Cleanup of Oil Spill Nearing Completion : Accident: Workers mop up along Los Angeles River after Wednesday’s three-truck crash. Search continues for smeared birds.

More than 80 state workers spread out along the Los Angeles River on Thursday, trying to mop up an oil spill caused by a multi-truck collision Wednesday, as the search continued for birds fouled by the spill.

“We’re about ready to stick a fork in it,” said Lt. Marc Caywood of the Department of Fish and Game, surveying cleanup efforts from the command post in Balboa Park. “That means we’re about done.”

The spill occurred early Wednesday when three trucks crashed on the southbound Golden State Freeway at the Antelope Valley Freeway. More than 3,000 gallons of oil splashed from one tanker and flowed into a drain pipe that eventually led, through creeks and drainage systems, to the Los Angeles River.

On Thursday, 36 hours later, the spill had reached the Arroyo Seco, north of Downtown Los Angeles, officials said. But the oil had thinned out to merely a sheen on the river’s surface, and cleanup crews predicted they would end their efforts sometime today.

The layout and concrete lining of the Los Angeles River facilitated the flow of oil more than 25 miles from the northern border of the San Fernando Valley to near Downtown, Caywood said. “This has been designed as a storm channel,” he said. “It speeds the oil on its way.”

The oil also fouled at least 10 birds in the Van Norman Dam area, and due to Wednesday’s inclement weather, Fish and Game agents were unable to rescue the animals.

“Just a little bit of oil can be fatal” for birds, said Alexia Retallack, a spokeswoman for the Fish and Game Department’s Office of Oil Spill Prevention and Response.

Oil coats birds’ feathers, ruining their insulation and exposing them to the water’s chill, she said. Birds may also try to preen the oil from their feathers and die of poisoning.

Most birds fly away when smeared with oil, Retallack said, making it even tougher to track them down in an area near the dam that was still slippery from Wednesday’s showers.

The search for the smeared birds is scheduled to continue for a week, but officials said no more birds were found Thursday.

Also Thursday afternoon, CHP officers opened up The Old Road between Sierra Highway and Calgrove Boulevard, which had been closed after oil from the crash spilled onto it from the freeway.

Caywood said the Los Angeles River is often polluted by oil released by traffic collisions.