If seen well, an experienced observer is usually able to distinguish a long-eared owl by combination of its field marks, size and coloration.
However, some potential owl species may be confused for them.
Stygian owls (Asio stygius) (which barely overlap perhaps in northern Mexico) is larger with partially bare toes and generally darker with inky and more boldly patterned plumage, with often nearly the enter facial mask appearing off-black.
Tawny owls, which co-exist with long-eared owls in Eurasia, are unlikely to be mistaken given that they usually appear considerably rounder and bulkier overall (and are indeed slightly larger and much heavier), further possessing a much broader, more rounded head.
The tawny species has no ear tufts, eyes of blackish-brown colour and relatively shorter wings.
In flight, tawny owls show well-fingered primaries (with five apparent emarginations) unlike the squared off wings of the long-eared owl.
The Eurasian eagle-owl (Bubo bubo) is far larger and more massive than a long-eared owl with visibly more overdeveloped and  powerful-looking feet and talons and a huge squared-off-looking head with the ear tufts set nearer to the edge.
The eagle-owl is often more heavily patterned on the crown and back with heavy blackish marking but has a less strongly demarked (and shallower) facial disc when compared to the long-eared.
In some parts of the wintering range, other eagle-owls may scarcely abut the wide range of long-eared owls in Eurasia (and perhaps Northwestern Africa) but are usually distinguishable (similarly as in the Eurasian species) by size differences, plumage characteristics and, occasionally, habitat preferences.
Asian fish owls, which are essentially a subset of eagle-owls, are generally also much larger than long-eared owls with tousled looking ear tufts, have less variable coloring and often have feathering over only part of their tarsi.
In North America, great horned owls (Bubo virginianus), yet another type of eagle-owl in all but name, have a squarish head and more widely separated ear tufts.
Like other Bubo species, great horned owls are also perceptibly larger and more massively built than any long-eared owl (despite being smaller than the Eurasian eagle-owl).
Great horned owls also have typically heavily barred, rather than streaked, underparts.
Scops and screech owls are much smaller than long-eared owls, as well as differently marked (often with more individual varying overall coloring, i.e. from gray to brown to rufous) and usually have rather short ear tufts.
Marsh owl (Asio capensis) (rare overlap perhaps in northern Morocco) is generally brown with quite different looking fine mottling or barring below and has brown eyes and tiny ear tufts.

Over much of its range, long-eared owls occur with the related short-eared owl, the latter species averaging slightly larger.
Much has been written about distinguishing them in the field, though, if seen well, the resemblance between the species is not particularly strong.
Furthermore, the two species differ in habitat preferences, with the short-eared owl often favoring (where available) any kind of entirely treeless, open habitats (including many wetlands and Arctic tundra as well as steppe, prairie and extensive meadows), often avoiding the edge habitats favored by the long-eared.
However, in dim light, at a distance or in flight, confusion is certainly possible.
In both long-eared and short-eared owls, the flight style when seen has a distinctive, erratic and buoyant flapping quality that many birdwatchers considered reminiscent of a moth.
At rest, the ear-tufts of the long-eared owl serve to easily distinguish the two (although long-eared owls can sometimes hold their ear-tufts lax).
The iris-colour differs: yellow in short-eared, and often orange in long-eared.
Furthermore, the black surrounding the eyes is vertical and slight on the long-eared, and horizontal and far more conspicuous on the short-eared.
Overall, the short-eared owl tends to be a paler, sandier-looking bird than the long-eared, lacking the darker and more exten
If seen well, an experienced observer is usually able to distinguish a long-eared owl by combination of its field marks, size and coloration. However, some potential owl species may be confused for them. Stygian owls (Asio stygius) (which barely overlap perhaps in northern Mexico) is larger with partially bare toes and generally darker with inky and more boldly patterned plumage, with often nearly the enter facial mask appearing off-black. Tawny owls, which co-exist with long-eared owls in Eurasia, are unlikely to be mistaken given that they usually appear considerably rounder and bulkier overall (and are indeed slightly larger and much heavier), further possessing a much broader, more rounded head. The tawny species has no ear tufts, eyes of blackish-brown colour and relatively shorter wings. In flight, tawny owls show well-fingered primaries (with five apparent emarginations) unlike the squared off wings of the long-eared owl. The Eurasian eagle-owl (Bubo bubo) is far larger and more massive than a long-eared owl with visibly more overdeveloped and  powerful-looking feet and talons and a huge squared-off-looking head with the ear tufts set nearer to the edge. The eagle-owl is often more heavily patterned on the crown and back with heavy blackish marking but has a less strongly demarked (and shallower) facial disc when compared to the long-eared. In some parts of the wintering range, other eagle-owls may scarcely abut the wide range of long-eared owls in Eurasia (and perhaps Northwestern Africa) but are usually distinguishable (similarly as in the Eurasian species) by size differences, plumage characteristics and, occasionally, habitat preferences. Asian fish owls, which are essentially a subset of eagle-owls, are generally also much larger than long-eared owls with tousled looking ear tufts, have less variable coloring and often have feathering over only part of their tarsi. In North America, great horned owls (Bubo virginianus), yet another type of eagle-owl in all but name, have a squarish head and more widely separated ear tufts. Like other Bubo species, great horned owls are also perceptibly larger and more massively built than any long-eared owl (despite being smaller than the Eurasian eagle-owl). Great horned owls also have typically heavily barred, rather than streaked, underparts. Scops and screech owls are much smaller than long-eared owls, as well as differently marked (often with more individual varying overall coloring, i.e. from gray to brown to rufous) and usually have rather short ear tufts. Marsh owl (Asio capensis) (rare overlap perhaps in northern Morocco) is generally brown with quite different looking fine mottling or barring below and has brown eyes and tiny ear tufts.
Over much of its range, long-eared owls occur with the related short-eared owl, the latter species averaging slightly larger. Much has been written about distinguishing them in the field, though, if seen well, the resemblance between the species is not particularly strong. Furthermore, the two species differ in habitat preferences, with the short-eared owl often favoring (where available) any kind of entirely treeless, open habitats (including many wetlands and Arctic tundra as well as steppe, prairie and extensive meadows), often avoiding the edge habitats favored by the long-eared. However, in dim light, at a distance or in flight, confusion is certainly possible. In both long-eared and short-eared owls, the flight style when seen has a distinctive, erratic and buoyant flapping quality that many birdwatchers considered reminiscent of a moth. At rest, the ear-tufts of the long-eared owl serve to easily distinguish the two (although long-eared owls can sometimes hold their ear-tufts lax). The iris-colour differs: yellow in short-eared, and often orange in long-eared. Furthermore, the black surrounding the eyes is vertical and slight on the long-eared, and horizontal and far more conspicuous on the short-eared. Overall, the short-eared owl tends to be a paler, sandier-looking bird than the long-eared, lacking the darker and more exten
Long-eared owl