The Pygmy Falcon, or African Pygmy Falcon (Polihierax semitorquatus), is a falcon that lives in eastern and southern Africa and is the smallest raptor on the continent. As a small falcon, only 19 to 20 cm long, it preys on insects, small reptiles, and small mammals.
Adult pygmy falcons are white below and on the face, grey above. Females have a chestnut back. There are white "eye spots" on the nape. The tail is barred black and white.
The pygmy falcon inhabits dry bush. In Kenya, pygmy falcons nest in white-headed buffalo weaver nests, and the ranges of the two birds coincide. In southern Africa, they are found around red-billed buffalo weaver nests but predominantly nest in the vacant rooms of sociable weaver nests, which are large and multichambered—even if the sociable weavers still have an active colony in the nest. Despite being bird-eaters and bigger than sociable weavers, the pygmy falcons largely leave the latter alone, though they do occasionally catch and eat nestlings and even adults.
Pygmy falcons occasionally engage in polyandrous relationships, where there are more than two adults living together and tending nestlings. There are four potential reasons for this behavior: defense, co-operative polyandry, delayed dispersal of offspring, and thermoregulation (warmth). Corroboration for the last is that in winter African pygmy falcons nest further inside the nest of sociable weavers, where there is better insulation.