Columns

WILD NEIGHBORS: Bird Atlases Lost and Found

By Joe Eaton
Friday February 03, 2012 - 09:59:00 AM

When the Alameda County Breeding Bird Atlas was published late last year, I wondered in print if anyone had undertaken, or was planning to undertake, a comparable project for San Francisco. It turns out that a San Francisco census was in fact completed some time ago, but the results have never been published. Thanks to a reliable source, I’ve seen the digital draft version. 

The data was collected in 1991 and 1992. A total of 103 avian species were documented, with 84 (81.6 percent) confirmed as breeding, 9 (8.7 percent) probable, and 10 (9.7 percent) possible. The mourning dove was the most widely distributed bird, followed closely by Anna’s hummingbird, American robin, and brown-headed cowbird. 

Since the city and county of San Francisco includes the Farallones Islands, the atlas covers such species as Leach’s and ashy storm-petrels, tufted puffin, Cassin’s and rhinoceros auklets, and common murre. San Francisco is also home to one of the Bay Area’s few coastal bank swallow colonies, the closest being the one at Ano Neuvo State Preserve in San Mateo County. Most of the state’s remaining colonies are along the Sacramento River. 

The compilers noted some interesting (in some cases ominous) trends. The sad story of the California quail, the state and city bird, is well known; they’ve almost been extirpated from San Francisco. Olive-sided flycatcher, Bewick’s wren, wrentit, and Hutton’s and warbling vireos were also declining. Common ravens were found in 55 percent of the atlas blocks; their distribution is almost certainly wider now. 

The draft also includes useful summaries of San Francisco’s ecological history (or historical ecology), plants, non-avian wildlife, natural communities, climate, geology, and geography. Before there was a city, there were grizzly bears, black bears, and mountain lions, and sea otters in the Bay. 

It would be good to have all this information available in print, even if the bird data is a little elderly. The Contra Costa and Alameda atlases both use survey data from the 1990s. I hope the San Francisco project has not been entirely abandoned. 

As it stands now, eleven California counties—Humboldt, Sonoma, Marin, Napa, Contra Costa, Alameda, Santa Clara, San Mateo, Monterey, Orange, and San Diego—have atlases in print. San Mateo’s is pretty basic—occurrence maps and raw observation data, but no text or illustrations. Santa Clara’s is telephone-book-sized. Some have outstanding art: Keith Hansen for Marin (and a couple of others), Dana Gardner for Contra Costa, Hans Peeters for Alameda, Sophie Webb for Napa. 

I have to admit that San Diego’s is the most impressive of the lot. It’s a hardback, with good photographs (by Tony Mercieca and others) of most of the covered species. And its coverage extends to wintering as well as breeding birds, which means that many species have two distribution maps. Winter coverage would be easier; you just have to see or hear the bird, as opposed to working through all the layers of certainty of nesting that the breeding survey requires. The winter reports also incorporate data from San Diego County’s six Christmas Bird Counts. 

A really splendid product, in short. Kudos to Philip Unitt, the project manager and lead author, and to the publisher, the San Diego Natural History Museum. An interactive version is available through Google Earth. 

When the Alameda County Breeding Bird Atlas was published late last year, I wondered in print if anyone had undertaken, or was planning to undertake, a comparable project for San Francisco. It turns out that a San Francisco census was in fact completed some time ago, but the results have never been published. Thanks to a reliable source, I’ve seen the digital draft version. 

The data was collected in 1991 and 1992. A total of 103 avian species were documented, with 84 (81.6 percent) confirmed as breeding, 9 (8.7 percent) probable, and 10 (9.7 percent) possible. The mourning dove was the most widely distributed bird, followed closely by Anna’s hummingbird, American robin, and brown-headed cowbird. 

Since the city and county of San Francisco includes the Farallones Islands, the atlas covers such species as Leach’s and ashy storm-petrels, tufted puffin, Cassin’s and rhinoceros auklets, and common murre. San Francisco is also home to one of the Bay Area’s few coastal bank swallow colonies, the closest being the one at Ano Neuvo State Preserve in San Mateo County. Most of the state’s remaining colonies are along the Sacramento River. 

The compilers noted some interesting (in some cases ominous) trends. The sad story of the California quail, the state and city bird, is well known; they’ve almost been extirpated from San Francisco. Olive-sided flycatcher, Bewick’s wren, wrentit, and Hutton’s and warbling vireos were also declining. Common ravens were found in 55 percent of the atlas blocks; their distribution is almost certainly wider now. 

The draft also includes useful summaries of San Francisco’s ecological history (or historical ecology), plants, non-avian wildlife, natural communities, climate, geology, and geography. Before there was a city, there were grizzly bears, black bears, and mountain lions, and sea otters in the Bay. 

It would be good to have all this information available in print, even if the bird data is a little elderly. The Contra Costa and Alameda atlases both use survey data from the 1990s. I hope the San Francisco project has not been entirely abandoned. 

As it stands now, eleven California counties—Humboldt, Sonoma, Marin, Napa, Contra Costa, Alameda, Santa Clara, San Mateo, Monterey, Orange, and San Diego—have atlases in print. San Mateo’s is pretty basic—occurrence maps and raw observation data, but no text or illustrations. Santa Clara’s is telephone-book-sized. Some have outstanding art: Keith Hansen for Marin (and a couple of others), Dana Gardner for Contra Costa, Hans Peeters for Alameda, Sophie Webb for Napa. 

I have to admit that San Diego’s is the most impressive of the lot. It’s a hardback, with good photographs (by Tony Mercieca and others) of most of the covered species. And its coverage extends to wintering as well as breeding birds, which means that many species have two distribution maps. Winter coverage would be easier; you just have to see or hear the bird, as opposed to working through all the layers of certainty of nesting that the breeding survey requires. The winter reports also incorporate data from San Diego County’s six Christmas Bird Counts. 

A really splendid product, in short. Kudos to Philip Unitt, the project manager and lead author, and to the publisher, the San Diego Natural History Museum. An interactive version is available through Google Earth.