Scientific investigation indicates shortages of preferred prey items, like anchovies and sardines, and rough winter weather as primary causes for the pelican mass-stranding. Scientists from the California Department of Fish and Game (DFG), the U.S. Geological Survey National Wildlife Health Center, Sea World San Diego and International Bird Rescue Research Center pooled their resources to determine why so many brown pelicans are stranding along the California and Oregon coast.

"Working collaboratively with other organizations, we have been able to quickly examine multiple causes for the stranding event," said DFG Wildlife Veterinarian Melissa Miller, in Santa Cruz. "Unfortunately, we are looking primarily at a cyclical event driven largely by weather and oceanographic conditions. Food shortage coupled with bad weather have taken a toll on the pelicans."

Mass-stranding of brown pelicans was reported along the California and Oregon coast about this time in 2009, again with widespread food shortages identified as a factor. Some stranded birds have little or no body fat stores and atypical foods in their digestive tracts. Shortages of preferred prey items could be caused in part by the current El Nino event.

Some pelicans have also had waterproofing problems with their feathers, possibly related to storm runoff from recent heavy coastal rains. Preliminary findings from postmortem examinations suggest that infectious disease and/or marine toxins are not major contributors to this event.

Live-stranded birds are responding quickly to feeding at rehabilitation facilities, although these facilities have been overwhelmed at the sheer magnitude of birds stranding along the coast. DFG is donating frozen trout to these organizations to assist with the rehabilitation effort.

When pelicans are starving and sick they may fly into or be found in unusual places, be unaware of their surroundings, tolerate human approach or demonstrate other unusual behaviors. Anyone finding stranded or dead pelicans should not approach or handle the birds, but note their location and report it to either 800-39-WHALE in Los Angeles County or 866-WILD-911 elsewhere.