS IN MAINE

We studied natal dispersal of fishers (Martes pennanti) in a harvested population in southcentral Maine during 1984-90 because of concern over the high level of harvest and a lack of information about fisher dispersal. Probability that an individual would disperse by the end of its first year was 73 and 100% for males and females, respectively (n = 21 M, 12 F). However, 32% of males and no females dispersed before the age of 9 months. Mean distance between natal and adult home ranges did not differ (t = 0.16, P = 0.88) between males (n = 8, xBAR = 10.8 km, range = 4.1-19.5) and females (n = 5, xBAR = 11.2 km, range = 5.0-18.9). Dispersal, in combination with intrasexual territoriality of adults, may limit fisher density and competition for food. Dispersal of nearly all juveniles allowed them to quickly replace adults removed by fur trapping. However, the short distances moved by dispersing fishers may limit their ability to recolonize areas from which fishers have been extirpated, and may reduce interchange among isolated populations.