A hike in Del Valle Regional Park in Livermore sent one of my colleagues to Raptors of California by Hans Peeters and Pam Peeters to learn more about the Osprey. With their conspicuous nests and distinctive features, Ospreys are fairly distinctive. Less easy to discover are some of the secrets of the raptor Pandion haliaeetus.

  • Like other raptors, Ospreys legs and feet are built to clench and
    lock around their prey, but it is fairly common for Ospreys to drown
    when they are unable to remove their feet from oversized aquatic prey.
  • Ospreys are ingenious builders. Peeters writes: “the species is
    famous for including all manner of odd building material, such as bits
    of plastic tarps, old flags, and Styrofoam cups.”
  • Ospreys show up throughout California, but particularly in Northern California. Ospreys are relatively new but now common species at Point Reyes. Ospreys may show up in odd places (Death Valley?!?) during migration.
  • Look for Ospreys by water. Their favorite food is fish, but they also eat frogs, turtles, and small mammals.
  • The Osprey is a California Bird Species of Special Concern. Scientists suspect pesticides such as DDT for its near disappearance in the 1960s.

There’s still time to see Osprey chicks–they usually don’t leave the nest until mid-summer.

A few quick links:
The Cornell Lab of Ornithology
Institute for Wildlife Studies
The International Osprey Foundation
Natural History of the Point Reyes Peninsula

Ornithological Monographs
Point Reyes National Seashore
Raptors of California

UC Berkeley Museum of Vertebrate Zoology