Short-eared Owls
Jenn Rogers, Mercer County Naturalist

Introduction - For several winters, bird watchers have flocked to the fields of the Pole Farm to observe the visiting short-eared owls. Their presence is a rare treat local birders, because it is one of the few wintering spots for short-ears in New Jersey. The other reason this raptor is a treat: the hours during the day which it is most active. Unlike most night-loving owls, short-eared owls are crepuscular creatures, meaning they are active during dawn and dusk. During these times, the owl can be viewed flying low over the Pole Farm grassland in search of meadow voles, their main food source. Their flight is often described as "moth-like"; their wing flaps slow and deliberate. Their wings reach high above their body during each beat, giving the illusion of a bouncy flight.

Known as the evening owl, marsh owl, and flat-faced owl in some areas, the short-eared owl is one of the most widespread owls worldwide. They are found on every continent except Australia and Antarctica.

Description - Short-eared owls are a medium-sized owl, standing 13 -17" tall. However, they have an impressive wingspan that measures at least three feet. Different observers have described the birdís pattern and coloring to resemble "dead grasses". Their plumage is mostly tawny and brown streaked; the face is buff colored or white. One of their most outstanding features are their eyes. The iris is a piercing (bright) yellow, bordered by a pure black mask. Their eyes are so stunning that their scientific name is Asio flammeus, "flammeus" meaning flaming or fiery in Latin. Short-eared owls also have black beaks and black talons.

Habitat & Ecology - Large tracts of grassland, pasture, and coastal marshes fit the bill for short-eared owls, in both summer and winter months. Short-eared owls rely on open-county to roost, hunt, and nest. When snow covers the ground, short-ears may roost in evergreen trees.

The majority of the short-eared owlís diet consists of rodents. Hunting is done on the wing, the owls flying less than 10 feet above the ground. Occasionally, they hunt from a perch or hover high in the sky. Prey is detected mainly by hearing and is aided by vision. Food items include small mammals, such as shrews, moles, rabbits and mice, and a variety of birds. Their main prey are voles. In the winter, these raptors may hunt communally, if food is abundant.

Short-eared owls are one of the few owl species to build a nest. Nests are built on the ground, by the female and consist of a scrape in the soil lined with a few grasses and feather down. In North America, their breeding range extends from Alaska to Canada, and south to the Great Lakes and central California. Some breeding habitat remains in the Northeast, but sites fluctuate with prey populations.

Winter is the social season for short-ears. Where prey is abundant they may roost and hunt communally, some winter roosts may reach upwards of 200 individuals. They may also share roosts with long-eared owls (Asio otus). These owls are also strongly associated with northern harriers, because they both require the same food items. Pair bonding and courtship displays being in February. Male owls perform a sky dancing display, complete with song, aerial acrobatics, including wing-claps and talon grappling.

History - Historically, short-eared owls were a common bird of New Jersey. They bred along the Atlantic and Delaware Bay coasts and in the early 1900ís Elizabeth, NJ supported numerous short-eared owls nests in the townís salt marshes. New Jersey also provided winter roosts for the short ears. During the winter of 1878-79, a roost in Princeton hosted nearly 200 owls. Slowly, short-eared owl numbers declined. Shooting and egg collection initiated the decline, but eventually habitat loss impacted the species the greatest. After World War II, the coastal marshes were filled and by the 1950ís the breeding population of short-eared owls had declined greatly in the Northeast. In 1979, habitat loss and population declines led to listing the bird as a threatened species in New Jersey. And, in 1984 the breeding population of short-eared owls was listed as endangered. The last confirmed nesting in New Jersey was in 1979. Worldwide, this birdís population is considered secure. However in the Northeast, it is listed as endangered, threatened and of special concern in multiple states that were part of their historical range. (Information from NJDEP Division of Fish and Wildlife)

Owls at the Pole Farm - Short-eared owls were first spotted wintering at Mercer County Park Northwest in 2006. Typically, they arrive sometime in January (sometimes December) and occupy the fields adjacent to Federal City Road until March. The birds generally become active 15 minutes prior to sunset, and spend their time flying low over the fields scanning for a meal. If northern harriers are still active, there may be some quarreling and chasing between the two birds. Otherwise, they spend the day roosting in tufts of grass in the field. Occasionally, one hears the (bark/cluck) of the short-ears but usually their hunting is performed in silence.

Because the short-ears fly over the driveway, observers are asked to park their vehicles in the first parking lot along the driveway, near the barns. Birders need not travel far to watch the short-eared owl spectacle, for the driveway is a prime viewing spot. Also, because of their sensitivity to humans, please remain on the driveway and other County-approved trails. Walking into the fields to take a better photograph or get a better view is very inappropriate.

During the 2008-2009 winter season, the Pole Farm hosted approximately half a dozen short-eared owls and 15 northern harriers. This park may not see that many short-eared owls annually, because they fluctuate with their food resources, however it is an excellent wintering ground for the birds and it is managed as such a habitat. Managing the Pole Farm as a high-quality grassland requires an agreement between the Park Commission and the users of this park. The Park Commission follows a mowing schedule created by USDA- NRCS to keep the grassland a prime habitat. However, park visitors must do their part and abide by regulations set by the Park Commission to keep the common and rare wildlife in the grasslands. These regulations include staying on the trail and keeping all dogs on a leash.

 

 

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Last revision: Sunday, February 21, 2010