By Kate Redmond
Seven things I didn’t know about Short-eared Owls (Asio flammeus):
- They are a global species, missing from Antarctica and Australia but breeding in Europe, Asia, and the Americas, and wintering (but not breeding) in North Africa. They’re one of our most widely distributed owls.
- They fly long distances, even over oceans, and sometimes land on ships at sea.
- There are 10 recognized subspecies, including Hawai’i’s only native owl, the Pueo, whose ancestors probably flew down from Alaska.
- If a female Short-eared Owl is flushed off her nest, she might whitewash her eggs as she leaves – the smell may camouflage the odor of the nest or discourage predators.
- Their dining habits are gory. They remove the head and guts from their rodent prey and may pull the wings off of birds before swallowing them.
- Males perform a “sky dance” during courtship with aerial acrobatics, vocalizing (“barking”) and wing clapping.
- Their young are called “semi-altricial.” Helpless (but down-covered, not naked) when they hatch, they’re able to hike away from the nest by the time they’re about 15 days old and able to fly about 15 days after that.
Because Short-eared Owls are found in a variety of open-country habitats with short vegetation like grasslands, tundra, dunes, marshes, hayfields, and shrubby fields, they’ve earned regional names like Prairie, Marsh, and Bog Owl. They breed in scattered locations in central and northern Wisconsin but are more commonly seen here in winter. If you’re looking for a place to take a winter walk, try the trails at Forest Beach Migratory Preserve, the northwestern part of Harrington Beach Sate Park, and the Schwengel Waterfowl Production area on Six Mile Road, northwest of Belgium. You might find some Short-eared Owls on the prairies.
With a short neck and tail, Short-eared Owls appear to be all wing. In the summer, they might be mistaken for a Northern Harrier (a.k.a. Marsh Hawk), which lives in the same grasslands and hunts for the same food in a similar fashion (and sometimes steals prey from the owls). Short-eared Owls are brown and streaky; the undersides of their wings are light-colored, and they lack the harrier’s white rump patch. They are between crow-sized and Great Horned Owl-sized, but their bulk is all feathers. They weigh in at a pound or less. (Females are a larger and heavier than males.) Like other owls, Short-eared Owls have a keen sensory repertoire. Raptors’ eyes are located on the front of their head, allowing binocular vision, and their eyesight is sharp.
Like the “horns” of a Great Horned Owl, their “ears” are actually feather tufts; the real ear openings are covered by skin and feathers, and as in many species, ear placement is asymmetrical, which allows owls to triangulate the location of their prey. Audio information is collected via the facial disk, a concave array of feathers around the bird’s eyes. Moving the facial feathers adjusts the amount of sound that is fed to each ear. They have a number of vocalizations (the young even call from within the egg), but their displays are visual, as befits a bird of open spaces.
In springtime, when the breeding season gets under way, and especially in winter, they may be communal, and groups of a dozen or more are common in winter.
During the summer, they hunt day or night, but on their wintering grounds, they are crepuscular – active at dawn and late afternoon/dusk. Voles are their main prey, and they also take mice, shrews, rats, rabbits, and muskrats. In summer, they’ll eat some insects and an occasional bat, and they’ll also hunt for grassland birds and for young gulls and shorebirds along the coast. They mostly hunt from the air, quartering back and forth over a field, sometimes hovering, carried in a stiff, bouncy, mothlike flight by their long, rounded wings. After a successful hunt, they carry their prey with their talons – unusual among owls.
Females make a rudimentary nest on the ground by flattening the grass and maybe laying down a few sticks, and they lay an average of five to seven eggs. The male feeds her while she incubates (their pair bond lasts for one season) and brings food for her to give to the young after the eggs hatch. If her nest is approached, she will try to intimidate or distract the intruder. Since they nest and often perch on open ground, they are vulnerable to attack by foxes, coyotes, dogs, and raccoons, as well as by other raptors.
Short-eared Owls are migratory. Birds from the north move into Wisconsin in winter as most of our breeding Short-ears fly farther south. Their populations reflect the highs and lows of their rodent prey, and they are also nomadic, abandoning areas where prey numbers are low. It’s tough to get an accurate fix on their status.
While they are not federally endangered, their numbers are declining in the southern part of their range in North America, and they are considered endangered, threatened, or species of special concern in most of the upper midwestern and Great Lakes states. In Wisconsin, they are a Species of Greatest Conservation Need (species that have “low or declining populations and are in need of conservation action”). Habitat loss and fragmentation and changing agricultural practices (including increased acreage dedicated to the production of corn for ethanol) are big factors, as they are for other grassland bird species. Their low flight puts them into the path of cars, and they have an affinity for airport runways.
INTERESTING LINKS
http://www.wisconsinbirds.org/plan/species/seow.htm
nice pictures - https://wsobirds.org/apg-seow