Black Tern

Unlike the familiar terns of the genus Sterna, Black Terns rarely plunge-dive. Instead, they fly with distinctive buoyant and erratic flight, almost bat-like, often swooping low to pick up some food item from the surface of shallow water.

Preferred breeding habitat of Black Terns includes freshwater marshes, prairie sloughs, and lake edges. The male performs a display flight where he carries a small fish or dragonfly in view of potential mates. A female that accepts the invitation follows him to a perch where he feeds her the prize. Black Terns are semi-colonial nesters and only defend a small territory a few feet around the nest. Nests may be as close as 1 yard apart, but more typically they are 15 to 60 feet apart, in clusters of 10 to 50 nests. Both parents make the nest. The nest sites can be on top of muskrat houses, floating root masses, driftwood, or boards. Sometimes Black Terns may use an old coot or grebe nest. They do not usually carry nest materials in flight, but instead heave dead vegetation up from the water and arrange it in a small cup at the nest site. Both parents incubate the eggs. Nesting success is variable; nests are so flimsy and close to the water that they are often destroyed by wind and wave action. Hatchlings are semi-precocial and downy. They move about on the nest for about two weeks, and start to fly at three weeks.

During the breeding season, Black Terns pick insects off of vegetation or capture them in the air, including dragonflies, mayflies, beetles, and moths. They also prey on small fish, mollusks, crayfish, and spiders. Large numbers of terns may hover over meadows and grassy marshes, or follow plows to feed on exposed grubs.

After the young fledge, Black Terns gather at favorable staging sites. Fall migration begins in late July, with the juveniles typically leaving about one month after adults. Singly or in small groups, they pass to the Gulf Coast where they may gather in flocks of thousands. While on the coast and associating with other species of terns, Black Terns feed on small fishes, especially those driven to the surface by underwater predators. Peak migration is in mid to late August. The wintering range is from Panama to Chile. Returning spring migrants reach Canada in mid April to late May.

Black Terns occur locally throughout the northern United States and central Canada. They occur only sporadically and uncommonly throughout the northeast and southern parts of the range and are most abundant in the prairies of the Dakotas, Alberta, Saskatchewan and Manitoba. Black Terns also occur in Europe. The European population winters in the Mediterranean and along the African Atlantic coast.
Black Tern Range Map

Description: The Black Tern is a small, short-tailed, small-billed tern that is easily identified in breeding plumage. At that time it has a black head and body with dark gray wings and tail, and white on the belly and under the tail. In flight the tail is slightly forked, appearing almost squared-off when spread. At rest the wings extend well beyond the tail. The bill is black, and the short legs are dark red.

Adults in winter and immatures have white underparts. The head is white with dark gray around the eyes, ear coverts, and nape. There is a dark patch on the sides of the breast. The wings and tail are uniform gray in all plumages.