The current status of the threatened Christmas Island Hawk-Owl Ninox natalis

Abstract

Much ambiguity has surrounded the total population size of the threatened Christmas Island Hawk-Owl Ninox natalis, with population estimates ranging anywhere from 10 pairs to 1000 mature individuals. Call-playback surveys were carried out in August and September 2011 along Christmas Island’s extensive road network in an attempt to gain insight into the Hawk-Owl’s present population size. A total of 10 Hawk-Owls was observed, and a further 22 were heard during our investigation. Hawk-Owls were unevenly distributed throughout the island, with notable concentrations clustered around areas of human settlement on the island’s north-western and north-eastern coastline. Our findings suggest that recent estimates of 1000 mature individuals may be a significant overestimate. Further research is urgently needed to determine if this tiny population is presently in decline and if active management should be implemented to ensure the long-term survival of this endemic owl.