The Long-eared owl (Asio otus) is one of the most widely distributed and most numerous owl species in the world. While all owls do not build their own nests, Long-eared owls like to use nests that are built by other animals, especially favoring those built by corvids. These owls are also unique in that they are partially for regular roosts that are often shared by a number of Long-eared owls at once.
The Long-eared owl is a rather slim and long-winged bird with usually prominent erectile ear tufts, which are positioned closer to the center of the head than in many other types of owl. In general coloration, the Long-eared owl is often considered a hue ochraceous-tawny with a grayish or brownish wash variably manifesting. The base color is commonly overlaid with variable blackish vertical streaks (and occasionally spots), which are usually more apparent about the wings and back. The scapulars are usually marked whitish, which provides further contrast when seen against the base color and blackish markings. The wing's dark carpal patches can also display broad panels of buff or almost orange on the wings across the base of primaries. On the underside, the body tends to be a somewhat paler ochraceous-tawny compared to the upperside. Long-eared owls tend to have dusky streaks on the upper breast, below which they may be heavily marked with herring bone pattern. There is much individual and regional variation in markings with owls dwelling in more extensively forested regions tending to be of a darker hue, often so densely washed above as to appear largely dusky brown on the back and the underside largely overlaid with bolder dusky-blackish marks. Meanwhile, in some desert-like regions, the plumage may tend towards a somewhat more washed out look, at times appearing fairly cream or yellowish, with sparser and lighter dusky markings overall. The facial disc is visibly well developed and variably colored (see subspecies) in the species, rimmed dusky often with white running down along the center through the bill, while at times the white lines form a “moustache” and/or extending to the inside of the facial disc rim. The ear tufts are usually dusky in front and paler tawny on the back. Long-eared owls possess a blackish bill color while their eyes may vary from yellowish-orange to orange-red, tarsi and toes are feathered.
Long-eared owls breed in many areas throughout Eurasia, as well as in North America. Northern populations are migratory and wander south in autumn. Southern birds are sedentary. Long-eared owls prefer open landscapes with groups of trees, hedges, or small woods, as well as pastureland with rows of trees and bushes, any type of forest with clearings, forest edges, semi-open taiga forest, swampy areas and bogs, orchards with old fruit trees, parks, even gardens and timbered areas in villages, towns or cities. In many parts of the world, Long-eared owls have even adapted to deserts, though more commonly semi-desert, and may nest and roost in available oases and hunt prey over the open desert ground.
Long-eared owls are nocturnal with most activity at dusk. During the day they usually roost on a branch, closer to the trunk within dense foliage. When approached, the owl will freeze with its body stiffly upright, eyes closed to narrow slits, and ear tufts erect. This is called the “tall-thin position”. If approached closer, the owls will alternately open and close their eyes (apparently trying to fool potential predators into thinking the owl is still at rest), finally lowering ear tufts, fluffing body plumage, and flying to another roost. Unlike many owls, Long-eared owls are not strongly territorial and often roost in groups that may include up to 6 to 50 owls at times. They tend to roost in the depths of the "darkest stands of trees" in order to conceal their presence from predators. Long-eared owls hunt mainly on the wing, flying low and fairly slowly. Once prey is spotted, the owl's flight suddenly stalls, and then they quickly drop with talons spread to pounce on prey. Long-eared owls communicate with the help of various vocalizations. The song of the male is a deep 'whoop', which is repeated at intervals of several seconds. Females give a weaker, less clear, and much higher-pitched song with a nasal quality. Females usually call only in a duet with males during courtship, but also when the nest is selected and during incubation. When disturbed near the nest with owlets, both parents may utter a series of tinny tones 'watt-watt-watt-watt', hiss, or snap with their bills. Other calls produced by these birds include cat-like, hoarse 'jaiow' or high 'yip-yip' notes and clapping sounds; fledglings call with high-pitched 'feek, peeyee' and 'pzeei' notes.
Long-eared owls breed are carnivorous specialized predators; these birds focus their diet almost entirely on small rodents, especially voles, which often compose most of their diet. They also hunt various small mammals, small birds, small snakes, lizards, and insects.
Long-eared owls usually form monogamous pairs (one male to one female). Breeding usually occurs from March through May. Males claim their territory by singing and displaying flights with wing clapping. Females typically take on the duty of inspecting potential nesting sites and duets with their mate; perched on a chosen nest, she sings to contact the male. Long-eared owls usually use nests that are built by other animals hidden in the dense vegetation of a tree. They prefer stick nests of large birds such as raptors and herons. Generally, the female lays 3-5 eggs that are incubated for about 27-30 days. The female alone incubates while the male provides food, which is brought directly to the nest. The chicks hatch helpless and blind (altricial); their eyes open at 5-7 days and they are brooded by the mother for about 2 weeks, often while the male perches nearby and watches over. The female alone feeds the chicks and does a majority of nest defenses. The young leave the nest at 20-27 days of age but are initially flightless, often climbing about surrounding branches. At this stage, they are called "branchers". Quite often owlets fall to the ground, but they are usually able to climb back up using their claws and bill with heavy wing flapping. At about 35-37 days, they are fully-fledged and can fly well. The owlets often follow their parents and are fed by them for up to about 2 months. Reproductive maturity is usually reached when they are 1 year old.
Long-eared owls are common and widespread in many regions. Local threats typically include pesticides, persecution by humans, high nest predation, and loss of habitat. Many Long-eared owls are also often killed by road traffic.
According to the IUCN Red List, the total Long-eared owl population size is around 2,180,000-5,540,000 mature individuals. The European population consists of 304,000-776,000 pairs, which equates to 609,000-1,550,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.
