Abstract

We report two recently collected specimens of Accipiter imitator from Isabel Island, one of them the first specimen of a melanistic individual of the species. Surprisingly, we found no specimen records from Isabel of Accipiter albogularis, a very similar congener that occurs together with A. imitator on several islands. We call attention to the difficulties of sight identification and, based on a study of specimens, describe and tabulate morphological differences between the two species. We also give skeletal measurements of several species of Accipiter.