[5] Reportedly, birds in the southern part of their range appear marginally larger on average but these size differences are quite subtle and may be considered as a mild case of Bergmann's rule.

[4][12] Pliocene fossil Bubo owls with clear similarities based on osteological characteristics to the modern Verreaux's eagle-owl (most are currently classified as Ketupa cf.

lactea) from South Africa and Tanzania, indicate that the Verreaux's eagle-owl descended from slightly smaller ancestors that increased in size as they diversified from related species.

In addition, it is the fourth longest extant owl (measured from the bill to the tip of the tail), after the great gray (Strix nebulosa), Blakiston's fish and Eurasian eagle-owls.

In comparison, the females of the nominate subspecies of Eurasian eagle-owls and great horned owl (Bubo virginianus) are reported to average approximately 20% and 25% heavier than the males, respectively.

[4][27] Pel's fishing owl (Scotopelia peli), which occurs in west, central and inland southern Africa and may co-exist with the Verreaux's eagle-owl in much of its range (despite favoring wetland and riparian zones surrounded by wooded areas), can attain similar sizes as the Verreaux's eagle-owl but is dramatically different in color (a rather brighter rufous-cinnamon hue) and lacks ear-tufts.

[12] In combination, the characteristics of their pink eyelids, dark eyes, relatively uniform plumage and extremely large size render the Verreaux's eagle-owl as nearly unmistakable.

[4][37] In central Mali, for example, near the extreme northwestern limit of the species range, the habitat that hosts these owls averages less than 55 cm (22 in) of rainfall annually.

[37] They also range into riverine forest adjacent to savanna and small, semi-open woodland surrounded by open country, though they are less likely to inhabit heavily wooded habitats.

[46] Despite normally choosing dense foliage to rest in, sometimes they may sit wherever their hunting path ends from the prior night, including relatively exposed perches.

The wing size of eagle-owls in general limits their flying speed and abilities in the open and so they require perches to execute most of their hunting behaviour.

However, Avery, et al. (1985) also acknowledged that adult monkeys of larger size have verifiably been taken alive by the eagle-owls, so it certainly should not be ruled out that they also take live springhares.

[6][48] Many other mammals taken as prey by Verreaux's eagle-owl are seemingly any encountered except the much larger species, especially those that show a propensity for nocturnal or crepuscular activity.

[86][87] An adult Meller's mongoose (Rhynchogale melleri) weighing about 2,200 g (4.9 lb) which was taken by a Verreaux's eagle-owl on the wing represents the second heaviest known object successfully flown with this species after the aforementioned half-grown vervet monkey.

[95][96][97][98][99] A scientifically-observed attack on an adult male African wildcat (Felis silvestris cafra), which can weigh more than about 4,500 g (9.9 lb), was aborted after the eagle-owl apparently deemed that the felid was too heavy to take flight with.

The species best represented in biomass in the prior study was the black-headed heron (Ardea melanocephala) with several adults estimated to average 1,260 g (2.8 lb) being found among the prey remains.

Perhaps the most widely preyed species reported from this group is the 1,229 g (2.7 lb) helmeted guineafowl (Numida meleagris), which may seasonally dominate the eagle-owl's food in Kenya.

In Ethiopia, thick-billed ravens (Corvus crassirostris), which at 1,500 g (3.3 lb) are possibly the heaviest corvid species in the world, mobbed them vigorously and seemed to consider them a primary threat.

[5][6][48][110] The largest bird to be hunted by Verreaux's eagle-owl is complicated by the fact that they often take relatively small nestlings of larger species, such as ostriches (Struthio camelus) and grey crowned cranes (Balearica regulorum).

[5][104][114] The largest herpetological prey known is the Nile monitor (Varanus niloticus), at a mean mature mass of 5,850 g (12.9 lb), these primarily diurnal reptiles can provide a fulfilling meal but can be hard to subdue even if ambushed unaware.

[48][82][123] The Cape eagle-owl has a fairly strong preference for nesting and hunting within the confines of rocky and mountainous habitats, whereas the Verreaux's is at best sporadic in such areas.

Such prey is not quantitatively significant as a food source but since raptors as a rule are sparsely distributed the habitual visitation of a single or pair of Verreaux's eagle-owl can potentially be devastating to a local population.

[48][82][135][137] Despite its place near the top of the nocturnal avian food chain, in 2013 a remote wildlife camera videotaped a black-backed jackal (Canis mesomelas) attacking and killing a Verreaux's eagle owl at a watering hole.

[48][138] Perhaps even more unexpectedly, an adult bateleur was filmed killing a Verreaux's eagle-owl by day, though whether this was predation or a competitive or anti-predatory attack is unclear.

Usage of a nest site other than those constructed by other birds is considered rarer even than in the horned owl and is viewed as almost exceptional in some parts of this species range.

[37][48] The unusual, massive nest is an enclosed circle of sticks with a side entrance that are often very large relative to the size of the hamerkop, a smallish, compact wading bird.

[48] Species known to be successfully displaced from their nests have ranged up in size to lappet-faced vultures (Torgos tracheliotos), which are more than three times heavier on average than the Verreaux's eagle-owl.

One such group consisted of five birds together, including two parents and three owls from the preceding past three years and apparently the younger eagle-owls even helped bring food for the chick once the egg hatched.

[46][48] That young birds usually leave the nest before they can fly would appear to endanger them but the threat and distraction display of parent eagle-owls are apparently often successful.

[1][37][82] The greatest regional stronghold for Verreaux's eagle-owls is seemingly east Africa, in countries such as Kenya, which may have numbers comparable to pre-colonial times.