The Black Tern is one of the few we have here

Al Lowe
Contributor

The Black Tern is one of the few terns which we have here in Northwestern Ontario. It is primarily an inland bird which breeds mainly on inland marshes, small lakes and rivers. It is fairly common all across the eastern part of North America.
Most of the terns we know are white or light-coloured. This, however, is one of the few species which is dark. In the summer, the head and underparts of this tern are black. The wings, back and tail are a sort of sooty grey.
Like many birds, this one changes its colours for the winter - and the change is quite drastic. The forehead, a wide collar, and all the underparts become white. The back and wings become light grey. Young birds are quite similar. You are not likely to see this bird in the winter, anyway, since it spends all that time in South America.
This tern does not feed on water animals most of the time. Although it does take minnows, crayfish and so on, the bulk of its diet consists of insects. On ponds and marshes, and on prairie sloughs, it is usually found patrolling over the grass, catching flies, moths, dragon flies, grasshopper and others on the wing.
The Black Tern usually builds its nest on, or very close to, the water. A pile of floating reeds and grass is quite common. However, it also favours the tops of beaver or muskrat houses, and, once in a while, even on dry land. They don’t usually build a nest at all, but just scrape out a hollow in the vegetation.
The young birds only stay in the nest for a few days. But if some danger threatens, the old bird will give a series of loud, high pitched screeches. The young ones skip out of the nest right away, and paddle away among the plants. When the mother is satisfied that all danger is past, she will call to them softly and they come back to the nest.
This bird is not confined to North America, but breeds all around the world in temperate zones. With its diet of insects, it is useful wherever it is found.
The Black Tern (Chlidoias niger) is one of the real acrobats of the bird world. It zigzags with great skill, seems as buoyant as a butterfly, and can skim slowly over the surface of the water or a field, for hours. As it flies just over the tops of the waving grass, or the lake, it is ready to swoop down with great precision to pick an insect right out of the vegetation or the air.