Imminent extinction of the guanay cormorant on the Atlantic South American coast: a conservation concern?

Abstract

Guanay cormorants Phalacrocorax bougainvilli aredistributed mostly on the Pacific coast of Peru and northern Chile. A smallpopulation of around 50 pairs was described on the Patagonian Atlantic coast inthe late 1960s. Further records have revealed a progressive decrease of thispopulation. During 1999 we looked for guanay cormorants at those Atlanticcolonies where the species was recorded in the past. Only four individuals weredetected in one colony (Punta Lobería), and all of them were mated withking cormorants P. albiventer. In addition, we recordedhybrids between guanay and king cormorants mated with pure king and imperialcormorants P. atriceps. Causes of the population declineare unknown. Since guanay cormorants inhabiting the Atlantic coast could be agenetically differentiated population, we emphasize the need for molecularstudies. If genetic polymorphism is detected, the capture of remnant individualsin order to constitute a genetic stock should be considered.