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The GGRO is a cooperative program of the Golden Gate National Parks Conservancy and the National Park Service.
The GGRO is proud to be supported by:
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The following questions and answers are those that are most often asked of us. If you do not see an answer to your question, please feel free to contact us.
Why are raptors important?
Raptors are generally near the tops of food pyramids, so their population health depends on the health of the populations that they feed upon. Declines in those prey populations can indicate some fundamental problem in the specific ecosystem where that raptor species resides.
What is migration?
Bird migration is the annual movement of a population between its wintering and breeding grounds. Some of the raptor migration seen at the Golden Gate may be simple and regular like this, while some of the raptor movements we witness are more complicated and less directional. Biologists refer to these more ecological movements as “dispersal.”
Do hawks feed on migration?
Most hawks stop and hunt during the migration season. Ornithologists are just starting to learn about these "stopover" sites and their importance to a bird's survival. However, some long-distance migrant raptors, such as the Swainson's Hawks, may go for a month or more with no apparent feeding while migrating from Saskatchewan to Argentina. It’s believed that these birds survive this arduous trip on stored fat, which they build up before setting off.
What is the GGRO: a place? A group?
The Golden Gate Raptor Observatory is a long-term program of the non-profit Golden Gate National Parks Conservancy in cooperation with the Golden Gate National Recreation Area (National Park Service). The GGRO consists of three staff, four fall interns, and 250+ amazing volunteers all dedicated to the monitoring of the raptor migration over the Marin Headlands. The place we conduct most of our studies is the Marin Headlands. Hawk Hill in the Headlands is the best place to observe the fall migration.
Do you have a visitor center? Can we see hawks in captivity?
We do not have a GGRO visitor center, but the Marin Headlands Visitor Center, near Rodeo Lagoon, has a great display about the migration and the birds of the Headlands, as well as great raptor books. Our chief goal is to get you to come to Hawk Hill to see the real, live hawk migration. We do not have any captive hawks, but recommend Wildcare (San Rafael), the Lindsay Museum (Walnut Creek), the California Raptor Center (Davis), or the SF or Oakland zoos as excellent places to see captive hawks close-up.
What kind of binoculars are best for watching hawks? How about spotting scopes?
Seven, eight, or 10 by 40-to-50 allow for good magnification and let in enough light to see field marks. Better magnification is valuable, until it creates an image that is too dim or too shaky. Generally it’s wise to buy binoculars from a familiar optics company. Scopes are difficult to use at a raptor migration site unless you already have a lot of skill with your own scope and tripod. If you are good at using a scope to find distant hawk dots in the sky, and at panning as the hawks fly by, then sure, bring one to Hawk Hill. But make sure to set up away from human traffic so that your tripod doesn’t get bumped, and use a small wide angle lens if you have one, a 20 or a 25 wide angle.
Is Hawk Hill a good place to do some hawk photography?
My feeling is that it is not, and here’s why. First, the mid-day light – when the hawks are flying -- is bright and unfiltered by trees, so most of your hawk shots will be overly dark as your camera compensates for the bright sky. Secondly, on a great Hawk Hill weekend day, we may be host to several hundred people, some birding, some with cameras, and jostling for a good spot can be frustrating. On the upside, if you come out to the Marin Headlands and cruise the roads and trails early or late on an autumn day, you are bound to run into some migrating raptors perched or roosting. The light will be better, as will your photos, but please don’t flush these already migration-weary raptors.
What are the best field guides for hawks? Where can I get them?
Allen Fish's opinion is that the best all-purpose field guide is the Peterson Guide to Hawks by William S. Clark and Brian Wheeler. Second best is Jerry Liguori’s Hawks from Every Angle. Also excellent are Hawks in Flight by Pete Dunne, David Sibley, and Clay Sutton; and the Wheeler Guides by Brian Wheeler. For great behavior and ecology of western raptors, dive into Raptors of California by Hans and Pam Peeters. All four of these guides can be purchased at the Marin Headlands Visitor Center.
Do they band or count hawks anywhere else?
There are many other hawk watches and banding stations around the world, but ours is unique due to 1) the close working alliance between hawk counters and banders, and 2) the great degree of volunteer involvement and leadership (50,000+ hours per year). Cape May in New Jersey and Hawk Mountain in Pennsylvania are both home to well-known hawk watches and banding sites. The greatest raptor flight in the world is at Veracruz, Mexico, and is monitored by our colleagues at Pronatura Veracruz. See our LINKS list for more raptor migration stations.
Is there a spring migration in the Marin Headlands?
Yes, in recent years, GGRO volunteers have located a springtime, largely-northbound flight of raptors through the Marin Headlands. Although the mix of species is similar as in the fall, the magnitude is about one-third of the fall flight, or 18 raptors per hour. The season is late February through early May.
What happens to GGRO data?
The GGRO HawkWatch is a long-term scientific data-collection program. In order to accurately reflect population trends we need many years of data. At this point in time we can speculate about short-term population trends and correlate our data with other hawkwatch count sites to look at larger trends. In the meantime, we annually share data with the USGS, the USFWS, the National Audubon Society, the Hawk Migration Association, the California Department of Fish and Game, and with others looking at raptor numbers and trends. We get regular requests from researchers and agencies for subsets of our data.
A synopsis of our fall migration data are published annually in our own newsletters and sent widely to raptor and avian biologists around the country. Since 1984, we have published more than 20 scientific articles and reports, and given more than 50 scientific presentations.
Where do you get your funding?
The Golden Gate Raptor Observatory is funded by the Golden Gate National Parks Conservancy, the National Park Service, and generous donations from private individuals and corporations. If you’d like to support our work, we’d be delighted to have your help.
Is it legal to pick up and keep raptor feathers?
It is illegal to keep any native bird feathers. This policy is designed to prevent people from harming or interfering with raptors for the sake of their feathers. It also keeps feathers from becoming sellable. Native Americans are permitted to possess raptor feathers for spiritual use. Scientists and educators may obtain permits to keep feathers for their profession.
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