HABITAT USE BY SEYCHELLES SOOTY TERNS STERNA-FUSCATA AND IMPLICATIONSFOR COLONY MANAGEMENT

The relationship between sooty tern Sterna fuscata nest densities and vegetation characteristics of the breeding colonies was investigated o n four islands in the Seychelles. Nest densities were greatest in area s with a vegetation caller of 30-50%, and areas that provided these co nditions were generally dominated by pourpier Portulaca oleracea. On A ride Island sooty terns nested at low density under an enclosed tree c anopy but on the other islands nests were generally in the open, among sparse vegetation. On Desnoeufs Island, where eggs are harvested comm ercially for human consumption, sooty terns avoided nesting in dense a reas of epi bleu Stachytarpheta jamaicensis, an introduced plant whose success on the island may be related to egg exploitation. Management of colony vegetation, especially the control of introduced aggressive species, and the encouragement of optimum conditions for nesting, coul d increase the numbers of nesting sooty terns and their reproductive o utput, helping to buffer them against adverse effects of human activit y. Appropriate protection of sooty tern colonies can also benefit rare r and more vulnerable seabirds and turtles that share nesting islands. (C) 1997 Elsevier Science Ltd.