Golden eagles are back from Canada, spending the winter in the eastern U.S.
Researcher Trish Miller said there are probably around 5,000 east of the Mississippi River, compared to estimates of 1,000 to 2,500 when she and her husband, Michael Lanzone, began studying them in 2005. Other scientists have come up with similar figures.
Golden eagles are among North America's largest birds of prey, some with wingspans broader than 7 feet (2.1 meters). They're mostly brown, but are named for the golden feathers at the back of the head and neck. An estimated 100,000 to 200,000 live worldwide, including Europe, Asia and North Africa. In North America they're far more numerous in the West, where an estimated 40,000 live or winter, but some can be found for at least part of the year in most of Canada and the United States, and parts of Mexico.
Miller, of Conservation Science Global in West Cape May, New Jersey, said the greatest numbers wintering in the eastern U.S. are probably along the Virginia-West Virginia state line, though she and Lanzone, of Cellular Tracking Technologies in Rio Grande, New Jersey, haven't analyzed likely densities.
Hundreds of camera traps, with bait set in front of motion-sensitive game cameras, have documented them in every state east of the Mississippi River and cellular tracking tags have shown them venturing into others, she said.
"A couple of the birds we've tagged in Alabama have gone to Mississippi and Louisiana. We have one bird we caught in Georgia that is right now in Missouri, in the Ozarks," she said Tuesday. "He's been spending several weeks there now. I don't know if he'll end up spending more time there or go down to Georgia."
Tennessee and Alabama are the focus of a habitat study she and Lanzone hope to complete by the end of 2020, she said.
Unlike bald eagles, golden eagles prefer remote forests and mountains. Miller said she and Lanzone rarely see the birds unless they're in a blind at a repeatedly visited camera trap. The scientists set up a box-shaped net launcher near the bait to catch birds for tagging while they wait in the blind where they hid before dawn.
Four tagged birds have returned to Alabama, and a fifth is on its way, Mercedes Bartkovich, in charge of Alabama's golden eagle research, said Tuesday.
There are certainly more golden eagles, but their elusiveness makes it hard to estimate how many winter in Alabama, said Bartkovich, a nongame wildlife biologist for the Alabama Department of Conservation and Natural Resources.
The first to return to Alabama this year was a female dubbed Coosa, at the Talladega National Forest. Keeton is at the Oakmulgee Wildlife Management Area and Trace at the Freedom Hills WMA. A female dubbed Natchez was in Illinois at the start of the week and a male named Coon Dog had just made his way from Tennessee into Alabama, Bartkovich said.
Alabama's tagging so far has been in the north, but this January's tagging trip will focus on the southern part of the state, Miller said.
The birds always return to the areas where they were tagged, Bartkovich said, and each follows a nearly identical migration route each year, sometimes with one path to and another from its breeding ground in Canada.
Coon Dog has flown farthest, often to the tips of Quebec and Newfoundland, Bartkovich said. Natchez and Trace went up around the eastern side of Hudson Bay and Keeton on the bay's western side.
Coosa "kind of went all over," Bartkovich said. "I can tell you where he went but not positively exactly where his breeding location was."
She said Coosa's most northern flight took him just east of a town called Labrador City, near the Labrador-Quebec line and about 480 miles (770 kilometers) east of James Bay, which projects southeast from Hudson Bay.
Coosa, Trace and Keeton all were tagged last January, Natchez and Coon Dog were both tagged at Freedom Hills, Natchez in 2015 and Coon Dog in 2016.
The birds don't have to be sedated - putting a hood over a bird's head calms it down, she said.
Golden eagles look a bit like juvenile bald eagles, but golden eagles' legs are feathered to their toes, unlike bald eagles' yellow legs. Golden eagles eat mammals such as rabbits, hares, ground squirrels and prairie dogs - and they do their own hunting, while bald eagles often steal fish from smaller raptors such as osprey.
OutdoorAlabama.com has maps showing some golden eagles paths but is no longer getting data for most of those birds.
"Sometimes we got multiple years of data from some of the birds, sometimes we just got a season," Bartkovich said. "It's sort of out of our hands once we get the transmitter on."