Breeding Swallows

Barn Swallow (juvenile)

Six species of swallows breed in the Ottawa area, and most are easy to find. Tree Swallows like open fields and agricultural areas, particularly where there are lots of natural tree cavities or nest boxes. Barn Swallows also like open fields and farms, but need water in order to build cup-shaped nests of mud on the walls of man-made structures, such as the undersides of bridges and in the rafters of barns or other open structures. Purple Martins nest almost exclusively in man-made houses that can be single gourd-shaped boxes or large multi-cavity apartments; it is difficult to find colonies away from human settlements these days, at least in the east. Northern Rough-winged Swallows nests in burrows or cavities in various substrates, particularly near water, and often use circular drainage holes in the cement walls along bridges and canals. Bank Swallows also nest in burrows and cavities, but are much more particular about using vertical cliffs or banks along streams, lakes, or man-made quarries where they nest in colonies of 10 to 2,000 pairs. Finally, Cliff Swallows – personally the most difficult swallow species for me to find in Ottawa outside of a few known colonies – nest on buildings, bridges, and other man-made structures close to fields or pastures for foraging, and a source of mud for nest building.