The distribution, specimens and status of Chestnut Owlet Glaucidium (capense) castaneum and Albertine Owlet G. (c.) albertinum

Abstract

Chestnut Owlet Glaucidium (capense) castaneum and Albertine Owlet G. (c.) albertinum are poorly known members of the African Barred Owlet Glaucidium capense complex, confined to the Albertine Rift of East Africa. Recent taxonomic treatments have seen them variously considered as subspecies of capense, as separate monotypic species or, in the case of castaneum, a polytypic species. A paucity of museum material and field knowledge of each, combined with oversight and misinterpretation of some primary literature, has contributed to this uncertainty. This study reassesses their status and corrects numerous errors, misunderstandings and contradictions concerning specimen material, distribution, morphology and voice. Only four specimens of castaneum are known, there are no documented observations of the bird in life and no acoustic recordings. There are seven specimens of albertinum in collections. No field sightings have ever been documented but several recordings attributed to albertinum exist. Despite its close similarity to the voice of capense, there is no published evidence that albertinum reacts to playback, unlike the remaining taxa of the complex. I conclude that castaneum is a modestly distinct subspecies of capense. In contrast, albertinum, which differs conspicuously from the others in the complex by its disproportionately short tail, and which may be parapatric with castaneum, merits treatment as a species.