The distribution and population of the Seychelles (Bare-legged) Scops Owl Otus insularis on Mahe: consequences for conservation (vol 146, pg 27, 2004)

This study details the first baseline survey of the Critically Endangered Seychelles Scops Owl Otus insularis, currently only recorded from the 152-km(2) island of Mahe, the largest and highest island in the granitic Seychelles, western Indian Ocean. A survey was conducted in October 2000-March 2001 using playback of conspecific calls in random squares (500 m x 500 m) with midpoints being at least equal to 100 m asl. Playback was conducted in 159 of a possible 375 squares (42%). Territorial responses were detected in 60 of 159 (38%) squares, which represented an estimated 70 distinct territorial responses. Pairs responded in 51% and single birds responded in 49% of squares where a response was elicited. Scops Owls were more likely to be detected at higher altitudes, in mixed forest, and sympatrically with endemic frogs (Tachycnemis seychellensis and Sooglossus spp.). Two models were used to predict population: one based exclusively on altitude resulted in a population estimate of 134-159 territories (268-318 individuals) within a 34-km(2) range, whereas a second incorporating altitude and vegetation, which excluded unsuitable habitat, resulted in an estimate of 125-142 territories (250-284 individuals) in a 31-km(2) range. We discuss the implications of our findings to the Owl's conservation status and management.