[4] Fraser's eagle-owl is now one of twelve species placed in the genus Ketupa that was introduced in 1831 by the French naturalist René Lesson.

[8] Compared with the nominate the subspecies K. p. vosseleri has heavier blotching on the breast and more widely spaced barring on the underparts.

[9] The territorial song of the male Fraser's eagle-owl is a rapid, stuttering and long deep, guttural trill which has been said to resemble the noise made by an electricity generator.

[8] Like most owls Fraser's eagle-owl is a nocturnal bird, roosting during the day hidden by leaves, about 40 m (130 ft) above the ground.

[11] Its main prey is small mammals, such as mice, squirrels and galagos, and it also takes birds, frogs, reptiles, insects and other arthropods as well as occasionally feeding on fruit.

In Gabon they are reported as singing in June–September but breeding seems to take place throughout the year, apparently varying geographically with egg-laying being recorded in February in Liberia, through to December in Uganda and Democratic Republic of Congo.