Black Tern
Chlidonias niger

Written and compiled by Lindsey Hernandez

Painting by John James Audubon, from The Birds of America
Photo by Andrej Chudy

The Black Tern is one of the smallest terns, 9.1–14.2 in (23–36 cm) long, with a wingspan of 22.4–23.6 in (57–60 cm). They are larger than least terns, but smaller than common terns. The Black Tern is usually visible near freshwater marshes in Texas July through September, during their mating season, before flying south to tropical shores for the winter.

Adults in breeding plumage are dark gray above with black heads and black underparts. They make a striking difference between the average white shorebird. The underwings and undertail coverts are pale. Nonbreeding adults are gray above, whitish below, with a dusky crown, ear-patch, and mark at the side of the breast. Juveniles are similar to nonbreeding adults but with a brown scaled pattern to the upperparts.

Their delicate form and neatly pointed wings provide tremendous agility as these birds flutter and swoop to pluck fish from the water’s surface or veer to catch flying insects, much as a swallow does.

A highly social bird, Black Terns nest in large freshwater marshes, in small, loose colonies. Early in season, pairs or small groups ascend in spiraling high flight above colony, then glide down to their precarious, floating nest site. Black Terns arrive in pairs, and participate in high flying courtship displays only at the beginning of mating season. Courtship displays quickly change to the male gallantly foraging and then feeding his female mate who is tailing behind him.

Their nest will typically be low in marsh and floating mat of plant material, on old muskrat house or debris, or on ground close to water. Both parents build the nestNest (built by both parents) may be substantial platform of marsh plants, or simple depression with a few bits of vegetation added, very close to water level. Their  eggs are often damp.

In the last half-century, this species has lost about half its North American population. Loss of nesting habitat owing to drainage of wetlands is one likely cause. Runoff of farm chemicals into nesting marshes may affect hatching success.

In Central American wintering areas, Black Terns may have been affected by sharp declines in prey species, especially small fish. Key to the conservation of this species is protection and restoration of freshwater wetlands from the Great Lakes region through the prairie provinces of Canada, where declines have been severe since the 1960s.

In Marshallese folklore, a black tern flying over the island and crying out brings good luck and is a sign that next year’s food will be abundant.

Sources Include: Marshallese Folklore Types, All About Birds, and audubon.org.