The largest concentration of raptors in the Pacific States occurs over the Marin Headlands every fall when tens of thousands of hawks, falcons, and eagles are on the move. From August through December, volunteers from the Golden Gate Raptor Observatory spend their days identifying and counting raptors atop Hawk Hill. How do they know if the white-tailed kite that fluttered by at 10 a.m. was different from the kite that flew by at 2 p.m.? According to GGRO Director Allen Fish, “They don’t.” That’s why they refer to their count as “sightings” rather than actual birds. Through trial and error, they’ve even learned that not all raptors are migrating south, even though there are some that pass over the Golden Gate to points as far south as Argentina. The final count for autumn 2000 includes 25,231 sightings: turkey vulture (9,519), osprey (138), white-tailed kite (59), bald eagle (6), golden eagle (20), northern harrier (559), sharp-shinned hawk (2,476), Cooper’s hawk (1,998), northern goshawk (3), red-shouldered hawk (279), broad-winged hawk (89), Swainson’s hawk (4), red-tailed hawk (7,750), ferruginous hawk (23), rough-legged hawk (14), American kestrel (473), merlin (103), peregrine falcon (177), prairie falcon (3), unidentified (1,537). If you want to participate in the fall 2001 count, now is the time to sign up for volunteer training. For more information, log on to www.ggro.org or call (415) 331-0730.
Bay Nature magazine ◦ April-June 2001