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Undoubtedly, the best place in California to view migrating raptors is Hawk Hill. Hoping to view some impressive birds of prey, you grab your binoculars and head up to the hill. While you are scanning the skies for hawks, a cloud of tiny birds zooms into view, filling your binocular field. You desperately try to follow their zigzag flight, but it is nearly impossible to focus on one bird.
What are these tiny speed demons?
Most visitors probably do not know that Hawk Hill is also one of the best places to see swifts, a bird of prey in their own right. Swifts are small, aerial predators that dart through the skies, feeding on fast-flying insects. Though they superficially resemble swallows, the swifts have longer, more sickle-shaped wings, and their closest relatives are hummingbirds.
Unlike many small migratory songbirds, swifts migrate during the day and feed on insects on the wing. Indeed, these swifts provide a vital service for us humans. They devour annoying biting mosquitos and flies!
Three species of swifts pass through the Headlands on their fall migration, two of which can be regularly seen from Hawk Hill. Vaux’s Swift, the smallest of the North American swifts, is clad in a dull brown coat with a pale gray throat. This swift is the most likely to fly in large flocks of up to several hundred birds.
Vaux’s Swifts are declining in some areas because they nest in old-growth forests in the Pacific Northwest, not unlike Spotted Owls. Their specific wintering grounds remain unknown, but there are some populations that winter along the California coast. Others may winter in Mexico and Central America.
The other swift species seen commonly from Hawk Hill is the White-throated Swift. White-throated Swifts generally fly in smaller flocks than the Vaux’s, and make a chittery call. The most distinctively marked of the swifts, it has a bright white throat and white rump patches on either side of its tail.
White-throated Swifts are one of the fastest birds recorded, and they are more generalist in their habitat preferences, when compared to the other two species. White-throated Swifts winter from the Bay Area south to the Southwestern deserts.
The largest swift species seen from Hawk Hill is also the rarest—the Black Swift. True to their names, the Black Swift is completely jet black, with lower, shallower wingbeats than Vaux’s or White-throats. Black Swifts nest on cliffs in mountainous areas of British Columbia and the Sierras, often behind waterfalls. Their wintering grounds are completely unknown to science.
Although Hawk Hill is a raptor-watcher’s paradise, the lively flocks of swifts can be a highlight in September and October. Be sure to cast your binoculars their way!
By Robyn Smith
Former GGRO Intern
Photo: White-throated Swift by Dave Kutilek