Members of the Audubon Society’s local chapters this week conducted their annual Christmas Bird Count in the Peninsula and Bay Area, amid concerns about how climate change and the drought are impacting the animals.
According to Golden Gate Audubon Society Executive Director Cindy Margulis, climate change and drought have taken a heavy toll on bird populations, reducing many species’ numbers, and forcing some to migrate to areas they don’t normally inhabit.
About a year ago, the National Audubon society released a study on how climate change affects birds, Margulis said, claiming when bird population data is compared to climate data, there appears to be a correlation between the changing climate and diminished bird counts.
“Birds in general are an important bio-indicator for our ecosystem,” Margulis said.
Some Peninsula towns, such as Pacifica and San Bruno, were included in the San Francisco count.
The San Francisco Examiner met up with Santa Clara Valley Audubon Society President Bob Hirt on Tuesday morning as he helped members of the organization’s Golden Gate chapter conduct bird counts in Pacifica.
Using handheld binoculars and tripod-mounted telescopes, the eagle-eyed bird enthusiasts worked in small teams, with one keeping count while another identified birds. In many cases, the birds were so small and well camouflaged, they might have escaped notice by all but the most seasoned bird watchers.
Walking a trail in Calera Creek Park, Hirt called the former rock quarry site a triumph of habitat restoration. The park, which links the Vallemar and Rockaway Beach neighborhoods, benefited from wetlands restoration about eight years ago, Hirt said, and the marshy environment gives numerous bird species a chance to thrive.
Hirt’s experience on Monday, counting birds on Santa Clara County’s Mt. Hamilton, provided less cause for optimism.
“The bird numbers were very low,” Hirt said, “We had hoped the drought was being partially rectified, but the results did not bear that out.”
The Lawrence’s gold finch is among the affected species, Hirt said, noting four years ago, his organization documented 394 individuals on Mt. Hamilton. On Monday, Audubon Society members counted just three.
The finches would normally feed on the mountain’s mistletoe, Hirt explained, but the drought has prevented those plants from producing the needed berries.
Another species apparently dwindling on Mt. Hamilton is Lewis’ woodpecker. While about 70 were confirmed four years ago, Hirt said this year’s count was a mere four.
A comparison of how Pacifica’s bird population has fared this year, compared to previous years, was not available at press time. But Joe Morlan, who participated in the count, said 95 species were confirmed in Pacifica, and the San Francisco count (including Pacifica and other North County towns) revealed at least 180 different species living in the area.
An ornithology teacher at City College of San Francisco, Morlan cautioned against putting an alarmist spin on shrinking bird counts, noting some species, like the dark-eyed junco, have increased their numbers in the Bay Area this year.
But Morlan acknowledged the low counts could be cause for concern. Just two American kestrels (a type of small falcon) were sighted in Pacifica this year, Morlan said, and their numbers seem to be “declining precipitously” all over the United States.
San Francisco’s Lafayette Park was home to a large population of varied thrush last year, Morlan noted. But this year, he said, the varied thrush was completely absent from that location.
Margulis said wetlands preservation and restoration is key to protecting many bird species from the effects of climate change. Shorebirds, such as the black oystercatcher, are particularly vulnerable to sea-level rise, Margulis said, and robust wetlands can act as buffers that protect the birds’ habitats from tidal surge.