By Mary Kiesau, Conservancy bird nerd
Yes, we are into Latin or Scientific names around here, mostly because they are just so interesting, or maybe because it makes us look smart (or not so smart as the case may be with our last post from Jason who used the scientific name for Western Larch when he really meant to be referring to Subalpine Larch! We'll let him stick to running the organization). ANYWAY, today we are talking about the
Bald Eagle with the fancy name of
Haliaeetus leucocephalus. To decipher this we look to the Greeks where hali = salt, aeetus = eagle, leuco = white, cephalis = head. That's the white-headed salt eagle, or sea eagle as it is often called, but we'll stick to Bald Eagle today.
Have you noticed there has been a considerable increase in these big birds in the last week or so? In trees along the highway, in the rivers eating fish, flying low through the valley....yes, seasonal migration is on and eagles that spend their summers further north are returning here (their birth place) for the winter. (Some stay here year-round, but many more are here Nov-March).
Here's some info about Bald Eagles along with some local photos taken by yours truly:
Bald eagles historically occurred throughout the contiguous United States and Alaska. The largest North American breeding populations are in Alaska and Canada, but there are also significant bald eagle populations in the Great Lakes states, Florida, the Pacific Northwest, the Greater Yellowstone area, and the Chesapeake Bay region. In the fall, eagles begin moving to their wintering grounds, which can be throughout the US but mostly in the Midwest and West near open water and rivers, including the Methow Valley of course.
It takes 4 to 5 years for juvenile eagles’ mottled brown and white plumage to change to dark brown with the distinctive white head and tail. This is also when they begin to breed. See various stages of markings below.
Eagles mate for life, typically nesting in the tops of large trees; nests may reach 10 feet across and weigh a half ton. The birds travel great distances but usually return to breeding grounds within 100 miles of where they were raised.
Breeding bald eagles typically lay one to three eggs once a year, and they hatch after about 35 days. The young eagles are flying within three months and are on their own about a month later. Young are as big as adults when they fledge – they gain 10 lbs in 10 weeks.
Female adults may weigh 14 lbs and have a wingspan of 8 feet. Male eagles are smaller, as is the case in many birds, weighing up to 10 pounds with a wingspan of 6 feet.
Bald eagles are opportunistic feeders with fish comprising much of their diet. They also eat waterfowl, shorebirds, small mammals, turtles, and carrion. Here in the Methow we often see eagles eating dead deer on roadsides or over embankments. Because they are visual hunters, eagles typically locate their prey from a conspicuous perch, or soaring flight, then swoop down and strike. Eagles need to eat about 11 lbs of food a day in the winter. Note the bloody face (and feet) of this eagle that was recently feeding on roadkill deer.
At night, wintering eagles often congregate at communal roost trees, in some cases traveling 32 miles or more from feeding areas to a roost site. It is thought that communal roasting helps the birds communicate and find food.
To distinguish Bald and Golden Eagles at any age, the lower part of the bald eagle’s legs are bare. The entire legs of golden eagles are feathered. Golden are noticeably larger as well, but for more of us the birds need to be side by side for us to "notice."
Bald eagles may live 15 to 25 years in the wild!
On June 28, 2007, the US Fish & Wildlife Service removed the Bald Eagle from the list of threatened and endangered species, and deemed it “recovered.” The bird is still protected by the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act.
Happy Eagle Watching!
