Chlidonias niger
The Black Tern is a small, graceful seabird that nests far from the ocean. These birds switch between radically different habitats in the breeding and non-breeding seasons, but habitat loss inland has caused their numbers to plummet since the mid-1900s.
Black Tern
Black Tern transitioning into breeding plumage
Black Tern, non-breeding plumage, in-flight
Juvenile Black Tern
The Black Tern is a slender, graceful species, slightly smaller than an American Robin but with very long, pointed wings and a slightly forked tail. In breeding plumage, they have all-black underparts and heads but gray wings, backs, and tails. Their bills, legs, and webbed feet are black.
These birds are buoyant and agile in flight. Their pale gray underwings and whitish rump contrast with the pure black head and body in flight, and the leading edges of their wings are silvery white.
They are much paler in non-breeding plumage, with whitish underparts and pale gray upperparts. Their most distinctive features are a black crown that extends down behind the eye and dark bars on either side of the breast.
Females Black Terns are similar to males but can be identified by their slightly paler breeding plumage. Juveniles are similar to adults in their pale non-breeding plumage but have brown back feathers with lighter edges. The forehead and base of the bill may be browner than on adults.
Black Tern, breeding plumage
Black Tern, non-breeding plumage
Black Terns are slender birds with a body length of 8⅔ to 11 inches or 22 to 28 centimeters.
Most adults weigh 1¾ to 2⅛ ounces or 50 to 60 grams, although some reach 3 ounces or 86 grams.
Despite their small body size, these birds have large wings with an impressive wingspan of 22½ to 26¾ inches or 57 to 68 centimeters.
Black Tern in-flight
Black Terns produce high-pitched squeaky ‘kik’ or ‘kip’ contact calls in flight. They make longer two or three-syllable calls during courtship and before returning to the nest. They also call frantically when a predator or person approaches their eggs or young.
Black Tern calling out
Black Terns are carnivores that prey on small fish, insects, and amphibians. They snatch food near the water’s surface or from the air but do not dive.
Black Tern chicks eat insects and small fish provided by their parents for up to five weeks. Both parents deliver food, bringing one meal at a time.
Black Terns in the marshes feeding
Black Terns inhabit shallow freshwater wetlands and marshes in the spring and summer but shift to marine environments in the winter. They are usually found within about 18 miles (30 km) of the coast, but some have been seen thousands of miles out to sea.
Black Terns occur in North and South America, Europe, Asia, and Africa. Their North American breeding range includes much of the northern half of the United States and the southern half of Canada. This population winters around Mexico, Central America, and South America to Peru. The Old World population occurs widely in Eastern Europe, Western and Central Asia. They overwinter along the west coast of Africa.
Black Terns are highly adaptable creatures that manage to survive in diverse habitats, from shallow ponds to the open ocean. They are primarily associated with water, although they spend much time flying and rarely land on the water.
Black Terns can be very common in suitable habitats, although they are sparsely distributed, and their species is in decline. The world population is estimated at 0.8 to 1.75 million individuals.
Black Tern perching on a fence rail
Black Terns are widespread breeding visitors to the northern half of the lower 48 states, particularly around the Great Lakes and Upper Mid-West. Look out for them flying over large, shallow marshes with emergent vegetation.
Black Terns are widespread but uncommon in the south of Canada, reaching the south of the Northwest Territories in summer. They are most numerous in the Canadian Prairie region of the west.
Hundreds of Black Terns migrate through the United Kingdom each spring and autumn. Although scarce, they could be seen over practically any freshwater habitat.
Black Tern getting ready to take-off
Black Terns can live for up to 17 years.
Black Tern eggs and chicks are vulnerable to many predators, including:
Black Terns are federally protected by the Migratory Bird Treaty Act of 1918 in the United States and the Migratory Birds Convention Act in Canada. Migrating birds in the United Kingdom are protected by the Wildlife and Countryside Act 1981.
Black Terns are not globally endangered, although they have suffered alarming declines and are listed as endangered locally in many US states, including New York, Wisconsin, and Pennsylvania.
Black Terns rely on extensive shallow wetlands for breeding and a variety of other freshwater habitats during migration. Habitat loss through wetland drainage and degradation are the major causes of their decline.
Black Tern, breeding plumage
Black Terns nest on extensive marshes with plenty of emergent vegetation like cattails and bulrushes. The nest is usually made on top of floating plant material, just a few inches above the water. The nest is made from similar materials arranged to form a shallow bowl. Floating plants may seem like a very risky place to nest, but the habitat reduces the threat of mammal predators like raccoons.
Black Terns nest in the spring and summer, usually producing a single brood each year. They lay their eggs in late May or June, and incubation lasts about three weeks (20 - 23 days). The chicks fledge about three weeks later.
Black Terns typically lay three speckled and blotched eggs with an olive to pale brownish background color. The eggs measure approximately 34 millimeters long and 24 millimeters wide.
These birds are monogamous during the nesting season. Pairs may reunite at the nest site in successive years, but most will find a new partner.
Black Tern sitting on the nest
Nest of a Black Tern with three eggs
Black Terns are rarely aggressive toward their own kind, although they are courageous in protecting their eggs and young from predators. They will divebomb and peck humans and predators that approach their nest.
Black Terns roost in colonies on mudflats and beaches when not breeding. On the nesting grounds, they may sleep on floating vegetation, fallen tree branches, or their nest. They perch on floating debris and seaweed out at sea.
Black Tern in-flight over natural habitat
Black Terns are highly migratory across their range. These birds migrate between equatorial and southern hemisphere coastal overwintering grounds and nesting areas on freshwater wetlands in the temperate zone of the Northern Hemisphere.
Black Terns are native breeding and overwintering birds in North America. The subspecies found in North and South America are known scientifically as Chlidonias niger surinamensis.
Black Terns do not normally live or breed in the United Kingdom. They once bred there in large numbers, but sadly they are now extinct as a breeding visitor due to widespread wetland drainage. Today they occur as passage migrants between Continental Europe and Africa. The specimens seen in the UK are of the subspecies C. n. niger.
Length:
22cm to 28cm
Wingspan:
57cm to 68cm
Weight:
50g to 86g
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