Staff and volunteers work to clean oil off a brown pelican at the International Bird Rescue center in San Pedro, Los Angeles, California, United States, May 22, 2015. [Photo/Agencies]

LOS ANGELES - More than two dozen marine mammals and nearly 40 birds, most of them pelicans, have been collected dead and alive from along California's oil-fouled coastline near Santa Barbara in the week since a petroleum pipeline ruptured there, wildlife officials said on Tuesday.

Of 38 oil-coated birds documented so far, 13 turned up dead and 25 were picked up alive, though two of the rescued birds have since died, said Dr. Michael Ziccardi, a veterinarian from the University of California, Davis, who heads the Oiled Wildlife Care Network.

The surviving birds, primarily brown pelicans, were all being taken to a wildlife care facility in Los Angeles to be cleaned up, nursed back to health and hopefully released again to the wild.

Among marine mammals counted as apparent oil spill victims, 12 California sea lions and six northern elephant seals were recovered alive, but two of the captured sea lions later died. Five more sea lions were found dead, along with carcasses of three common dolphins, Ziccardi said.

The same tallies of marine mammal and bird casualties were reported by Mary Fricke, a spokeswoman for the California Department of Fish and Wildlife.

Post-mortem exams must be conducted on all the dead animals to confirm whether they actually perished from petroleum exposure, officials said. Results from the first dolphin exam were inconclusive as no visible signs of oil contamination were found externally or internally, Ziccardi said.

The full extent of damage to wildlife remains unknown since last Tuesday's pipeline rupture dumped as much as 2,400 barrels (101,000 gallons or 382,327 liters) of crude oil onto the shoreline and into the ocean west of Santa Barbara.