Use of oil-affected habitats by birds after the Exxon Valdez oil spill

This study investigated the effects of the Exxon Valdez oil spill o the use of oil-affected habitats by birds during 1989--1991. The authors measured densities of birds in bays that had been subjected to various levels of oiling from the spill during survey cruises that were conducted throughout the year in Prince William Sound (PWS) and during summer along the Kenai Peninsula. Overall, 23 of 42 (55%) species in PWS and 22 of 34 (65%) species on the Kenai showed no evidence of oiling impacts on their use of habitats. Most species that did not show initial negative impacts had recovered by late summer 1991 when the study concluded, although 6 of the 19 species initially impacted in PWS and 6 of the 12 species initially impacted along the Kenai did not exhibit clear signs of recovery by this time. A Principal Components Analysis of species examined from PWS revealed extensive overlap in ecological attributes among species that were and were not negatively impacted in their use of oil-affected habitats. Species that did not show clear evidence of recovery tended to be intertidal feeders and residents of PWS, but other ecologically similar species evidenced either no initial impacts or rapid recovery. These similarities suggest that the prognosis is good for the species for which they were unable to document recovery in habitat use. These findings, together with the rapid rates of recovery in habitat features reported in other studies, suggest that impacts of the Exxon Valdez oil spill on avian use of oil-affected habitats generally were not persistent. 48 refs., 10 figs., 6 tabs