January 10, 2023
Recently, a Short-eared Owl was observed on the Willits Mitigation Lands. It was captured on a wildlife camera that was facing a regularly used perch in the middle of the valley. This caught my attention immediately because, although fairly common and widespread, this species has yet to be documented on the property by our staff. It was early in the evening and waterfowl can also be seen in the video flying to their roosting sites.
Short-eared Owls are associated with open grassland habitats such as wetlands, meadows, and pastures. They are more ‘diurnal’ than other owl species, active during late afternoons and early evenings. The majority of their diet consists of small mammals. Common grassland birds including Killdeer, Western Meadowlarks, and Red-winged Blackbirds make up just five percent of their diet. The owl that appears on the video is probably actively hunting for meadow voles. A study conducted in Ohio on Short-eared Owl winter foraging behavior found that the high frequency of voles found in their diet can be attributed to the owls specifically targeting voles over other readily available prey (Colvin and Spaulding 1983). This is because it is more energy efficient to hunt larger voles and pass on smaller field mice and shrews. Short-eared Owls hunt by long, coursing flights just a few feet above the vegetation. They also have the ability to hover for short periods of time before dropping on their prey. They will also listen and watch for prey from low perches and fence posts.
These medium-sized owls have brown spotting on their back and buffy/white underparts. Their heads are rounded, and they have a pale facial disk with yellow eyes that are surrounded by black rims. They have broad wings that are pale on the underside with a dark marking on its ‘wrist.’
Short-eared Owls are one of the few owls that construct their own nest. They are ground nesters, scraping a bowl into the ground and lining the nest with vegetation and downy feathers. Nest locations are chosen based on the spot having vegetation thick and tall enough to safely conceal the incubating female. A female Short-eared Owl has an average clutch size of 5 to 6 eggs. In years where vole populations are large and food is abundant, the clutch size increases. After 24 to 29 days of incubation, the hatchlings undergo a rapid rate of development and are able to wander from the nest after two weeks. At around 3.5 weeks, the young owls are fully fledged.
Short-eared Owls have a fascinating breeding ritual. Courtship displays begin in late winter around mid-February when the males start ‘wing clapping.’ A male owl will snap his wings together below his body in a burst of two to six claps per second. They perform this maneuver during display flights. The male climbs rapidly with smooth rhythmic wingbeats and hovers momentarily, vocalizing a courtship song. After hovering, the male descends with a shallow glide that ends in a wing clap before climbing again. The flight culminates in what is described as a ‘sashay flight.’ The wings are held in a dihedral position and the bird enters a rocking descent, swaying side to side. Copulation is only initiated after the female accepts a prey item presented by the male. This is called courtship feeding. The male continues to bring food to the female and young as they are being raised, and both adults will defend the nest.
These open country owls are extremely fun to watch. They are graceful fliers that are capable of quick maneuvers. I have observed them on the coast and in the central valley, but this is my first sighting of one in Little Lake Valley. If you find yourself passing through wide open terrain at dawn or dusk, look out for Short-eared Owls gliding over the grassland with deep, slow wing beats!