Vocal divergence and new species in the Philippine Hawk Owl Ninox philippensis complex

We show, based on morphology and especially vocalisations, that the Philippine Hawk Owl Ninox philippensis requires treatment as seven allopatric species and at least one additional subspecies. Morphological distinctions between three groups of taxa are striking, and although taxa within one major group are relatively similar in plumage they vary rather consistently in size and proportions. It has not been possible until now to resolve the species limits in this complex due mainly to the lack of sound recordings of key taxa, a problem now rectified. Vocalisations differ significantly between all seven species, the limits of which are incongruent with all previous taxonomies. Taxa from Mindoro ( mindorensis ), Mindanao ( spilocephala ), Camiguin Sur (named herein), and the Sulu Islands ( reyi ) exhibit especially great vocal differences from all other taxa along with smaller but consistent differences in plumage and morphometrics. Although specimens have been in museum collections for many years, two of these species and one subspecies have heretofore remained undescribed, and we formally name these taxa for science. The recommended species-level treatment and English names of the N. philippensis complex are: Luzon Hawk Owl N. philippensis ; Mindanao Hawk Owl N. spilocephala ; Mindoro Hawk Owl N. mindorensis ; Sulu Hawk Owl Ninox reyi ; Romblon Hawk Owl N. spilonota ; Camiguin Hawk Owl new species; and Cebu Hawk Owl new species.

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