Introduction

The swallow-tailed gull is a common resident of the Galapagos archipelago, especially in the easternmost islands.  There is an estimated population of 10,000 - 15,000 pairs in over 50 colonies.  They are endemic to the Galapagos with the exception of a small colony on Malpelo Island off the west Columbian coast.

Identification

Swallow-tailed gulls are distinctive in appearance and are the only common whitish gull with an unmistakable forked tail.  Adults have grey necks and upper parts, while their under parts are white.  Breeding adults have dark grey plumage and head, large eyes with red eye-rings and a black bill with a pale base and tip.  Meanwhile, non-breeding adults have white heads and dark eye-patches.  During flight, a distinctive triangular pattern of grey back and wing coverts, white secondaries and black primaries can be seen.

Voice

The swallow tailed-gull has a range of calls, which possibly have a function in echolocation.  Their most frequently used alarm call is a rattle, interspersed with a high-pitched "pee" sound.

Behaviour

Swallow-tailed gulls do most of their feeding during the night, which usually takes place several miles from land.  Their flight pattern is buoyant and not dissimilar to that of the tern.

Photograph kindly provided by Anele Waters