OSPREYS GET BUSY
Watch our fascinating fish hawks fish, fly, and fledge
True to the season, o’er our sea-beat shore,
The sailing osprey high is seen to soar,
With broad unmoving wing, and, circling slow,
Marks each loose straggler in the deep below;
Sweeps down like lightning! plunges with a roar!
And bears his struggling victim to the shore.
Okay, it might be a bit hokey and overblown, but this stirring snippet from T.A. Conrad’s poem Fish Hawk (Osprey) does shed light on one of our park’s most eye-catching raptors—the osprey. Almost wiped out by DDT in the 1960s, ospreys have made a remarkable comeback, and are now a common sight throughout the San Francisco Bay region.
Hang out at China Camp and you’ve got a good chance of seeing—and hearing—these fascinating birds of prey. First, listen for the osprey’s call: a piercing whistle, sometimes with a descending trill. Scan the skies: If you see a large, lanky raptor, its wings bent with a distinctive crook (not flat like most hawks and eagles), you’ve found an osprey.
The osprey’s whitish head and tail may make you think you’re seeing a bald eagle, but the osprey (Pandion haliaetus) is much leaner and smaller—wingspan is typically five feet for an ospreys, six to seven feet or more for a bald eagle. That bend in the wing is another clue that it’s an osprey, not an eagle.
Something fishy this way comes
Ospreys are incredibly adept at catching fish. The birds circle or hover over open water, using their specialized lenses (similar to your sunglass’s polarized lenses) for spying prey below the surface. Once an osprey sees a fish, the bird descends rapidly with long legs thrust forward and talons extended to grab its prey. According to the National Wildlife Federation, osprey have an impressive success record—one in four dives or less typically yields a fish.
Another impressive fact: Ospreys can swivel one of their four toes on each foot backwards (two in front, two in back). This helps them get a better grip on slippery, wiggly prey. On its way back to the nest or perch to eat, an osprey can adjust its grip so that the captured fish is aerodynamic, making it look a bit like a dangling weathervane or ship’s keel.
Ospreys nest in our area, returning to their nest in mid-March or April. Preferred nesting site is a lofty perch (such as the top of one of the numerous PG&E towers in and around the park), with good sight lines and near a large body of water.
From eggs to gawky teenagers
Three or four eggs usually hatch a few days apart in a little over a month, with fledglings ready to stretch their wings about a month and a half after they hatch. Not all make it, particularly if some chicks hatch later and have a hard time getting enough food to survive.
Watching young ospreys fledge makes for entertaining viewing, with the young birds looking every bit the gawky teenagers as they stand on the nest’s edge and flap their long, slim wings. Even after they get the hang of flying and can catch their own food, juvenile ospreys often return to the nest to roost. The nest typically goes silent fall through winter.
To follow birds that nest in our region, check out these osprey web cams. For more information on ospreys, visit Golden Gate Audubon Society’s osprey website.