Status of Black Oystercatchers in Prince William Sound, Alaska, Nine Years After the Exxon Valdez Oil Spill

We studied breeding Black Oystercatchers (Haematopus bachmani) in Prince William Sound, Alaska in 1998 to assess whether these birds have recovered from previously identified effects of the 1989 Exxon Valdez oil spill. We collected data on nesting distribution, nesting effort and success, and chick development and survival. We compared among-year differences in distribution and abundance of breeding pairs using data collected by other investigators from 1989-1993 and conducted within-year comparisons that contrasted previously oiled and unoiled sites at two scales: regional and territorial. We found no oiling effects for nesting effort, breeding phenology, egg volumes, chick growth rates, and chick survival. Only nesting success showed an apparent oiling effect at the regional scale. Nest predation appeared to be the dominant force influencing nesting success in 1998, but regional differences in predation rates probably were unrelated to the oil spill. We concluded that oiling from the Exxon Valdez oil spill did not negatively affect breeding oystercatchers in 1998 and that this population largely has recovered from the effects of the spill.