Winter Raptors: Bald Eagles on California's Prairie

Winter is a great time to see raptors in the wilds of California - particularly in the patches of grassland and prairie that remain in the Central Valley and adjacent foothills.  A few days ago, while searching for winter raptors like Ferruginous Hawks and Rough-legged Hawks (both of which we found), we happened upon four Bald Eagles (as well as two Golden Eagles).  Two of the Bald Eagles were adults, with snowy white heads, and the other two were immature birds, as evidenced by their mottled brown-and-white appearance.  It takes five years for a young Bald Eagle to develop the characteristic white feathers on its head.

Immature Bald Eagle

While Bald Eagles (Haliaeetus leucocephalus) breed largely in the north, in forested areas near bodies of water, during the winter they are found across much of the United States, always near water.  Look for them near lakes, reservoirs, rivers, coastlines and at many of our National Wildlife Refuges.

Mature Bald Eagle

The Bald Eagle is one of North America's great conservation success stories.  These majestic, symbolic birds began to decline rapidly during the mid-1900's as a result of shooting, trapping, poisoning and DDT-related reproductive failures.  In 1978, Bald Eagles became protected under the Endangered Species Act, and since 1980 their numbers have steadily increased, thanks in large part to the banning of DDT, a nasty pesticide that causes weak eggshells and early death of eggs before they hatch.  

Bald Eagle populations have recovered sufficiently enough to warrant their removal from the Endangered Species list in 2007, but the large scavengers still face a handful of threats: lead poisoning from ingesting ammunition embedded in the carcasses of animals shot by hunters, exposure to oil from spills along coastal habitats, and general loss of shoreline habitat are among the largest dangers to Bald Eagles today.

Moody skies and fading fog over a patch of California's prairie, winter habitat for eagles and other raptors.

Comments

Post a Comment

You Might Also Like:

Birds of the Desert: Residents & Spring Migrants

Image
Nearly everyone knows the desert as a barren, desolate land of extremes: high heat, low precipitation; little available food and water; prickly, spiny, unfriendly plants growing in a sea of rocks and sand as far as the eye can see.  But for those who stop and look closer, the desert reveals itself as the beautiful, incredible, mesmerizing place it truly is, teeming with unexpected life. Juvenile male Costa's Hummingbird visiting chuparosa blooms next to our campsite in Anza-Borrego Desert State Park. I particularly love the desert in the spring, when the annual wildflowers, cacti, flowering trees and shrubs are all in bloom.  (I've experienced the desert in the searing 120 degree heat of summer, and the rainy, even snowy cold of winter... and spring wins every time!)  Eric and I just returned from a week in the Colorado desert, exploring the imperiled, accidental Salton Sea (more on that coming soon), the vital wetlands of the Sonny Bono Salton Sea National Wildlife Refu
Read more

A Shorebird Primer: Godwits, Curlews, Willets and Whimbrels

Image
For those of us living in the Great Central Valley, autumn is the time to head to the coast.  Of course, there is no bad time to visit California's magnificent coastline.  But as the heat and haze of summer drag on in the Valley, the sea becomes increasingly tantalizing: September and the onset of autumn bring sunny weather and an abundance of migratory seabirds and shorebirds to our coast. A new birder visiting California's Central Coast will undoubtedly be met with a splendid array of very confusing birds.  Among these are small shorebirds like  "peeps" (sandpipers), Sanderlings and various  plovers .  But the larger birds can be just as confusing, until you learn a few distinguishing features.  Four large shorebirds that are commonly seen (and commonly confused) along California's Central Coast are Godwits, Curlews, Willets and Whimbrels. Marbled Godwit (upper left), Whimbrel (upper right), Long-billed Curlew (center front) The distinguishing featu
Read more

Birding in Adverse Weather Conditions: Wind and Rain

Image
Though I often extol the virtues and merits of winter in the Central Valley , especially when it comes to birding, the whole truth is that we experience "bad" weather also, just like anywhere else.  But even when the winter weather rolls in, the birds are still out there!  And sometimes, despite our best planning efforts, a birding day happens to coincide with crummy weather.   In that case, what's a birder to do?  Usually, we go birding anyway!   Birders far more intrepid than I regularly brave the ice and snow of northern winters to see their favorite birds, so perhaps you should look to them for real tips on winter birding!  For those of us in the valleys of California, the worst weather we see - wind and rain - is really comparatively mild.  Birding on an extremely windy day! I don't know of anyone who actually likes birding in the rain.  But I would argue that birding in the wind is just as aggravating as trying to bird in the rain!   Wind can be utterly infuri
Read more

What's Wrong With This Tree?

Image
If you've spent any time in an oak woodland (and I sincerely hope that you have!!) you may have noticed something odd: strange growths on the branches and leaves of oak trees.  You might wonder if the trees are sick or diseased, or plagued with a dangerous pest. But not to worry; these fascinating growths are a normal part of a healthy oak community.  Spined Turban Gall on Valley Oak, with a bonus gall: the tiny orange sphere to the left of the larger gall might be a gall of the California Jumping Gall Wasp (inconclusive) These growths are in fact galls, and are caused by a variety of cynipid wasps.  Galls form when a wasp lays eggs in a plant's tissue, releasing chemicals which stimulate the plant to use its own tissue to form protective structures around the eggs.  As the insect larvae develops, it feeds on plant tissue from within its cozy gall home.  Galls form on a variety of plants, including alders, poplars, willows and even sagebrush.  But the best known and m
Read more

Joshua Tree Woodlands: A Tale of Sloths, Moths and the Trees that Need Them

Image
In 1844, early California explorer John C. Fremont gave a somewhat scathing review of Joshua trees when he wrote, "...their stiff and ungraceful form makes them to the traveler the most repulsive tree in the vegetable kingdom."  Rather unkind, don't you think?  But when Joshua trees were formally described by scientist William Trelease in the 1890's, he noted that Joshua Trees are "the most attractive of all the Yuccas."  I am inclined to agree with this sentiment, and must disagree most heartily with Lieutenant Fremont! I, for one, adore Joshua Trees, with their whimsical shapes and great ecological significance!  If you struggle with plant identification, the iconic Joshua tree, hallmark of the Mojave Desert, is a good place to start.  With densely spiked tufts protruding from the ends of gangly arms stretched towards the heavens, this looks like a plant straight from a Dr. Seuss book.  Native people called these trees “humwichawa,” and used thei
Read more

Invasive Species: European Beachgrass

Image
Visit a beach in California, particularly in the northern half of the state, and you are likely to come across stands of European Beachgrass ( Arundo arenaria ).  It looks so innocuous, picturesque even, waving in the Pacific breeze and blurring the line between land and sea.  But this grass, a plant you've probably never thought twice about, is much more than it seems.  Innocuous it is not.  European Beachgrass is one of California's most wanted offenders: an introduced, aggressive invasive species. This picturesque photo of the California's Pacific Coast has a secret...  Most people won't notice that the grass seen here is an imposter; it's not native to the area, but a species that doesn't belong in this ecosystem. The main crime this grass is guilty of is being too good at its job.  In 1869, European Beachgrass was planted around Golden Gate Park in San Francisco, and since 1900, it has been introduced to other parts of California's coast in an
Read more