Bald eagle population in Prince William Sound after the Exxon Valdez oil spill

We initiated studies to determine whether the Exxon Valdez oil spill influenced bald eagle (Haliacetus leucoephalus) demography in Prince William Sound (PWS), Alaska. Using fixed-wing aircraft, we surveyed bald eagle populations within random plots once each year and censused nearly all islands in PWS in 1989-91 and 1995 to estimate population size. We calculated population indices (uncorrected for birds not seen) of 2,199; 1,935; 2,116; and 2,641 adult eagles for the 4 years studies. Subsequent to the 1989 oil spill, the eagle population returned to its estimated pre-spill size by 1995. The PWS bald eagle population has increased at an average annual rate of 3.7% from 1982 to 1995. The proportion of immatures in the population averaged 29% and did not vary significantly among years.