Movements of Bald Eagles (Haliaeetus leucocephalus) after rehabilitation from lead poisoning

Bald Eagles (Haliaeetus leucocephalus) have been negatively affected by environmental toxicants for decades, including lead. Although Bald Eagles are a well-studied species, little is known about their survival and movement after rehabilitation from lead poisoning. In this study, we used global positioning system transmitters to track and monitor three adult male Bald Eagles that were rehabilitated from lead poisoning in New York. We generated kernel density estimates (KDEs) to assess space use during the typical breeding season for Bald Eagles in New York (1 Feb -30 Jun). For the two eagles that survived, we estimated 95% KDEs of 2119 and 46,598 km(2), and 50% KDEs of 258 and 7013 km(2). For the eagle that died 55-61 days after release, we generated two minimum convex polygons (874 and 311 km(2)) representing separate areas of concentrated use. The two surviving eagles had different movement strategies, with one following a non-breeding migratory strategy to Canada, whereas the other used a non-breeding localized pattern mostly in New York. Mean minimum daily movement distances for the surviving birds were similar between individuals in both the typical breeding and non-breeding periods. However, the migratory individual exhibited more daily movements > 50 km (8%) than the non-migratory individual (2%). Our results represent the first available baseline survival and movement data for eagles post-rehabilitation from lead poisoning. The necropsy of the deceased bird in this study indicated a recurrence of lead poisoning. We recommend the tracking of Bald Eagles for extended periods after lead poisoning rehabilitation to determine productivity and survival rates after sublethal lead poisoning events.