Common Guillemot

Extinct as a breeder

The most emblematic bird of the Berlengas and the symbol of its Nature Reserve, where Portuguese colonies once marked the species' southern breeding limit. Its numbers collapsed from about 6,000 pairs on Berlenga in 1939 to 320 adults in 1977, 70 in 1981, a last confirmed nest in 2002, and a single bird in June 2012, it is likely now extinct as a Portuguese breeder. It nests on inaccessible cliff ledges, laying a single egg, and dives tens of metres for small fish; drowning in synthetic gillnets drove the collapse, alongside overfishing and oil pollution. Today it is an uncommon winter visitor.