Manx Shearwater

The Manx Shearwater is a slim, medium-small shearwater with crisply contrasting plumage: black upperparts and a clean white underside, sharply demarcated along the flanks, giving the bird a distinctive black-and-white flashing appearance as it banks in flight.

At sea, this species has a characteristic low, fast, gliding flight, alternating stiff wingbeats with long glides that bring it so close to the water's surface that it appears to shear the wave tops, the origin of the family name "shearwater."

Some of the world's largest colonies of Manx Shearwater are found on grassy offshore islands in the United Kingdom and Ireland, such as Skomer and Rum, where birds nest in burrows and visit the colony only under cover of darkness to avoid predatory gulls and skuas.

Key field marks

• Sharp black-and-white contrast between dark upperparts and white underparts
• Slim build with narrow, stiffly held wings
• Fast, low, banking flight close to the wave surface

Similar species

• Balearic Shearwater, a close relative, is browner overall with less crisp contrast between upper- and underparts, and breeds in the Mediterranean rather than the North Atlantic.
• Sooty Shearwater is much larger and uniformly dark brown, lacking the Manx Shearwater's clean white underside.

Manx Shearwaters breed on offshore islands across the North Atlantic, with major strongholds in the United Kingdom and Ireland, including islands like Skomer, Skokholm, and Rum, where deep, soft soil allows extensive burrow digging. Colonies are also found in Iceland and the Faroe Islands.

Outside the breeding season, the species migrates across the Atlantic to winter in productive waters off the coast of South America, particularly off Brazil and Argentina, before returning to the Northern Hemisphere to breed.

Voice

At night around breeding colonies, Manx Shearwaters give eerie, cackling, and crowing calls exchanged between mates and rivals, audible from within burrows and overhead in the dark.

Feeding

They feed on small fish such as sprat and herring, along with squid and crustaceans, caught by surface-seizing and shallow pursuit diving, sometimes at considerable depths for a bird of its size.

Nesting and breeding

Pairs nest in burrows dug into soft, grassy soil, returning to the same burrow in successive years, and lay a single egg. Adults visit the colony only at night, and fledglings depart the burrow alone, finding their own way out to sea.