August 1, 2011
If you had taken a walk through Golden Gate Park in 1930, you would not have seen a single Pigeon. The European Starling had not yet made its way to the park. The California Academy of Sciences Handbook of Birds of Golden Gate Park, published that year, stated definitively that “no Raven had ever been reported in the Park.” Crows were extremely rare, and herons and egrets would have been almost impossible to find, barely having escaped extinction after being shot by the hundreds of thousands nationwide so that their plumes could be used for hats.
Golden Gate Park employed a hunter, who systematically killed hawks, jays and other birds considered to be pests. Red-Shouldered and Red-Tailed Hawks, now common, were almost impossible to find.
But what you would have seen in abundance in 1930 is the bird that is now the City’s (and the state’s) official bird, the California Quail. Once numbering over 1,200 birds in Golden Gate Park alone, today only a handful remain, and almost the only place you can find them now in the City is still in Golden Gate Park, at the San Francisco Botanical Garden. Feral cats and other predators have decimated this once common species.
Although threatened in San Francisco, the California Quail thrives elsewhere. Quail nests can contain up to 28 eggs, and quail families often gather together communally, with all the parents looking after all the offspring. The distinctive head plume, or topknot, which makes quail identification easy, is actually a collection of 6 overlapping feathers.
Quail couples sing duets, with a male and a female calling alternately. They are well-adapted to arid climates, and get much of the moisture they need from insects and vegetation.
As we continually alter the landscape of the City, the birds we see gradually change. Just as San Francisco is home to many human immigrants, there are immigrants of the avian variety as well. New bird species immigrate into the City, while others expand their populations, and some decline or vanish.
The latest avian species to immigrate into San Francisco is the Eurasian Collared Dove. This adaptable native of Sri Lanka, India and Myanmar has spread around much of the world and was introduced into the Bahamas in the 1970s. A decade later ornithologists in Florida observed an explosion in the population of what they thought were Ringed Turtle Doves, but what turned out to be Eurasian Collared Doves. From there they have spread relentlessly westward – reaching California in 2002, and San Francisco in 2004.
The most intriguing theory about these doves is that they fill an ecological niche vacated by the Passenger Pigeon, once the most abundant bird on the planet with an estimated population of 5 billion birds, but wiped out entirely by humans in the 19th century. When Europeans first arrived in North America, there were more Passenger Pigeons than all other birds on the continent.
The scientific name for Eurasian Collared Dove is Streptopeleia decaocto, which means a collar (streptos) and dove (peleia). In Greek mythology, Decaocto was an overworked, underpaid servant. Hearing her prayers for help, the gods changed her into a dove so she could escape her misery. The dove’s mournful call is said to echo memories of her former life.
There has been concern that the Eurasian Collared Dove might compete with, and displace, the native Mourning Dove, but so far that doesn’t appear to be happening. Mourning Doves benefit from the vegetation, particularly undergrowth, that has been planted in San Francisco parks. They are hearty eaters, eating up to 20% of their body weight in a single day. Mourning Doves store seeds in an enlargement of the esophagus called the crop before flying to a perch to digest the collected food. According to the Cornell Laboratory of Ornithology, one Mourning Dove was observed to have collected more than 17,000 bluegrass seeds in its crop before digesting its huge meal.
The Mourning Dove is the most abundant game bird on the continent. Even though hunters shoot more than 20 million of them a year, there are still an estimated 350 million in the U.S. They are also long-lived, with at least one record of a Mourning Dove living to the age of 31.
Another relatively recent immigrant to the City is the Red-Masked Parakeet, popularly known as the Parrots of Telegraph Hill. The 200-plus parrots are descended from a small group of escaped wild parrots that were wild-caught for the pet trade in South America in the 1980s. These colorful, raucous birds are spreading across San Francisco, benefiting immensely from gardens in the City that provide them with more than adequate amounts of food (augmented, unnecessarily, by food put in bird feeders). Although their population is expanding, they are preyed upon by Red-Tailed Hawks.
While some birds move into the City, others just expand when they are no longer hunted. That’s definitely the case with raptors, such as hawks, that used to be shot on sight. Cooper’s Hawks, once rare, are nesting in the City again, and the owl population is booming. This summer I observed six Great Horned Owls in one afternoon on Strawberry Hill at Stow Lake in Golden Gate Park, which is more than were reported from Christmas Bird Counts in the entire first half of the 20th century in all of San Francisco.
Great Horned Owls nest throughout the City, and Barn Owls seem to making a comeback as well. Last month, three Barn Owl nests were discovered at the Exploratorium, holding at least 11 owls.
Sometimes the change in species is gradual. Pacific Wrens, for example, generally residing in forests, found San Francisco inhospitable before humans started planting trees in the City. A hundred years ago, the average Christmas bird count would have recorded one or two Pacific Wrens. Now the count is typically between 30 and 40.
These small birds, usually about 4 inches in length, deliver a complicated and surprisingly loud song. Proportional to its size, its song is 10 times as loud as a crowing rooster. The song is also amazingly complex, with 36 notes per second. I’ve often tried to track down what I thought to be 3 or 4 singing Pacific Wrens, only to find that all the songs are coming from one bird.
California Towees have expanded even more dramatically with annual counts expanding from almost none in the first half of the 20th century to more than 300 each year in San Francisco. They like vegetated backyards and parks, both of which are now in good supply in San Francisco. Essentially a large brown sparrow (they used to be called Brown Towee), these birds have an orange patch under their tail, which isn’t always visible.
California Towees are especially fond of poison oak berries, and like to nest in poison oak. They will also nest in ornamental shrubs and trees and in Eucalyptus trees. They like to eat berries, seeds and insects.
The beautiful Spotted Towee, on the other hand, has declined dramatically in the City, and can now only be found reliably in the western side of the Presidio above the ocean, and on Bayview Hill. Once so common that they were known as the San Francisco Towee, Spotted Towees like open shrubby habitat, most of which has disappeared. Male Spotted Towees love to sing at the top of shrubs in the spring, and may spend up to 90 percent of their mornings singing, hoping to attract a mate.
Despite all the ongoing changes in bird populations in San Francisco, the City continues to attract, and provide habitat for, a diverse group of amazing birds. As I write this, the number of bird species that have been spotted in San Francisco this year stands at 262, proving once again that San Francisco is a hub of avian diversity. I consider myself fortunate to have seen 195 of these species this year.
© All pictures were taken by David Assmann, Deputy Director of the San Francisco Department of the Environment. Do not reproduce pictures without permission.