Bald Eagle (Photo courtest Earl Harrison)
Bald Eagle (Photo courtesy Earl Harrison)
A magnificent adult Bald Eagle in a regal pose – Photo Earl Harrison

The scientific name means ‘whiteheaded sea-eagle’, which is quite appropriate given their appearancee and fondness for wide-open seashores and lakeshores. They’re part of a large group of sea-eagles, long-winged coastal birds quite different from the stockier Golden Eagles more common in arid inland areas of North America, Europe, and Asia. This is yet another avian apex predator (at the top of the food chain) that has been slowly recovering from the bioaccumulation of pesticides two to three decades ago.

2016 Audubon Photo Award: Bonnie Block - Bald Eagle Great Blue Heron
2016 Audubon Photo Award: Bonnie Block – Bald Eagle

Family: Accipitridae. This is the family of highly-specialized avian predators that includes accipiters, buteos, and eagles. Most of these birds swoop down from a circling soar or hovering position to grab their prey. Unlike most buteos, however, bald eagles rarely hunt from the air. Perhaps because of their size, they favor sitting on a prominent perch and swooping down on their target from there. They will often use their superb eyesight to scan for weak or injured animals, then launch out after them. Often it’s a fish sitting on the water surface, but more lively prey can include birds and mammals. Bald Eagles can be startlingly quick for a big bird; I once watched one chase down a twisting and turning Green-winged Teal in flight, grabbing it mid-air after a 7-minute chase. Their target also does not need to be alive; Bald eagles are scavengers par excellance, with a liking for dead fish. They often accumulate around areas where fish are dying, such as spawning runs or hydroelectric dams.

A Bald Eagle cruises over the Avid Birders at Magee Marsh
A Bald Eagle cruises over the Avid Birders at Magee Marsh

Field Marks: A huge long-winged bird of prey, eagles are almost unmistakeable after you’ve seen a few individuals. Their wings are long for their body, which results in a very wide soaring profile, as well as slow, deliberate flapping that is very different from the quick flaps seen in most other buteos and vultures. Turkey Vultures are the only similar bird, and their profile is different (smaller head, shorter wings) and they hold their wings in a slight ‘V’, unlike the flat-winged look of soaring eagles. Mature eagles are very distinctive with their pale white heads and tails. Juveniles are much more challenging to ID, since they often have darks heads and tails, with only some splotchy white on the underside of the wings to give them away. It takes at least 3 years for young eagles to mature, and birds in the process of maturing can have a bewildering mix of white and brown features, but still have the darkish body, big beak, and long wings of all bald eagles. As adults, females and males look identical except that females are 10-20% larger.

Range: Bald Eagles are exclusively found in North America, ranging from north-central Mexico north through all of the continental United States and Canada. Their favorite habitats are ocean bays, shallow coastlines, big rivers, and large lakes. They are most common along the Pacific Northwest coast, from Oregon north to Alaska; there, they are common sights, even in urban areas. The largest concentrations of Eagles gather along rivers in British Columbia and coastal Alaska during Salmon runs; the Chilkat River in Alaska has become especially reknowned for its large concentrations of eagles (2,000- 4,000 birds). A smaller population of Eagles exists along the Gulf and Atlantic coasts, from Texas through Florida and the Carolinas. These birds were able to persist in many of the river- and coastal swamp areas, which offered them some protection from disturbance or persecution. Inland, Bald Eagles are found sparingly in the upper Mississippi and Missouri River drainages, but are more common along rivers and lakes in Canada and the Great Lakes states. Most of these birds migrate south to winter along open stretches of the Great Lakes or the Mississippi-Ohio River system. Pacific birds don’t migrate much beyond moving up or down rivers. Fair numbers of migrant eagles can be seen at coastal sites like Cape May and Cape Charles, and a few interior sites, like Duluth in Minnesota or Lake Erie MetroPark in Michigan.

An immature Bald Eagle (Photo Rick Stelzer)
An immature Bald Eagle in flight – Photo Rick Stelzer

Mating and Nesting: Bald Eagles set up a large territory in the late Winter and defend it against other eagles. Courtship is one of the most spectacular among raptors, where soaring eagles will lock talons and pinwheel down for a hundred feet or more before disengaging. Possibly this allows potential mates to judge each others’ strength and courage. Pairing is for life, and the pair will build a large stick nest in a prominent site tree or cliff – on the territory. Since they are not secretive, it’s easy to notice these big birds prying dead branches from trees and carrying them off during nest construction, so this is often the first sign of nesting eagles. If successful, they will continue to re-use the nest, adding sticks until it becomes an enormous monstrosity. Many huge old eagle nests collapse their support tree, or weaken it so much that it blows down easily during a storm. The female lays 2-3 eggs, and they hatch asynchronously after an incubation of 34-36 days, which means that eagle broods have different-sized chicks. This acts as a cruelly efficient method to match eagle numbers with food resources. If the adults find enough food, all of the chicks will be well fed and reach fledging. If food is scarce, however, the older bird(s) will often outcompete and starve, or even directly attack and kill, their younger siblings. It takes 70-100 days to reach fledging, so the parents need about 4 months to complete a nesting cycle. It’s no wonder they often start nest building in the late winter.

Eagles in Central Ohio: Eagles have been ubiquitous up around the Western basin of Lake Erie for several decades now, so seeing one up there is easy. They’ve only become common here in central Ohio over the last decade. In winter, they favor the large mostly-open bodies of water in the area: Hoover Reservoir, Alum Creek Lake, Big Island Wildlife Area, Delaware Lake, O’Shaughnessy Reservoir, and the Scioto River around the Greenlawn dam. In summer, many of these areas now have nearby eagle nests; the nest southeast of Delaware Lake, in the Delaware Wildlife Management Area, has been actively reused for over a decade, and a nest up at Big Island has been in use for nearly as long. Eagles have steadily been moving into new nesting territories throughout the region. Within the past 2-3 years, so many ‘new’ territories have been reported that we seem to be getting swamped by immigrant Bald Eagles. Now there are at least three nests along the Scioto River between Circleville and Columbus, including a pair nesting in an old quarry just south of the Greenlawn dam. Another pair of birds has been frequenting the Three-Creeks area in Groveport, and a nest was found here within the past few weeks. Yet another nest has been reported from Highbanks Metro Park. With the number of eagles being seen in local areas, from the Darby Creeks to Newark, there seems little doubt that several more nests will be discovered this year.

Bald Eagle (Photo Jim Grey)
A Bald Eagle maneuvers in flight – Photo Jim Grey