Estimates of dispersal and home-range fidelity in American black bears

Abstract

I examined dispersal, home-range establishment, and home-range fidelity in American black bears (Ursus americanus) using radiotelemetry data for individuals whose natal ranges were known (n 43), individuals whose natal ranges were identified using microsatellite DNA (n 13), and individuals whose natal ranges were unknown (n 86). Dispersal was highly male-biased. Nearly all males emigrated 2262 km from their natal ranges between the ages of 1 and 3 years. Some males continued to float, moving their ranges 1568 km between successive years. Most males settled into a permanent home range by age 4 years, and all males settled by age 7 years. One 8-year-old male apparently did not disperse and resided only 7 km from his natal range. Females were more philopatric and settled 07 km from their natal ranges. Only 1 female moved her range >20 km at the age of 5 years. The adaptive significance of male-biased natal dispersal is discussed. © 2010 American Society of Mammalogists.