LOUISVILLE - State Department of Environmental Conservation officials say a necropsy of an immature Bald Eagle found dead along the Grasse River in the town of Louisville indicates it had been attacked by another eagle.
A Massena-area couple were out for a hike when they found the dead eagle. They suspected the bird had been shot, a federal offense, but that did not turn out to be the case.
Blanche E. Town, principal fish and wildlife technician based in the DECs Potsdam office, said Environmental Conservation Officer John Ryan received a call regarding the discovery of the dead Bald Eagle along the Grasse River.
The cause of death was unknown. He relayed the eagle to me, and I sent it on to our pathology lab in Delmar. The lab determined that the eagle was killed by a conspecific or one of its own species, she said.
Ms. Town said, based on laboratory submissions, approximately 4 percent of eagle deaths are caused by another eagle, making it relatively uncommon. She said the dead eagle was determined to be a 2-year-old female.
Female bald eagles are larger than males. Eagles develop their size in the first year, but progress through various color phases of mostly brown with white mottling until attaining the dark brown body and distinct white head at the time of maturity, around the age of 5, she said.
Eagles are territorial by nature. The size of territory they establish and tolerance they exhibit for other eagles may be dependent upon the availability of forage and quality nesting sites. During the breeding season, they will defend their territories, but during the winter months it is common for them to forage and roost communally, according to Ms. Town.
Bald eagles may live over 30 years, but 15-25 years is their normal lifespan in the wild.
She said the bald eagle population is growing in St. Lawrence County.
It mirrors the growth we have experienced in the north country, the state and the northeastern United States. Breeding eagles are well dispersed throughout the county. They typically nest in mature forests near lakes, rivers or wetlands, Ms. Town said.
Sightings and photos are common in the early spring. The St. Lawrence River is the second largest wintering area in the state. Birds from northern Quebec and Ontario migrate here to winter, she said, noting that population also grows when eagles that winter on the Hudson and Delaware rivers move through the area as they head back home to Labrador and other Canadian provinces.