The breeding distribution and status of Abbott's booby (Sulidae: Papasula abbotti) on Christmas Island, Indian Ocean

Abstract

The breeding distribution and population status of the endangered seabird Abbott's booby (Sulidae: Papasula abbotti (Ridgway) Olson & Warheit, 1988) were assessed by an island-wide survey on Christmas Island (Indian Ocean) in 1991. The species is now endemic to the island. A total of 1833 breeding sites were located, and it is estimated that the total breeding population is around 2500 pairs, 600 pairs more than the most recent estimate of 1900 pairs in 1983. We do not interpret the difference as a genuine increase in the breeding population — instead, we attribute it to the discovery of areas on the island where Abbott's boobies have probably always nested, but have never been recorded. Although this result has alleviated immediate concern for the future of P. abbotti, fields cleared for phosphate mining prior to 1987 still pose a continuing threat to the species — 36% of the population still nest near enough to clearings to be adversely affected by them. The Australian Nature Conservation Agency is currently rehabilitating mined fields to reduce their impact on the breeding population, and to eventually create a new breeding habitat for P. abbotti.