Abstract

We describe the first nesting colony of the Red-billed Tropicbird (Phaethon aethereus) known in Chile, the southernmost colony for this species described to date. During two breeding seasons the nesting phenology was observed. The birds arrived in October, remaining until the end of March or early April when the fledglings left their nests. The birds nested successfully during both seasons. It is unknown when the colony was first established, but we suggest that the colonization was a result of the displacement of these birds from islands in Peru or Ecuador due to the El Nino-Southern Oscillation (ENSO) event of 1982-1983.