Diet and Roost Site Characteristics of the Christmas Island Hawk-Owl Ninox natalis

Abstract

In a two year study, Christmas Island Hawk-Owls Ninox natalis chose to roost in the bottom third of the canopy of trees with particularly deep crowns, in areas with fewer low understorey and more mid-level understorey trees, suggesting a preference for sheltered, concealed, roost sites with easy escape routes below them. Analysis of regur-gitated pellets, stomach samples and faeces showed the owls to be primarily insectivorous, eating a wide variety of medium to large insects, especially Orthoptera, Lepidoptera and Coleoptera. They supplemented this diet with vertebrates of which introduced Black Rats Rattus rattus were the most important in this study. Other studies have found native and introduced geckos as well as the Christmas Island White-eye Zosterops natalis in their diet. Owls snatched their prey from the understorey, hawked insects around streetlights, ‘long-stay perch hunted’ along roadsides and presumably also fed in and above the canopy.