Brownian Bridge Movement Models to Characterize Birds' Home Ranges

Abstract

Abstract. A Brownian bridge movement model (BBMM) is a relatively new concept that estimates the path of an animal's movement probabilistically from data recorded at brief intervals. A BBMM assumes that locations are not independent, whereas the “classical” kernel-density estimator (KDE) assumes they are. We estimated BBMM home ranges for 11 Black Vultures (Coragyps atratus) and 7 Turkey Vultures (Cathartes aura) equipped with satellite transmitters near Marine Corps Air Station Beaufort, South Carolina, from October 2006 to November 2008. The 95% BBMM home ranges (95% BBMM) of the two Black Vultures that traveled >100 km from the capture site were 833 and 2111 km2; of the nine that did not travel as far, 95% BBMM ranged from 33 to 778 km2 and averaged (± SE) 243 ± 76 km2. The majority of Turkey Vultures (n = 6) traveled >100 km from the capture site with 95% BBMM ranging from 923 to 7058 km2 and averaging 3173 ± 1109 km2. We also estimated KDE home ranges, using newer satellite technology for comparison ...