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MARK BROWNING

Wisconsin Barn Owls

Barn Owls in Wisconsin

Barn_Owl_Flying_8349The barn owl in Wisconsin is rare and listed as endangered. Most breeding records have come from the southern counties where the state Bureau of Endangered Resources has attempted to bolster barn owl populations over the years by installing over one hundred nest boxes and releasing captive bred owls. The Wisconsin Department of Natural Resources in recent years has also installed a number of nest boxes.

Although natural grasslands and wetlands have declined in the state and been replaced by row crops such as soy, there are plenty of pastures and meadows remaining throughout the state. A main limiting factor is the severe winters, particularly the heavy snowfalls that regularly occur, making it difficult if not impossible for barn owls to catch prey beneath the snow. Mild winters allow barn owl populations to grow, but a single heavy snowfall that lasts over a week on the ground can severely set back barn owl numbers.

The state of Wisconsin conducted captive breeding program and released 98 young birds into the wild between 1982 and 1987. This program was discontinued since there was no apparent increase in barn owls in the wild. This is typical of such barn owl breed and release programs – due to dramatic dispersal of young in the fall, high mortality, and low returns to natal areas, barn owls are not a suitable species for breed and release. Habitat enhancement, such as nest box programs, have proven to be far more effective.

 

Wisconsin Barn Owl Breeding Records

Wisconsin Barn Owl Breeding Records

Nonetheless, barn owls do breed each year in the state and nest box programs have had some success. The range map is from the Natural Heritage Inventory Base in 2012 and shows counties of confirmed nesting. Keep in mind that such records are dependent on field work which is often limited and that barn owls can be very difficult to detect since they are secretive and nocturnal. Chances are that there are more barn owls than found and that other counties may harbor them. Residents in these or neighboring counties who live in good habitat such as grasslands, wetlands, hayfields, or pasture would be helping conservation efforts by installing nest boxes and contacting their local DNR office when barn owls are seen.

 

Wisconsin grasslands

Wisconsin grasslands

Barn owls in Wisconsin feed mainly on voles (meadow mice) and shrews. They nest in silos, barns, outbuildings, tree cavities, and nest boxes. They breed March through July, laying three to nine eggs, with four or five on average. Researchers believe that most Wisconsin barn owls leave for the winter, but there are records of overwintering as well. It may be the young that disperse in the fall, and the adults that stay, as in many other states.

 

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MARK BROWNING

Barn Owls in Washington

Washington Barn Owls

barn-owl

Barn owls are numerous in most areas of Washington

Barn owls are common in the state of Washington along the entire extension of Puget Sound, along the coast, in the numerous agricultural valleys on both sides of the Cascades, and in the southeastern half of the state. Barn owls are not found to any degree in the Cascades, nor the forested northern mountain counties, but wherever there is agriculture barn owls are found in good numbers. Barn owls even move into large clear cuts where the forest has been cut for lumber.

The river systems, including the Snake and Columbia Rivers, contain good populations that frequently nest in the nearby volcanic cliffs of basalt and lava where vertical cracks and potholes afford excellent nesting sites. In the Palouse Country, where vast quantities of wheat and hay are grown, they are common as well. Here they nest in barns and haystacks. Rehabbers frequently have to bring in nestlings that have been exposed when the hay bales are put on trucks for shipping.

The author once spent a summer harvesting wheat in the Palouse Country. Once the combines passed over the wheat, the farm dogs chowed down on the voles and gophers that were suddenly exposed—and those dogs could barely hold their stomachs off the ground after a day’s eating. This very high number of rodents could support equally surprising numbers of barn owls if enough nest boxes were installed.

Washington Agriculture and Barn Owls

BARN_OWL_ORCHARD_550

Orchards attract large numbers of voles, barn owls’ favorite prey.

With almost 40,000 farms comprising 15 million acres, Washington is a major agricultural region. It is first in the nation in growing apples, cherries, pears, and raspberries, and second in the nation in grapes. Orchards and vineyards both attract high numbers of the barn owl’s favorite prey, voles and pocket gophers.

Apple, cherry, and pear orchards are often damaged by voles when these rodents chew on the bark and roots of the trees.

Washington Vineyards and Barn Owls

Washington is second only to California in amounts of grapes harvested. The state grows grapes in all of its agricultural valleys. Many of the regions wine growers use barn owls for natural rodent control and their use is rapidly increasing. Major wine growing regions include the Seattle-Puget Sound Region, Walla Walla Valley, Cascade Valley, Yakima Valley, Pullman-Spokane, Tri-Cities, and the Vancouver-Columbia Gorge. The climates of all of these areas are unique and each produces different qualities in its wines.

Using Barn Owls for Natural Rodent Control in Washington

Nest boxes surrounding Vino Farms

A vineyard surrounded by nest boxes

With the high numbers of barn owls in the state, nest boxes should receive quick and high occupancy. Just as in California, Washington vintners and orchardists can easily attract large numbers of these rodent-eating raptors to their farms, reduce their use of poisons and the labor involved in trapping, and see less damage to their crops, soil, and irrigation systems.

For more information, go to our Product Page, read about barn owls and Integrated Pest Management, and our excellent article on the Economic Value of Barn Owls.

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