Young eagles flock to the landfill drive-thru
Imagine for a moment that you're a young bald eagle soaring through the sky, scouring for a nice meal down below. You could hold out for fresh prey to skitter by. But your hunting skills aren't quite up to snuff, and hey, look! All your eagle friends are hanging out around a massive overflowing bowl of potential food in the middle of the landscape not too far off. So, of course, you're going to fly over for a quick bite.
And so it is that landfills—those large sources of easy food for wildlife—are supplementing the diets of our national symbol of freedom in the Chesapeake Bay region, according to a study by the Center for Conservation Biology, a research unit shared by Virginia Commonwealth University and the College of William and Mary. The results of the study that tracked the patterns of 64 eagles at 72 regional landfills were recently published in the Journal of Raptor Research.
Some of the data surprised researchers. "We thought eagles would use landfills more during the winter when there is less food available, but that didn't turn out to be the case," said Bryan Watts, Ph.D., director at the center and Mitchell A. Byrd Professor of Conservation Biology. What was not surprising, though: Young eagles really like going to the landfill drive-thru—a lot.
"We've done a lot of observations along the James River and what you'll see is that the young eagles are trying to steal prey from older eagles," Watts said. Basically, they are looking for a quick, easy meal while honing their hunting skills. Instead of swooping down on prey, they pirate, beg and scavenge. The landfills are a gold mine.
Hatch-year eagles are the biggest users. The data indicated they visit landfills six times more often than adults. Second-year birds used landfills four times more often than the grown-ups. As eagles get older and become more effective hunters, they move away from the landfills in favor of higher-quality food that's a bit harder to get talons around.
"Effectively, these landfills are supplementing a number of the scavenger species and they're maintaining larger populations than what the natural landscape could sustain without the landfills," Watts said.
This means the landfill scavenging isn't such a bad thing. Juvenile survivorship is essential to survivorship of the species—it wasn't that long ago that eagles were still on the endangered species watch list.
But in the same way we worry about the nutrition and safety of humans eating at fast food restaurants, eagles dining at landfills raises the obvious question: Is it safe for young birds to be snacking on human trash?
"There are risks for the food in these dumps. It's being dumped for a reason, and it's something that I think warrants investigation," said Watts, who pointed to recent eagle deaths in South Carolina from secondary poisoning from barbiturates. The eagles had eaten the carcasses of cats and dogs that had been euthanized at animal shelters.
This is not a one off—some shelters dump thousands of euthanized animals every year—and there is no way to know yet exactly what the birds are eating from the landfills.
"We're interested in, What are the birds doing? What are they feeding on? What are the implications of that relative to eagle management or landfill management?" Watts said.
Eagles are not the only birds feasting at the end of our food chain. Researchers are also interested in what is happening in the gull population around landfills. Like eagles, gulls flock to landfills en masse, and they're also roosting and leaving waste in the surrounding landscape. The concern is that gull droppings might disperse different microbes or chemicals around landfills, creating a contaminants halo. Perhaps a Mother Nature wake-up call?
"I think we as a society like our landfills out of sight," Watts said. "We just take our trash out to the corner and we don't think much more about it. Which is fine. But some of these other species we are sort of supporting—now and then certain things pop up that we should think more about."
The landfill research was part of a broader study kicked off in 2007 at Aberdeen Proving Ground. Eagles were getting caught and dying in military power lines, so researchers worked to determine which electrical lines should be buried to make the environment safer for eagles. It was a costly yet necessary solution to the problem of human practices unintentionally harming the environment.