Location
The GGRO programs center around Hawk Hill, one of the highest points (940 feet elevation) immediately above the Golden Gate on the north sides, in Marin County. This publicly accessible site, a center-point 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.
While 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. A preference for flying over land keeps many hawks from readily flying over open water. Consequently, many raptors end up flying over Hawk Hill as they negotiate the two-mile gap to San Francisco, creating a raptor migration thoroughfare.
Visiting
Limited parking is available at the base of Hawk Hill. Visitors can walk a short (0.15 mile), but steep route or take a longer (0.25 mile), less steep path to reach the summit of Hawk Hill.
Migration season
To track the fall migration, the GGRO starts its programs annually in mid-August and ends them mid-December. At the migration's peak in late September/early October, as many as 1,000 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 an average of nineteen raptor 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.
Migration timeline
| Species | Peak Migration Time | Average # of Sightings/Year (2003–2014) |
|---|
| Red-tailed Hawk | September and November | 8,947 |
| Red-shouldered Hawk | September–October | 463 |
| Broad-winged Hawk | Mid-September–Mid-October | 215 |
| Rough-legged Hawk | November | 6 |
| Swainson's Hawk | September–October | 7 |
| Ferruginous Hawk | September–November | 21 |
| Cooper's Hawk | September–October | 2,435 |
| Sharp-shinned Hawk | September–October | 3,945 |
| Northern Goshawk | October–November | 1 |
| American Kestrel | August–December | 482 |
| Peregrine Falcon | Late-September–December | 237 |
| Prairie Falcon | August–September | 6 |
| Merlin | October | 178 |
| Osprey | August–Mid-October | 93 |
| Turkey Vulture | August–December | 8,434 |
| Northern Harrier | October–December | 618 |
| White-tailed Kite | October | 97 |
| Golden Eagle | Late-September–October | 18 |
| Bald Eagle | Late-October–November | 6 |
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