The entire upperparts from the crown to the lower back and wing-coverts are a uniform sooty blackish-brown, with scattered small white spots and greyish flecks.

[3] A high degree of sexual dimorphism is present, whereby the body mass and length is significantly larger in females than in males.

[3] In southern Africa this species generally prefers marshes and vleis where there are patches of tall, rank grass and other vegetation but it may also be found in fynbos, renosterveld and acacia scrub close to water.

It becomes active after sunset and hunts during the night, only if prey is scarce, will they fly during the early morning or late afternoon.

The preferred prey of the African grass owl are rodents and other small mammals normally weighing less than 100 g (3.5 oz) and taken from the ground.

[5] In southern Africa recorded prey items include Duthie's golden mole Chlorotalpa duthiae , African marsh rat Dasymus incomtus, Cape mole-rat Georychus capensis, vlei rats Otomys spp, multimammate mice Mastomys spp, Southern African hedgehog Atelerix frontalis, elephant shrews, hares and bats.

The two to four white eggs are laid at two-day intervals and are incubated solely by the female while the male supplies the food.

[1] However, in South Africa the species is regarded as vulnerable because habitat degradation through ploughing, grazing, draining and burning; the population in the country is considered to be fewer than 5,000 individuals.

[6] To combat their state of vulnerability in South Africa, programmes of captive breeding and release for the African grass owl were tested and studies revealed that this may be a possible effective conservation strategy.

However, reintroduction of the African grass owl is not a simple process because supplementary feeding is required and the habitat must be suitable and contain sufficient prey.