Drought Could Take Toll On San Diego Bird Populations
Monday, February 10, 2014
Aired 2/11/14 on KPBS News.
Dozens of native species could face a tough spring if dry conditions persist.
On a winding path at Silverwood Wildlife Sanctuary in San Diego’s East County, a group of families, armed with walking sticks and binoculars, set off on a search for nature.
"Oh! I see a bird,” calls out Sylvia Busby, development and communications manager for San Diego Audubon Society.
Binoculars pressed against their eyes, the wildlife enthusiasts identify the bright blue bird.
“If anyone wants to see what we’re looking at, it’s this western scrub jay,” Busby announces, as she points to her bird book.
But the little bird and dozens of other native species could face a tough spring if dry conditions persist.
“If we go weeks again with no rain, it will be very much like 2002,” said Philip Unitt, curator at the San Diego Natural History Museum.
Unitt has studied the impact of drought on birds, as in 2002 when much of the county received just more than 3 inches of rain.
“The birds just didn’t nest when it was that dry,” he said.
Breeding season could be brief again this year, if it happens at all, Unitt said. His concerns extend beyond a few flocks.
Nearly 40 bird species build their habitats in the native shrubs of San Diego County. In a normal rain year, the plants would already be sprouting new growth by now.
“And there’s hardly any, and you can see a lot of the branches are dead,” said Unitt, bending down to get a close look at a chaparral shrub.
Fresh new greenery attracts volumes of insects — the primary food source for birds.
“But just the rain itself really stimulates them," Unit added. "So they don’t wait until they find there’s no food and they already have a nest of young. They won’t even try when it’s that dry.”
Instead, if they pass the window of opportunity to breed, they’ll move on to the next stage of their lives.
“Replacing their feathers, going through molt,” Unitt said.
In previous long droughts, the region experienced a change of some plants and animals. New species moved in to take advantage of changed habitats while others died back.
Unitt said there’s evidence of that happening in the Cuyamaca Mountains following the 2003 Cedar Fire.
“The mountain chickadee and pigmy nuthatch — two of the birds that were the most abundant in the Cuyamaca Mountains before the fire — were absolutely decimated and their recovery has been extremely poor,” said Unitt.
But some new species, drawn to the newly opened habitat, have responded positively and moved in – such as the lazuli bunting.
“A brilliant blue bird... is the biggest fire follower of all,” said Unitt. “And in Cuyamaca Rancho State Park after that burned almost totally in 2003, the next few years the lazuli bunting was the most abundant species.”
Unitt said drought-induced fires have caused an acceleration of changing ecosystems.
“We can’t regret evolution happening,” said Unit. “That’s like regretting the sun setting in the evening. But many of us perhaps were not prepared for this to happen at this rate in our lifetimes.”
It could be months or years before this drought’s impact on birds is fully understood, but Project Wildlife could get a first glimpse.
“I expect that there will be more stress on wildlife families,” said Beth Ugoretz, executive director of the wildlife rescue and rehabilitation group.
Last year Project Wildlife took in 8,000 wildlife creatures — most were baby birds. Ugoretz said this year, with the drought, it could be different.
“We might anticipate, perhaps, a slower season with births or fewer survivors of the babies that are born,” said Ugoretz.
She urged people who find abandoned or injured wildlife to bring it to the organization's triage center in Linda Vista.
Back at Silverwood Wildlife Sanctuary, children get a lesson on bird nests inside the visitor's center.
“And that’s a little tiny humming birds nest,” Busby explains to the children.
Come this spring, the avian architecture could be as rare as falling rain.