New York Status: Endangered
Federal Status: Not Listed
Short-eared owls are medium size owls with small ear tufts on the top of the head. They have round, beige facial disks similar to those of barn owls. The underparts are white/buff (male) or tawny/rust (female), and streaked with brown, while the back is brown and mottled with white. When perched, the wings extend beyond the tail and in flight, the undersides of the wings show dark markings on the wrists and wing tips. The short-eared owl's flight is frequently described as "moth or bat-like" because it flies low over grasslands or marshes, moving back and forth with unhurried, irregular wing beats.
Short-eared owls are the most diurnal (active during the day) of all the northeastern owls. They are most often observed in the late afternoon and at dawn or dusk. These birds eat primarily small mammals, but they occasionally take small birds and the young sometimes eat insects. When hunting, they dive from perches or fly low over the ground and pounce on prey from above, sometimes hovering briefly before they drop.
Short-eared owls are birds of open country including grasslands and marshlands. They often opportunistically inhabit areas where small mammals, especially meadow voles (Microtus pennsylvanicus), are abundant. Their breeding sites, the number of wintering birds, the number of nesting pairs, and the number of eggs or young may change from year to year based on the food supply. Breeding occurs in March through June when both sexes begin defending territories and courting with elaborate flight displays that include wing-clapping, exaggerated wing-beats and skirmishing.
Nests are placed on the ground where the female creates a cup and lines it with grasses and down. Four to nine eggs are typical, but clutches as large as fourteen have been reported in years of peak small mammal abundance. Incubation, which is done by the female alone, lasts about a month. The eggs hatch asynchronously and fledging occurs about a month later.
In winter short-eared owls gather in open habitats that support large numbers of voles such as both fallow and cultivated grasslands, marshlands, and landfills. When food is abundant they may form large communal roosts of up to 200 birds in sheltered sites ranging from conifers to grassy tussocks and abandoned quarries.
Deep snow and ice may reduce the availability of prey locally and cause the owls to abandon wintering areas occupied earlier in the season. However, where food remains plentiful into the spring and summer, wintering areas may become breeding sites.
Distribution and Habitat
Short-eared owls are widely distributed breeding in marshes, grasslands, and tundras throughout North America and Eurasia, and on every continent except Australia and Antarctica. They are also found on islands such as Iceland, the Hawaiian Islands, the Greater Antilles, and the Galapagos. Within their extensive global range they occur in open areas where small mammals are abundant, favoring habitats such as prairies, coastal grasslands, heathlands, shrub-steppe, and tundra.
Although there are scattered breeding records in the east as far south as Virginia, New York is at the southern edge of this owl's breeding range. Northern populations are believed to be highly migratory, and there is a marked increase in the number of birds in New York in the fall and spring. Short-eared owls are more common as winter residents in New York State. As breeders they are very rare, being largely limited to the St. Lawrence and Lake Champlain Valleys, the Great Lakes plains and the marshes of Long Island's south shore.
Early in the twentieth century Eaton called the short-eared owl "one of our commonest owls" outnumbering all other owls in lowlands and marshy areas. By 1974 it was already considered a local breeder, declining in numbers. A comparison of historical and modern breeding records suggest that this species may have been lost as a breeder in many areas including eastern Suffolk County and the upper Hudson Valley. However, knowledge of their status and distribution may be incomplete because they occur in some parts of the state that are sparsely populated, breed early in the season, and hunt late in the day.
During the second New York State Breeding Bird Atlas, this species was found at a total of 24 survey blocks resulting in a 33% total decline from the first atlas. The most substantial losses occurred on Long Island with the species detected in only one survey block during the second atlas, as compared to nine blocks during the first.
Short-eared owls winter, sometimes in significant numbers, at concentration areas located throughout the state including the Finger Lakes region, the Lake Ontario lake plains, especially in Jefferson County, several sites in the Hudson Valley, and on the shores of Long Island. Historically, many winter concentration areas were also documented as breeding areas.
In the Northeast region, six of the thirteen states list short-eared owls as endangered while one other includes them on their state list at a lower level of conservation concern. Most biologists believe reforestation along with the loss of large, intact grasslands and other open habitats are largely responsible for this species decline.
Management and Research Needs
The conservation of short-eared owls in New York depends on protecting relatively large, open sites that support small rodents. Except for a few large marshes, most of the nest sites recorded in recent years have been found on farms, typically in active hayfields or pastures where the nests and young birds are sometimes mowed or plowed. Once abandoned, agricultural sites rapidly become unsuitable for owls because they succeed to woodlands or are replaced by development. In order to protect short-eared owls it will be necessary to identify suitable nesting sites that can be managed for small rodents and owls. Such management will likely have the added benefit of protecting other imperiled grassland birds with similar habitat requirements.
Recent efforts have been made to more closely monitor and identify wintering raptor concentration areas throughout New York State, with the short-eared owl included as a primary target species. This research has led to a better understanding of the importance of these concentrations areas to the species and their response to changes in habitat and environmental conditions. Light has also been shed on the migratory patterns and breeding areas of short-eared owls wintering in New York State.
Efforts have also led to the conclusive documentation of winter site fidelity for this species at two locations. Information gathered will help guide conservation efforts for this and other grassland species and potentially allow resource managers to minimize impacts of development and habitat conversion in the state.