A bird in the hand is worth two in the bush -- at least when it comes to counting the wide range of bird species that spend their winters in San Francisco.
More than 100 seasoned bird-watchers are set to scour the San Francisco Bay and its environs Tuesday for the Golden Gate Audubon Society's 29th annual Christmas Bird Count -- a census-like count assessing the state of the
Bay's bird life, said Dan Murphy, who co-founded the local event.
Teams of bird watchers from dawn to dusk will peer through binoculars to count birds in 17 different San Francisco locations including a boat that will span the Bay, according to Murphy.
Sponsored in part by the Presidio Trust, the Christmas count coincides with more than 2,000 bird compilations this month taken throughout North and South America and in some Pacific islands, he said.
"Birds are a lot more accessible in winter," Murphy said, making the holiday season an ideal time to catalog both native and far-flung winged creatures.
During last year's holiday event, observers in San Francisco counted 177 different bird species and more than 57,000 individual birds, ranging from pigeons to more exotic species such as the red phalarope, the Tennessee warbler or the black-legged kittiwake.
But participants last year also noticed a startling lack of other previously native bird species such California Quail and different types of diving ducks.
Murphy said San Francisco's bird populations appear to dwindle due to air and water pollution and because of rising numbers of feral cats and off-leash dogs that prey on various birds.