Short-eared Owl

Name

The genus name Asio is Latin for “a horned owl.” The species name flammeus is Latin for “fiery” or flame-colored,” referring to this owl’s plumage. The common name reflects their short ear tufts (relative to the long-eared owl). 
   

General Description 

Short-eared owls are streaky, yellow-eyed owls with the appearance of a round head. Their coloring successfully mirrors that of the grassland vegetation they live amongst, and their overall plumage impression is golden, brown, and cream. Males are generally less colorful than the females, though this is not a hard and fast rule. They can be seen prowling over grasslands, marshes, and open fields at dawn, dusk, and during the day. In flight they have a characteristically light, moth-like wingbeat, and hold their wings in a slight “V” above their head, called a dihedral.

Similar species: Long-eared and barn owls can be confused with short-eared owls in flight. Long-eared owls do not show as clear of a dihedral, appearing flatter in profile when they fly, and they have mottling on their underside rather than streaking like the short-eared owl. Barn owls have comparatively little markings on their undersides, and they lack the dark wrist markings of the short-eared owl. 
 

Habitat

The short-eared owl is an open-habitat species. During the winter this includes fallow fields, hay meadows, pastures, marshes, and other sites that offer adequate shelter from the elements and freedom from human disturbance. In the summer they can be found breeding in a wide variety of habitats, including prairies, tundra, grasslands, marshes, and dunes. During the breeding season short-eared owls prioritize sites that offer optimal hunting opportunities, quality nesting habitat, and sufficient places to rest. Summer sites that offer year-round resources may double as an overwintering ground and vice versa. 
 

Feeding 

Short-eared owls are mammal specialists. A review of 10,000 pellets collected through 25 different studies in various locations revealed that mammals composed 94.8% of the identified prey, with Microtus voles making up more than 60% of that mammalian subset. Short-eared owls can take non-typical prey when necessary such as young muskrats, rabbits, and insects. Short-eared owls that live in places with an absence of voles have alternative diets; for example, coastal-dwelling populations feed on a high proportion of shorebirds, seabirds, and other marine-based prey, while short-eared owls in Ireland feed primarily on wood mice and brown rats, as voles are scarce. 

Typical feeding behavior consists of flying less than two meters above the vegetation and angling into the wind to take advantage of lift. Short-eared owls are highly maneuverable, capable of turning on a dime and hovering directly above prey before attacking. Their long broad wings and slight dihedral allow them to remain airborne for long periods of time as they sweep over open fields in search of prey. 
 

Nesting

Short-eared owl courtship is a breathtaking scene to witness, complete with impressive flights and auditory adornments to boot. The male will flap his way up to a desired height and then drop like a stone while bringing his wings together rapidly to produce a loud clapping sound while also hooting. Males will repeat this dance many times, sometimes performing for over an hour. 

Short-eared owls are ground nesters, and one of the few owls to construct their own nest. The female will create or find a shallow depression in the ground and line it with grasses, feathers, or other suitable materials. Clutch size ranges from 1 to 11 eggs, with specific averages varying with latitude and prey abundance. Incubation and brooding are completed by the female while she and the nestlings are fed by the male. Incubation lasts roughly 21-31 days, and growth is rapid with fledging occurring at just 12-14 days of age. The young owls will scatter throughout their parent’s territory, therefore increases the probability of survival for at least some of the brood. Parents play an active role in harassing intruders by dive-bombing or pretending to have a broken wing so as to distract predators away from their vulnerable offspring. 

Short-eared owls, like barn owls, are capable of double clutching if the first clutch fails and have even been documented raising two successful broods in one year. However, even with such adaptive breeding habits, short-eared owls have fairly low reproductive success primarily because their ground-nesting habits put them at risk for predation and human disturbance from some agricultural practices. 
 

Migration

There is still a great deal to be learned about the movement ecology of short-eared owls. Experts agree that most populations likely migrate, however the details are poorly understood. Based on movement studies conducted thus far, short-eared owls display a combination of site fidelity (returning to the same sites year after year) and nomadism, suggesting that this is a species with flexible movement patterns. This could be due to the cyclical population fluctuations of voles, as some other species dependent on cyclical rodents such as snowy owls exhibit similar adaptability. Short-eared owls can be seen year-round in a horizontal strip across the northern United States, because of overlap between summering and wintering grounds.