Swallows (family Hirundinidae) have pointed wings and forked tails; their heavy flight muscles give them a characteristic “broad-shouldered” appearance. Their flight is rapid, smooth and flowing. Most species eat exclusively insects caught in flight. Nesting habits vary within the family: some species make mud nests; many species are gregarious nesters.
Globally there are ninety swallow species, distributed among all of the continents except Antarctica. There are nine species of swallows in North America; seven of these breed in Saskatchewan. Purple martins (Progne subis) nest colonially in nest boxes or cavities of dead trees in southern Saskatchewan, but face stiff competition from the introduced European starlings for nest sites. Purple martins are the largest swallow, with unmistakable bluish-black plumage. Tree swallows (Tachycineta bicolor) are stocky and broad-winged; adult males have distinctive blue-green backs, gray brown tails and wings, and white underparts. They nest in nest boxes and treed areas of Saskatchewan. Violet-green swallows (T. thalassina) are found in the badlands of southern Saskatchewan and in the Cypress Hills (Ft. Walsh); they are distinguished from the tree swallow by their brilliant green to purple plumage with white sides. Northern rough-winged swallows (Stelgidopteryx serripennis) are found in banks of watercourses and gravel pits in the grasslands and parklands of Saskatchewan. They are larger and stockier, with shorter tail and wings than bank swallows (Riparia riparia), which are often found close by, and have a short bill and brown plumage. Bank swallows are small-headed and slender with thin wings, white underparts, and a long notched tail. They are found in cutbanks of watercourses, roads and railways, and gravel pits. Cliff swallows (Hirundo pyrrhonota) nest in mud cups in cliffs, and on bridges and buildings in southern Saskatchewan and around Lake Athabasca. They have a short, square tail, dark throat, buffy rump, and chestnut-coloured face and nape. In contrast, the cosmopolitan barn swallow (H. rustica) has a rusty forehead and neck, long, deeply forked tail, dark iridescent blue-black upperparts, and buffy to cinnamon underparts. It nests in buildings and on bridges (even in machinery) throughout Saskatchewan.