Two birds oiled after an undersea pipeline ruptured off the Southern California coast have been treated and released.

Workers brought the ruddy duck and eared grebe Wednesday to a shorefront park in a harbor area of Huntington Beach. The duck swam away and the grebe, a small waterbird, took flight.

“It’s a joyous occasion,” said Michael Ziccardi, director of the Oiled Wildlife Care Network.

Officials have reported 28 oiled birds since the spill a little more than a week ago off the coast of Orange County. Forty five birds have been found dead, though not all were visibly oiled, he said.

Birds are often the first wildlife affected by an offshore spill because oil clumps their feathers and leaves them exposed to cold water temperatures. Experts have said relatively few birds seem to have been hit by this spill, possibly because migratory birds are not typically present at this time of year.

The spill was confirmed on Oct. 2, a day after residents reported a petroleum smell in the area. Coast Guard officials said a pipeline that shuttles crude from offshore platforms to the coast leaked at least about 25,000 gallons (95,000 liters) and no more than 132,000 gallons (500,000 liters) of crude oil into the ocean. 

Officials have said the cause remains under investigation, and they believe the pipeline owned by Houston-based Amplify Energy was likely damaged by a ship’s anchor several months to a year before it ruptured.

Associated Press