Great horned owl

The great horned owl (Bubo virginianus), also known as the tiger owl (originally derived from early naturalists' description as the "winged tiger" or "tiger of the air") or the hoot owl, is a large owl native to the Americas. It is an extremely adaptable bird with a vast range and is the most widely distributed true owl in the Americas. Its primary diet appears to be rabbits and hares, rats and mice and voles, although it freely hunts any animal it can overtake, primarily other rodents and small mammals, but also larger mid-sized mammals, various birds, reptiles, amphibians and invertebrates. In ornithological study, the great horned owl is often compared to the Eurasian eagle-owl (Bubo bubo), a closely related species which, despite the latter's notably larger size, occupies the same ecological niche in Eurasia, and the red-tailed hawk (Buteo jamaicensis), with which it often shares similar habitat, prey and nesting habits by day and is thus something of a diurnal ecological equivalent. The great horned owl is one of the earliest nesting birds in North America, often laying eggs weeks or even months before other raptorial birds.

Horned owl

The American (North and South America) horned owls and the Old World eagle-owls make up the genus Bubo, at least as traditionally described. This genus, depending on definition, contains about one or two dozen species of typical owls (family Strigidae) and is found in many parts of the world. Some of the largest living Strigiformes are in Bubo. Traditionally, only owls with ear-tufts were included in this genus, but that is no longer the case.

Systematics

Mitochondrial DNA (mtDNA) cytochrome b sequence data supports the decision to consider the snowy owl an eagle-owl adapted to Arctic conditions and moving it into Bubo, rendering the monotypic genus Nyctea invalid.

The four fish-owls previously in the genus Ketupa were provisionally moved into Bubo as well. However, the mtDNA cytochrome b data suggests that in this case, to make Bubo monophyletic the Scotopelia fishing owls would also need to be included there. On the other hand, the genus then becomes quite large and ill-defined, and Bubo in the expanded sense seems to consist of two distinct clades. Thus, the fish and fishing owls can alternatively be united in Ketupa if some aberrant eagle-owls – at least the barred, spot-bellied and Usambara eagle-owls, perhaps also Fraser's eagle-owl and maybe others – are moved into that genus too. As some enigmatic eagle-owls remain essentially unstudied and others – e.g. Verreaux's eagle-owl – are of unresolved relationships, more research is needed.