Sympatric distribution of Magellanic and Humboldt Penguins in southern Chile: ecological implications of coexistence and hybridization

Hiriart-Bertrand L. & A. Simeone 2010. 7 International Penguin Conference (Oral).

The importance of mixed colonies of Spheniscus penguins in southern Chile has received little attention although first mixed colonies were reported in the mid 80s. The sympatric distribution of Humboldt (Spheniscus humboldti) and Magellanic penguins (S. magellanicus) along the Chilean coast its still confuse and only few colonies containing both species have been reported in the last years. Information about these colonies is mostly restricted to population numbers and threats. During fieldwork at Puñihuil (42ºS) in the 2008-2009 breeding season we reported for the first time the occurrence of mixed (i.e. Humboldt-Magellanic) breeding pairs and phenotypic hybrids showing intermediate characters of both nominate species. These records show an important breeding interaction between both species, but we still ignore the proportion of hybrids and heterospecific pairs among the population in the region. We discuss the relevance of hybridization and coexistence and their potential consequences in speciation and possible mechanisms of adaptation both at land (breeding sites) and at sea (feeding areas).