Bald Eagles, Our Greatest Conservation Success Story (Salish Sea Wild) 

Great question, Curtis. Here's a link to a paper by John Elliott et al that tried to answer part of that by looking at how much of the eagles' daily energy needs were being met by eating landfill proteins. We talked to John about his study as we researched this episode. It's his work we cited when talking about the eagles possibly seeking warmth and protection from the elements instead of food. Their data show less foraging than expected (though it varied widely among the eagle population, with some depending much more on garbage than others, which could mean increased survival chances for those birds). More recent tracking studies have shown that some eagles migrate from landfill to landfill to landfill as they move north, potential evidence that landfills are a factor in survival. To better answer the question, John's work and similar studies will have to be repeated at other landfills. www.researchgate.net/publication/232668628_Foraging_ecology_of_Bald_Eagles_at_an_urban_landfill -- Bob, SeaDoc Society