Swallow-tailed gulls (Larus furcatus) at nest site.
Española (Hood) Island
ECUADOR. South America
ENDEMIC TO GALAPAGOS
The world's only nocturnal and oceanic gull. At dusk it flies out to sea to feed. They rely on the bioluminescent light given off by squid - their favourite food - to find them. They breed either on the sand or on cliff edges. To prevent themselves crashing into the cliff walls on their return in darkness, they utter clicking vocalisations, thought to be a form of primitive echo-location, similar to that of bats. They have a less than annual breeding cycle so chicks can be seen at any time of year.