Wildlife workers released half a dozen birds that had been cleaned after an oil spill in the Bolsa Chica wetlands, even as they worried that the cold snap might kill the contaminated birds still out in the wild.
"Certainly it's gotten colder," said Scott Newman, a veterinarian with the state Oiled Wildlife Care Network. "The cold will put more of a stress on those birds that were not caught and cleaned. If oiled and still out there, it's difficult for those birds to maintain body temperature."
Spots of oil on a bird's feathers can act like a hole in a surfer's wetsuit. They allow water to penetrate the bird's natural covering, seeping into the trapped layer of warm air within the bird's feathers.
With their wings weighed down with oil, the birds can't fly and forage for food, so they run out of energy. They often die in out-of-the-way spots, found only by predators and never counted in the tallies of dead wildlife.
Since the spill was discovered Dec. 13, 22 birds contaminated with oil have been found dead. Of the 51 contaminated birds captured for cleaning, 14 died, said Robert Hughes, a state Fish & Game Department spokesman.
More than 30 birds have been cleaned and treated at the Wildlife Care Center in Huntington Beach and are expected to be released by Wednesday.
On Monday, the first batch, which included five coots and a pintail duck, was successfully returned to the wild in Upper Newport Bay.
"It went great," Newman said. "The birds flew away pretty much at the right moment right as we released them."
In contrast to Bolsa Chica, the Newport Bay was chosen because of its "pristine environment," Newman said, adding that the bay's 752-acre state preserve would provide a good new home for the birds.
"It's the same kind of habitat that they're used to in Bolsa Chica," Newman said. "In fact, most of their species are found here and we have no problems with environmental contamination."
He added that despite the cold, the birds' rehabilitation helped restore their natural insulation and that they should have no trouble with cold temperatures.
It is not clear who is responsible for the spill. Authorities determined that a Garden Grove public works yard was the site where 100 to 200 gallons of waste oil went into a nearby storm channel and traveled to the wetlands.
Videotapes from security cameras at the facility are being reviewed by police investigators. A city spokeswoman denied any city involvement.