The Manx Shearwater is a widespread migratory seabird of the Atlantic Ocean. Famous for their impressive lifespan and homing abilities, some individuals will travel a million kilometers or more in their lifetime.
The Manx Shearwater is a medium-sized black and white seabird with very long, narrow wings. They have a thin black bill with a hooked tip and large webbed feet for swimming. They are completely black above and pure white below, with black edges around the underside of their pointed wings.
Manx Shearwaters are most often seen in flight when their lengthy wings and low, stiff-winged flight interspersed with gliding are helpful for identification. The sexes look alike throughout the year, although females are slightly smaller on average. Juveniles have similar plumage to adults.
These birds can be confused with a few similar species, including the Audubon, Balearic, and Great Shearwaters.
Manx Shearwater swimming on a canal
Manx Shearwaters have a body length of 12 to 15 inches or 30 to 38 centimeters.
They weigh about 14 ounces or 400 grams on average, although their mass varies between 12 and 20 ounces (350 - 575 g).
Manx Shearwaters have an impressive wingspan of 30 to 35 inches or 76 to 89 centimeters.
Manx Shearwater flying over the sea
Manx Shearwaters produce various wailing, crowing, and cooing calls on dark nights, either from their nest burrows or while flying above the colony. They are usually silent in the non-breeding season.
Manx Shearwaters eat fish, squid, and crustaceans, which they catch on the surface or by swimming underwater. Small schooling fish (about 6 in/15 cm long) like herring, pilchards, and sprats are their regular prey.
Manx Shearwater chicks eat regurgitated fish provided by both parents. Adults travel long distances to forage, and these partially digested meals may be sourced over 200 miles away from the nest.
Young Manx Shearwater chick
Manx Shearwaters are marine birds that hunt over the open ocean, typically within the shallow waters of the continental shelf when breeding and overwintering but also over deep pelagic areas during migration. They nest on islands and coastal headlands, usually in low-vegetated or grassy habitats with suitable soils for burrowing.
Manx Shearwaters are widespread on both sides of the Atlantic Ocean. They occur from Greenland in the north to the coastlines of South Africa and Argentina in the south.
Adults breed at scattered localities in the Northern Hemisphere around the coasts of the United Kingdom, France, Iceland, and the Faeroe Islands, and south to the Canary and Azores Islands. Smaller numbers breed off Newfoundland and occasionally further south in the United States.
Manx Shearwaters spend most of their lives out at sea. They are masters of the sea and the skies but downright clumsy on land, only coming ashore after dark to nest.
Manx Shearwaters are fairly common seabirds of the Atlantic, although their offshore foraging and nocturnal nesting habits make them difficult to observe from land.
Manx Shearwaters occur widely off the east coast of the United States, from Maine to Florida, although they are rarely seen from the shore. They are most common in the Northeast from spring to fall.
Bardsey, Skokholm, and Skomer Islands off Wales, and Rum Island off the west coast of Scotland are the most important breeding sites for Manx Shearwaters in the United Kingdom.
They are difficult to spot on land since they only return to their nests at night, but large numbers gather offshore before dark. Birdwatchers may also spot migrating birds from high vantage points along the west coast in spring and summer, especially when onshore winds bring them closer to shore.
Manx Shearwater flying low over the sea
Manx Shearwaters are remarkably long-lived birds. Their estimated life expectancy varies between 15 and 29 years, although some individuals have lived for over 50 years in the wild.
Manx Shearwaters nest on remote islands with few predators because they are virtually defenseless on land. Their eggs and chicks are highly vulnerable to rats, and accidental introductions of these rodents have practically wiped out some colonies.
Adults are most vulnerable to other birds, so they avoid coming to shore until after sunset. The following species are known to predators:
Manx Shearwaters are protected by the Migratory Bird Treaty Act in the United States and the Wildlife and Countryside Act in the United Kingdom.
Manx Shearwaters are a ‘Least Concern’ species on the IUCN Red List, with an estimated population of 680,000 to 790,000 individuals.
Manx Shearwater in-flight out at sea
Manx Shearwaters nest underground in burrows they dig themselves, in old rabbit burrows, or under boulders. Both partners excavate by loosening the soil with their bills and shoveling it out with their feet. They may line the nest chamber with plant material or simply lay their eggs on bare soil.
Manx Shearwaters nest between April and October, with peak egg-laying in May and June. The eggs take 51 days to hatch on average, and both partners share incubation duties in shifts that last several days at a time. The chick fledges the nest after about 69 days and leaves the area of the colony.
Manx Shearwater eggs are large and dull white, measuring approximately 60 millimeters long and 41 millimeters across. They lay just one egg per year, and older females lay larger eggs than younger birds.
Manx Shearwaters are monogamous and form lasting pair bonds. These long-lived birds may mate for life, although some divorce after unsuccessful breeding attempts. Pairs will return to nest in the same burrow year after year.
Manx Shearwater resting on the grass
Manx Shearwaters are generally gregarious and peaceful, although they can be aggressive when claiming a nesting site.
Manx Shearwaters sleep out on the water while floating.
Manx Shearwaters are highly migratory seabirds that return to nest at the same site throughout their lives. Adults and fledglings begin to leave their breeding grounds in late summer and travel fast, covering hundreds of miles each day. They arrive at wintering grounds off the east coast of South America in October and stay until about February before beginning the return trip.
Manx Shearwaters out at sea
Manx Shearwaters are named after the Isle of Man, where they once bred in great numbers. They still nest there, although the original colony collapsed after a wrecked ship introduced rats to the island over two centuries ago.
The Manx Shearwater is not a Puffin, although its scientific name (Puffinus puffinus) certainly creates that impression! Shearwaters are from the Procellariidae family, while Puffins are from the Alcidae family.
Family:Petrels and shearwaters
30cm to 38cm
76cm to 89cm
350g to 575g
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