Black bears raid eagle nests at military base.

In the US, black bears sometimes invade bald eagle nests and chase or eat chicks too small to fly, threatening populations of these birds of prey.

The black bear sleeps soundly in the eagle's nest. Photo: FWS — The black bear sleeps soundly in the eagle's nest. Photo: *FWS*

A black bear was caught sleeping in an unexpected spot: a bald eagle's nest. Researchers found the bear asleep while surveying the eagle's nest at a military base in Alaska. Black bears ( Ursus americanus ) occasionally take advantage of nests built by eagles. This intrusion threatens bald eagles and their chicks, according to the U.S. Fish and Wildlife Service (FWS), Live Science reported on July 26.

"In the past, only a few eagle nests have been raided by black bears with unfortunate consequences for the nest's owner," FWS shared on Facebook. Such incidents often result in the disappearance of the chicks.

Bears often eat eggs and chicks in nests, according to Steve B. Lewis, a wildlife biologist with the FWS who led a survey of nests at Joint Base Elmendorf-Richardson (JBER) in southern Alaska. "It's difficult to say exactly how many bears are invading eagle nests because we can't spend a lot of time monitoring what's happening or have cameras recording," Lewis said.

During a helicopter survey in May, researchers discovered a female bald eagle ( Haliaeetus leucocephalus ) incubating eggs in a nest that had been invaded by a sleepy bear. A week later, the eggs were left behind while both the female and her mate were busy nearby. Lewis and his colleagues were unsure whether the incubation attempt had failed or if the female had simply temporarily stopped incubating. Male eagles often take over the female's role in incubating eggs, especially in cold climates like Alaska. For that reason, Lewis suspected the nest had been damaged in the spring, long before the bear entered.

The bald eagle is the largest resident bird of prey in Alaska, with a wingspan of approximately 2.3 meters. This predator builds the largest nests in North America, with some nests measuring 2.4 meters wide and weighing over 1.8 tons. These enormous nests can provide a safe resting place for black bears. The bear might casually climb the tree and decide to take a nap.

The smell of fish emanating from the nest could also attract the bear. Eagle nests can be quite smelly because the fish that adult birds catch for their chicks are sometimes left uneaten. According to Lewis, that food is often not completely consumed, trampled in the nest, and rots. Bears have extremely sensitive noses, so perhaps the bear was attracted by the smelly nest.

Bald eagles were listed as endangered in the U.S. in 1978 after their numbers plummeted due to habitat destruction, illegal hunting, pesticides, and poison traps, according to the Alaska Department of Fish and Wildlife (ADFG). Thanks to conservation and monitoring efforts, they are recovering.

An Khang (According to Live Science )

Source link