Sooty Tern

Overview

The Sooty Tern is a highly pelagic tropical seabird that, remarkably, may remain continuously airborne over open ocean for extended periods outside the breeding season, rarely if ever alighting on the water's surface. Its strongly contrasting plumage, blackish-brown above and crisp white below, combined with a bold white patch on the forehead, sets it apart from the generally paler gray-backed terns of temperate regions. The tail is long and deeply forked, aiding sustained flight over vast stretches of open ocean.

Breeding occurs in enormous colonies on remote tropical and subtropical islands, some hosting hundreds of thousands of pairs, after which adults and young disperse widely over open ocean, sometimes for years at a stretch before returning to breed.

Feather Identification

• Wing and back feathers: Uniformly blackish-brown to sooty black across the upperwing, back, and crown, a notably darker tone than the pale gray upperparts of most temperate terns.
• Body feathers: Crisp white underparts and a bold white patch on the forehead, contrasting sharply with the dark upperparts and cap.
• Tail feathers: Long and deeply forked, an adaptation suited to prolonged, sustained flight over open ocean.
• Compared to similar species: Bridled Tern is similar but shows browner (less black) upperparts, a white collar around the hindneck, and a white forehead patch that extends further back past the eye; Sooty Tern's upperparts are darker and more uniformly blackish, and its white forehead patch is more restricted.

Plumage Details

Adults show blackish-brown upperparts, a black cap, a white forehead patch that does not extend noticeably past the eye, and clean white underparts, with little seasonal variation. Juveniles are entirely dark sooty brown with pale, scaly-looking spotting on the back and wing coverts, lacking the crisp white underparts of adults, and gradually molt toward the adult pattern over a period of a few years spent almost entirely at sea before returning to land to breed.

Habitat & Range

Sooty Terns breed in massive colonies on remote tropical and subtropical islands across the Atlantic, Pacific, and Indian Oceans, nesting on open ground often in extremely dense aggregations. Outside the breeding season the species is intensely pelagic, ranging over vast expanses of open tropical and subtropical ocean far from any land, with immature birds in particular remaining at sea for extended periods, sometimes several years, before first returning to a colony.

Behavior & Field Notes

Sooty Terns forage by picking small fish and squid from the ocean surface in flight, often in association with predatory fish schools that drive prey toward the surface, and are notable for rarely landing on the water, resting on the wing for extended periods instead. They breed in enormous, densely packed colonies, some of the largest seabird colonies in the world, with constant activity and calling giving rise to the colloquial name "wideawake tern" in some regions due to the incessant noise. The call is a distinctive, sharp "wide-awake" or "ker-wacky-wack" note repeated frequently at colonies. Its dark upperparts, crisp white underparts, and highly pelagic habits distinguish it from nearly all other terns encountered near shore.