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Earth Dr Reese Halter's Blog

NATURE'S BLUEPRINT

bald eagles along the Pacific coast in January

Story ran in Malibu Times, November 9, 2012

Eagles are born to soar. They rule the sky over mountains, scrubland, lakes and oceans’ edges. Both bald and golden eagles grace the West and once upon a time the Santa Monica Mountains, California.

Raptors, birds of prey, specialize in hunting and eating meat. They have dagger-clawed feet called talons that are designed to grasp and pierce. Their hooked beaks are suited to tearing carcasses a part.

They have binocular vision, eyes oriented towards the front rather than the side, which are five to six times stronger than humans’. They are routinely able to spot small mammals a mile from the sky.

The eagle’s ability to soar is legendary. They are experts at reading landforms and finding updrafts and thermals – those spiraling columns of warm air that rise to considerable heights and are often topped by cumulus clouds.

Both golden and bald female eagles are slightly larger than the respective males. Females weigh 13 pounds and males reach 10 pounds and both have 7.5 feet wingspans. They are the largest raptor in North America.

The golden is known for its special excellence of flight and is named after its regal mantles of feathers on its crown and neck. Its feathers extend right down to its toes. Bald, like other sea-eagles, have bare legs.

Golden eagles are synonymous with the high country. In the West they migrate south as far as New Mexico. Their main food source is rabbits, hares, grouse and carrion, though they eat marmots, ground squirrels, moles, mice, skunks, weasels, badgers, herons, hawks, coots, ducks, magpies, fish and snakes. A breeding pair requires about 705 pounds of live weight food each year.

They hunt with cat-like surprise with one in five attacks successful.

Bald eagles, with their white heads and tail feathers, can often be seen on a commanding perch along shores of oceans, rivers and lakes – searching for fish. They also rely upon waterfowl and carrion for sustenance. As long as there is open water these spear fisherman will swoop, snatch and return.

Sometimes bald eagles will plunge into water. If they become waterlogged, they will swim, using the butterfly stroke, ashore.

Bald eagles have huge treetop nests, 8 feet across and 12 feet high, weighing two tons. Golden eagles prefer nesting on cliffs. Both species build their nests with sticks carefully woven into place with their bills.

Clutch sizes range from one to three eggs. Usually only one golden chick survives, as it kills its other sibling(s). Eagle chicks add about 1 pound every four or five days, reaching full size after 10 weeks. Only 50 percent of bald eagles survive their first winter and its even lower for golden eagles.

Eagle populations markedly declined during the 20th century. They have been shot at, poisoned and electrocuted; yet they have proven adaptable and resilient.

I’ve seen bald eagles locally in Sycamore Canyon; I’d like to see golden eagles re-introduced into the Santa Monica Mountains as a part of sensitive land planning and careful wild fish stock management. We have so much to learn from these aerial apex-predators. If we use poison, belch toxins and sully our fresh water, we kill the magnificent eagles. Sooner rather than later that toxicity will kill humans, too.

Australia, Radio 1, National: Ockham’s Razor — The War Against Nature

Earth Dr Reese Halter is an award-winning broadcaster and distinguished conservation biologist. His latest book with Chris Maser is Life, The Wonder of it All

Text © Dr Reese Halter 2014. All rights reserved.

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