by Tamara Dietrich • Contact Reporter
October 12, 2015
Much like human teenagers, juvenile bald eagles know just where to scavenge for junk food. For teenagers, it's fast food joints. For young eagles, it's landfills.
And just as teenagers sometimes eat what isn't good for them, juvenile bald eagles dining at dumps can inadvertently ingest heavy metals, poisons, pharmaceuticals and even non-food items – substances that can sicken or even kill them.
Bird expert Bryan Watts at the College of William and Mary in Williamsburg has studied bald eagles in the Chesapeake Bay region for years, and now has published a paper on his study of their landfill eating habits in the Journal of Raptor Research. Watts is founder and director of the college's Center for Conservation Biology.
What his study found is that hatch-year birds feast on landfills six time more often than adults, and twice as often as third- or fourth-year birds. By the time they mature around age 5 and have developed into more efficient hunters, they shift to a healthier fresh-meat diet.
"They're going to landfills because it's an easy meal," Watts said. "They don't have the skills yet to effectively hunt consistently, so they go to where the cheap food is.
"The landfills we have in the area … are magnets for birds, particularly during the winter period. They get tens of thousands of birds – they're like a beehive."
It's long been suspected that young bald eagles frequent landfills, he said, and wildlife experts have anecdotal evidence supporting it.
Last month, for instance, when the Wildlife Center of Virginia in Waynesboro released a rehabilitated adult bald eagle at the York River State Park, they tracked its movements over several days.
"It basically went right to the King and Queen County landfill," said Dave McRuer, director of veterinary services at the wildlife center. "It spent three days there. Likely it was using that for food.."
Until Watts' study, however, it wasn't known for sure how bald eagles fit into the larger "beehive" landfill population – which largely consist of more well-known scavengers including ring-billed gulls, crows and black vultures – or whether the bald eagles that frequented these dumps were simply regular "landfill bums" or a more transient population.
Since 2007, Watts has outfitted about 75 bald eagles nestlings and adults with GPS tracking devices as part of his studies. Data they transmit has shown they rove as far as Canada and the Great Lakes before returning to the bay to settle down and breed.
It's that data that also shows the youngsters frequent more than 70 landfills throughout the Chesapeake Bay region from Virginia and Maryland to Pennsylvania and New Jersey.
While landfills can offer inexperienced raptors a quick and easy meal, it's not always a nutritious or even safe one.
At the wildlife center, McRuer said, sick bald eagles found in or near landfills are brought in that test positive for lead, for rodenticides used to kill rats and mice, and for pesticides commonly used in farming. Some birds are brought in coated with a strange oil that renders them unable to fly.
"It is legal in Virginia for vet clinics to dispose of dead animals in landfills," McRuer said. "And there are rules in place for landfills that, when these animals come in, they have to be immediately buried. Unfortunately, that doesn't always happen."
If the carcasses are available, eagles will scavenge them and could die as a result.
The Virginia Department of Game and Inland Fisheries is investigating an incident from last year in which two bald eagles ingested sodium pentobarbital in a landfill in western Virginia, Mc Ruer said.
And South Carolina, said Watts, has recently experienced an outbreak of secondary poisoning of bald eagles by barbiturates used to euthanize animals.
At Houston-based Waste Management Inc., which manages several landfills in Virginia, including the Bethel landfill in Hampton, spokeswoman Lisa Kardell said they do see adult eagles occasionally at the facility, but haven't seen any sick ones. The company contracts wildlife services with the U.S. Department of Agriculture to handle any issues involving sick animals, she said.
"We do cover all exposed waste at the end of each day," Kardell said, so there's no exposed waste for the birds or animals to scavenge on at the end of the day."
The wildlife center has eight bald eagles for rehabilitation at the moment, McRuer said, one of which was found both poisoned and with a large fish hook in its stomach.
But the facility is bracing for more bald eagles in a bout a month's time as deer season begins, he said. Every year, the birds scavenge dead deer and the gut piles left behind by hunters after field dressing their kills.
The lead bullets used by hunters shatter into tiny fragments, McRuer said. A piece smaller than a grain of rice is enough to kill a bald eagle.
About 80 percent of the eagles admitted to the center have "measurable levels" of lead in their blood, he said. Acute levels can kill a bird outright, while smaller levels damage them neurologically.
"It makes them uncoordinated," McRuer said. "Which means it can fly, but it's not going to be able to react in time to avoid the car or the truck on the road. … It's almost as if they're flying drunk."
Hunters can avoid inadvertently poisoning bald eagles by burying their gut piles, he said, or by switching to copper bullets.
Copper bullets cost a bit more and can add $7 to $8 per hunt, he said, but "it's a really minor cost compared to the environmental stewardship that you're providing and saving the lives of these scavangers."
The significance of his landfill study, said Watts, expands our knowledge of bald eagle ecology.
But it can also to raise awareness of landfills and the "open question" of what might be in them as well as the potential impact, he said – not just on eagles, but on other species as well.
The carcasses of euthanized animals should also be properly managed when they're land filled, he said,
"We have the choice, when those are dumped, that we bury them so they're not accessible to eagles," Watts said.
"These landfills not only are sources for young eagles to go and feed," he said. "They're also potentially a 'sink' where eagles are going in, but not all of them are coming out. So we certainly are proponents of better landfill management."
Dietrich can be reached by phone at 757-247-7892.
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