A forest-dependent species, it occurs in primary rainforests across western, central and (marginally) eastern Africa where it preys on birds and tree squirrels.

[4] A fairly small eagle, under current classification, Cassin's hawk-eagle is the smallest member of the Aquila genus.

[8] The visual similarities with other hawk-eagles can be explained by convergent evolution[8] but there is still some work being done on booted eagle phylogeny in general, so this may change in the future.

[10][1] Restricted to primary rainforest, A. africana is thought to have been more widespread in the past but its distribution has since contracted with the continued destruction of the Guinea-Congolian Forests.

[14] Both sexes help construct the nest with sticks more than 25 m (82 ft) above the forest floor in the canopy of a tree where it is lined with fresh foliage.

[14] When the stomach contents of collected specimens have been examined they have been found to contain the remains of birds and tree squirrels,[4] although it is possible that other vertebrates are eaten too.

Cassin's hawk-eagle is a proposed partner in a visual mimicry system where it is the model to the Congo serpent eagle (Circaetus spectabilis) mimic.

[4] These proposed mimicry systems are unusual in that they involve two predatory species that show remarkable similarity in plumage colour and pattern as well as in body size and proportions.

A. africana and C. spectabilis differ greatly in diet though, with the former preying on forest birds and tree squirrels and the latter predominantly on reptiles like snakes.

[15] Thiollay (1985) suggests that lumbering be restricted to removing only small patches of forest to prevent too much degradation,[13] however this strategy is unlikely to be followed, unless enforced, due to the reduced economic gain.