The long-eared owl is a medium-sized owl, 31–40 cm (12–16 in) in length with an 86–100 cm (34–39 in) wingspan and a body mass of 178–435 g (6.3–15.3 oz). It has erect blackish ear-tufts, which are positioned in the center of the head. The ear-tufts are used to make the owl appear larger to other owls while perched. The female is larger in size and darker in coloration than the male. The long-eared owl’s brownish feathers are vertically streaked. Tarsus and toes are entirely feathered. Eye disks are also characteristic in this species. However, the eye disks of A. otus are darker in color or rusty-orange. This nocturnal species is perhaps most easily seen perched in a tree in its daytime roost, sometimes in small groups during the winter months.