| Founded | 1985 |
|---|---|
| Location | Bldg 1064, Fort Cronkhite, Sausalito, CA 94965 ggro@parksconservancy.org 415-331-0730 |
| Key people | Director Allen Fish Research Director Buzz Hull |
| Mission | Monitoring Pacific Coast Raptor Migration |
| Volunteers | 280+ |
| Employees | 3 |
| Website | www.ggro.org |
The Golden Gate Raptor Observatory (GGRO) is a non-profit organization whose mission is to study migrating birds of prey along the Pacific coast and to inspire the preservation of raptor populations in California. Established in 1985, it is a joint program of the Golden Gate National Parks Conservancy and National Park Service, and is located in the Marin Headlands, just north of San Francisco, California.
The GGRO programs center around Hawk Hill, one of the highest points (940 feet elev.) immediately above the Golden Gate on the north side, in Marin County. Discovered as the most productive hawk migration site in California by ornithologist Laurence Binford in 1972, Hawk Hill was called Point Diablo early on. This publicly-accessible site, a centerpoint of the Golden Gate National Recreation Area, offers visitors a spectacular vista of the San Francisco Bay Area, as well as the best view of the autumn hawk migration. At the migration's peak in late September/early October, as many as 800 raptors a day may be counted overhead.
The Golden Gate migration is primarily one of diurnal raptors — hawks, kites, falcons, eagles, vultures, osprey, and harriers — with nineteen falconiform species appearing annually. In addition, a small range of non-raptorial migrants appear over the Marin Headlands in the autumn; this includes three species of swift, six species of swallow, and Band-tailed Pigeons, among dozens of avian species.
The GGRO is one of the few bird research stations in the country where a raptor-counting program and a raptor-banding program operate in the same organization. Started by National Park Service biologist Judd A. Howell, and volunteers S. Williston Shor and Carter L. Faust in the early 1980s, the Raptor Observatory today still operates under the philosophy that incorporating citizens into the process of gathering scientific data will deepen long-term conservation results. Consequently, the organization’s small staff is augmented by the work of 280+ highly trained volunteers, coming from all different disciplines. The GGRO publishes an annual report, contributes annual results to national databases, and collaborates on various research projects with local universities.
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The GGRO has three ways of monitoring the fall migration of raptors: hawk counting (Hawkwatch), hawk banding, and radio-tracking (Telemetry).
The Marin Headlands are a raptor migration thoroughfare. Many raptors migrate south from their northern or higher altitude nesting areas to find better sources of prey during fall and winter.
While on migration, birds of prey use air movements, such as rising thermals and updrafts on wind-facing hills, to maintain their altitude. A preference for flying over land keeps many hawks from readily flying over open water.
Moving toward the Marin peninsula's southern tip in the Headlands, the "front" of migrating raptors is squeezed by San Francisco Bay on the east and the Pacific Ocean on the west. Many end up flying over Hawk Hill as they negotiate the two-mile gap to San Francisco.
To track the fall migration, the GGRO starts its programs annually in mid-August and ends them mid-December. The organization offers public "Hawk Talks" and banding demonstrations during clear weekend days in September and October on Hawk Hill.