On the wild side—March, 2013
by Tina Mitchell
A massive dark chocolate brown raptor with a golden glaze on the feathers of the nape, the Golden Eagle at 2 ½ feet tall dwarfs nearly all other raptors in our area, including Red-tailed, Rough-legged, and Ferruginous Hawks. More often seen soaring than sitting on a pole, its wings lift into a slight “v” shape (referred to as a dihedral). Although they inhabit primarily mountain canyons, rimrock, and grasslands, Goldens hang out along mountain rivers too, in part because of the rocky cliffs they provide. Pairs defend large territories—anywhere from 22 to 66 square miles, depending on the prey base and lay of the land.
A Golden’s diet consists mostly of small mammals, such as medium-sized ground squirrels (prairie-dogs and marmots rank among the favorites) and jackrabbits, although the young of larger mammals such as fox or deer sometimes show up on the menu. An occasional gamebird such as grouse and a few reptiles and fish round out the fare, making up about 15% of a Golden’s daily intake. Eagles have eyesight up to 8 times sharper than humans have, which allows them to easily spot even their smallest prey a mile away. During the winter, when snow drives deer and elk closer to roadways, Goldens function as the roadkill clean-up crew. Thriving on vehicle-killed carcasses, they can actually emerge from winter in better shape than at the end of breeding season. It’s a dirty job, but somebody has to do it…
The Golden Eagle’s scientific name—Aquila chrysaetos—emerged from the taxonomists’ Department of Redundancy Department. Aquila derives from Latin for “eagle;” chrysaetos, from Greek khrusos (golden) and aetos (eagle). Eagle golden eagle—not much of a story there. The common name extends the lack of creativity, since “golden” refers to the color of feathers on the head and neck and “eagle” comes from aigle (French) and, in turn, from Latin aquila, as noted above. Thus ends the redundancy dance.
A decidedly western species, Golden Eagles nest in a variety of habitats, with a strong preference for cliffs. In our area, the rocky cliffs along the Arkansas River provide at least 1 nest site for the resident pair. (Pairs often have more than 1 nest site in their vast territories.) Two essentials define a good nest site: sufficient space for an adult carrying prey to fly in without hindrance; and shelter from heat, cold, and precipitation. Golden Eagles exhibit strong fidelity to successful nest sites and apparently mate for life. They need a long breeding season, since incubation takes 43 – 45 days and the young fledge about 65 days after hatching. A typical clutch contains 2 eggs. Both parents incubate, although the female handles more of that duty. Once the young hatch, the female remains on the nest most of the time at first; the male brings prey to the nest for all to eat. If insufficient prey can be found, the adults feed the strongest nestling—which is usually the oldest—and only one survives. After about a month, the female leaves her constant vigil and joins in the hunting activities. Once the youngsters leave the nest, they can remain with the parents for as little as 1 month or as long as 6 months. However, once breeding urges stir, the parents will send the young birds on their way to find their own territories and mates. Since a Golden’s territory covers so much land, the next generation tend to disperse quite a distance from their natal area, if the parents staunchly defend their territory.
Golden Eagles are non-migratory in our area; so if you spot one high in the sky, it’s probably one of “the locals.” Goldens are the only North American representative of a large, worldwide group of eagles referred to as “booted” eagles, since they have feathers covering most of their legs. Bald Eagles, which winter in our area, belong to a different group, known as fish eagles (e.g., the Steller’s Sea Eagle)—so named because of their reliance on fish as a staple. While Bald Eagles rarely stray far from water and their preferred piscine food source, Golden Eagles work the skies of the mountains. John Denver captured this majestic raptor well: “I am the eagle, I live in high country/In rocky cathedrals that reach to the sky.”
You can see links to more photos and a clip of the call, as well as learn more, here.