A chunky, martin-like dark blue and reddish-brown cliff swallow with a rusty rump and undertail and a smudgy dark collar that may be incomplete. Colonies of 10-1000 pairs nest under bridges, in culverts, in quarries, and occasionally on cliffs, often near water. After breeding in South Africa, Namibia, and Zimbabwe between September and April, the species migrates to the southern Congo basin for the austral winter. It forages over grassland, lightly wooded savanna, and arid shrubland for insects. The similar Red-throated Swallow is smaller and more slender than the South African Swallow, with white tail spots, a uniform rufous throat, and a breast that lacks dark mottling.