A brief response to Wiens et al., twelve years after the Exxon Valdez oil spill

We briefly address the four main issues that Wiens et al. (2001) present in their commentary on Irons et al. (2000). In summary our response is: (1) We discussed before-after control-impact design assumption, at length in our paper. Data do not exist to resolve this issue and Wiens et al. fail to shed new light on it. (2) Contrary to Wiens et al.'s assertion, we discussed only statistically significant results. (3) Wiens et al. disagreed with our interpretations of a few select results. We stand by our interpretations. (4) Wiens et al. believe that the evidence we presented from other studies showing that Exxon Valdez oil still exists in Prince William Sound (PWS), and that birds are still ingesting it, is equivocal in demonstrating cause and effect. We agree, but arguments to the contrary are equally equivocal. Data from continued monitoring of marine birds in PWS support the conclusion that as of July 2000 one taxon is recovering from effects of the Exxon Valdez oil spill and eight taxa are not.