Sooty tern

Lore & Background

The sooty tern was first described by Carl Linnaeus in 1766 as Sterna fuscata. It was later moved to the genus Onychoprion, whose name derives from ancient Greek onux ('claw' or 'nail') and prion ('saw'); the species name fuscatus is Latin for 'dark'. The species shows little interspecific variation but is usually divided into six to eight allopatric subspecies, with six accepted by the IOC. The affinities of eastern Pacific birds, including O. f. manutarus of Easter Island, are most strongly contested.

Sooty terns breed in colonies on rocky or coral islands, nesting in a ground scrape or hole and laying a single egg, typically in the afternoon. They feed by picking fish from the surface in marine environments, often in large flocks, and rarely come to land except to breed. Due to the lack of oil in their feathers, they cannot float and spend their entire time on the wing, staying out to sea for 3 to 10 years.

This bird is migratory and dispersive, wintering more widely through the tropical oceans. It is generally found inland only after severe storms. It is a rare vagrant to western Europe, and hurricanes can devastate small breeding colonies. An exceptionally common bird, the sooty tern is not considered threatened by the IUCN.

Reader's Guide

The sooty tern is a significant species in tropical marine ecosystems, known for its extreme pelagic lifestyle and ability to remain airborne for years. Its breeding colonies on remote islands are vulnerable to storms, but the species remains abundant globally. The bird has cultural importance in Polynesia, where it is often called manutara, and on Easter Island, where it played a central role in the tangata manu ('birdman') ritual: the hopu (champion) who retrieved the first manutara egg from Motu Nui islet became that year's tangata manu, securing prime access to resources. The sooty tern's call, a loud 'wide-a-wake', has given it colloquial names such as 'wideawake tern' and the Hawaiian ʻewa ʻewa, meaning 'cacophony'. Its taxonomy remains subject to debate, particularly regarding eastern Pacific populations, reflecting ongoing ornithological research.

Did You Know?

• The sooty tern can stay out at sea for 3 to 10 years without coming to land.
• Its call is a loud piercing 'wide-a-wake', also cited as ker-wack-a-wack.
• The species was described by Carl Linnaeus in 1766 as Sterna fuscata.
• On Easter Island, the sooty tern and spectacled tern are collectively known as manutara and were central to the tangata manu ritual.