Preliminary results of the California Department of Fish and Game's (DFG) investigation into central coast California brown pelican deaths indicate causes may be starvation and malnutrition. The large number of recently fledged birds competing with adults for the existing food supply might be the reason for unusually high mortality rates.

?Į?ĮDFG veterinary pathologists from the Marine Wildlife Care and Research Center have been investigating the mystery since early May, when the endangered birds first started stranding in the Ventura area. They will continue to examine affected pelicans and issue a report once significant findings and summary information have been collected.

?Į?ĮSeveral dozen adult and immature pelicans, either very sick or dead were found on Ventura County beaches in May. Initially, the birds' symptoms suggested possible domoic acid intoxication, but laboratory test results have so far been inconclusive. By June 1, investigators had found as many as 100 more pelicans with similar symptoms, first in the Pismo Beach and Morro Bay areas, and then in the Monterey Bay area. These pelicans were almost exclusively juveniles in poor body condition. In the last few days, investigators sent 31 dead pelicans to DFG's wildlife care and research center in Santa Cruz, where biologists and veterinary pathologists are examining them. Starvation and malnutrition are the most common findings, but one bird had a broken wing and one was heavily oiled.

?Į?ĮCalifornia brown pelicans breed and lay their eggs in winter, with the majority nesting in Mexico and smaller numbers on California's Channel Islands. The eggs hatch in early spring and chicks usually begin to fledge in May and June. Nesting was very successful this year, with the first breeding on Prince Island in recent history.

?Į?ĮBoth state and federal agencies have listed the brown pelican as an endangered species since the 1970s, due to severe reproductive failure caused by DDT pollution. Recovery efforts over the last three decades have resulted in the seabird again becoming a common sight along the West Coast. In light of the rebound success, the U.S. Fish and Wildlife Service is considering delisting the species in the near future.

?ĮThe DFG has been working with the UC Davis Wildlife Health Center and the International Bird Rescue Research Center throughout this investigation.