Sooty Shearwater

The Sooty Shearwater is a medium-sized shearwater with almost uniformly dark sooty-brown plumage overall, relieved mainly by silvery-white underwing linings that flash conspicuously as the bird banks and glides in flight.

This species is renowned for its extraordinary annual migration: birds breeding on islands off New Zealand, Chile, and other Southern Hemisphere sites travel enormous distances northward each year, tracing a huge, roughly figure-eight-shaped loop across the Pacific or Atlantic Ocean in search of the best feeding conditions in each hemisphere's summer.

Sooty Shearwaters often gather in enormous, dense flocks at sea, sometimes numbering in the tens or hundreds of thousands, particularly where productive currents concentrate their prey near the surface.

Key field marks

• Uniformly dark sooty-brown plumage overall
• Silvery-white underwing linings, visible as flashes in flight
• Slender, dark bill and a fast, powerful flight with stiff wingbeats

Similar species

• Short-tailed Shearwater is very similar and best distinguished by a shorter bill, a more rounded head profile, and subtler underwing pattern, requiring close observation.
• Sooty Albatross species are much larger with a longer, more slender wing shape and a different flight style, and occur only in the Southern Hemisphere.

Sooty Shearwaters breed in large colonies on islands off New Zealand, southern Chile, and other Southern Hemisphere locations, nesting in burrows on grassy or forested slopes. After breeding, they undertake transequatorial migrations, ranging widely across the Pacific and Atlantic Oceans.

During the non-breeding season, large numbers occur in productive Northern Hemisphere waters, including off the coasts of North America and Japan, before the birds return south to their breeding islands.

Voice

At breeding colonies, Sooty Shearwaters give loud, wailing, and cackling calls at night around their nesting burrows, but are generally silent while foraging at sea.

Feeding

They feed on small fish, squid, and krill, pursuing prey underwater with wing-propelled diving, sometimes reaching considerable depths, and often forming large feeding flocks with other seabirds and marine mammals.

Nesting and breeding

Pairs nest in burrows dug into soft soil on breeding islands, visiting the colony mainly at night. A single egg is laid, and both parents share incubation duties before departing on their long migratory journey.