Landfill use by bald eagles in the chesapeake bay region

Abstract

We examined patterns in the use of landfills (rubbish dumps) in the Chesapeake Bay by Bald Eagles (Haliaeetus leucocephalus). Sites of solid waste landfills (n = 72) were located using state databases. Satellite tracking data from 64 eagles were used to track eagle movements hourly during daylight and once at midnight to determine roosting locations (2007-2012). Landfill use varied significantly with age class, with hatch-year birds using landfills six times more often than adults and twice as often as third- and fourth-year birds. Hatch-year birds spent significantly more time at landfills than expected based on landfill area relative to the study area outside of landfills. The relationship between time of year and eagle presence at landfills was not significant, though the results suggest a peak in landfill use in the late fall. There was spatial variation in landfill use, with 10% of the landfills used by study birds receiving 75% of the total landfill use. Landfills within two km of communal roosts received significantly more eagle activity than landfills farther from communal roosting sites. If eagle presence at landfills is indicative of foraging at these sites, the results provide evidence that foraging strategies in Bald Eagles change with age. Landfills may serve as important scavenging sites for hatch-year and second-year eagles, whereas older birds may be more successful obtaining higher quality prey elsewhere.