Brown Pelican Pacific , Photo: ©Alan Wilson

The California Department of Fish and Game (CDFG) is reporting that the primary causes of the recent Brown Pelican mass stranding (involving varying degrees of incapacitation of hundreds of birds) along the Oregon and California Coast are related to shortages of preferred prey items, such as anchovies and sardines, and rough winter weather likely related to the current El Niño event.

CDFG, the U.S. Geological Survey National Wildlife Health Center, Sea World San Diego and the International Bird Rescue Research Center (IBRRC) pooled their efforts to determine the causes for the bird deaths and strandings, and ruled out infectious disease and marine toxins as major contributory factors. Some pelicans have had waterproofing problems with their feathers, possibly related to storm runoff from recent heavy coastal rains.

More than 300 birds are being rehabilitated at the IBRRC facilities in San Pedro and Cordelia, California. CDFG has been donating frozen trout to organizations conducting the rescue feeding. Rehabilitation has been taking one to two weeks and rescued birds are said to be responding well to treatment. Birds first became stranded around the middle of January but the numbers being recovered each day have greatly diminished in recent days.

“When you allow overfishing of any seabird's prey base and then compound that with impacts from El Nino events, which may become stronger or more common with climate change, you are spelling disaster for the bird. Their prey bases have got to be better protected if they are to survive long term,” said Dr. Jessica Hardesty Norris, American Bird Conservancy Seabird Program Director.