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Constructing Habitat for an Industrious Owl

The Corps’ efforts to bolster the burrowing owl population in Eastern Washington

Walla Walla District, U.S. Army Corps of Engineers
Published Aug. 13, 2020

 

For most bird species, the concept of living underground would be considered strange. For the burrowing owl, living anywhere else would be unthinkable.

Burrowing owls are native to the region in Washington now known as the Tri-Cities. However, human development in the area has fragmented their habitat and made it harder for them to survive.

To combat this, the U.S. Army Corps of Engineers (Corps), Walla Walla District, has been constructing artificial burrow systems for burrowing owls in the Habitat Management Units (HMUs) surrounding Ice Harbor Dam.

These burrows consist of 10-foot tunnels, made from PVC pipe about 6-8 inches in diameter, and a burrow chamber made from plastic fruit barrels that have been cut in half. A wire mesh floor is put on the burrow chamber to allow for water drainage and to keep predators for digging into where the owls are nesting.

“The burrowing owl is important because they’re the ecosystem engineer for a lot of habitats in this area,” Jim Castle, Wildlife Biologist of the Corps Walla Walla district, said.

Once constructed, the artificial burrows are buried in the ground. The nesting chamber is topped by a “lid” made from a weighted bucket. This bucket can be lifted off the burrow to allow researchers to look down into the nest and check on the owls if necessary.

Burrowing owls are known to readily adopt artificial burrow systems, which is no surprise since they commonly take over burrow systems created by ground squirrels. These owls are not ambitious diggers, especially in firmly packed soil. More often they will find an existing structure, be it a ground squirrel tunnel, an irrigation channel or a pile of rocks, and improve it to suit their living needs.

Male burrowing owls often find a raised place to perch in to guard their territory against predators and other burrowing owls. To accommodate this, the Corps places a t-stake near burrow entrances to provide a place for a male burrowing owl to sit.

The Corps installed 16 burrows about three years ago. So far, no burrowing owls have taken up residence.

“This area is still inhabited by burrowing owls, in different part of the Tri-Cities, in pockets,” Castle said. “We’re hoping to improve some of the habitat by installing these artificial systems so that if there’s an opportunity for them to re-establish in this area, they’ll have a place to go to. It’s sort of like building them an apartment complex.”

According to the Cornell Lab of Ornithology, burrowing owls are small, between seven and 10 inches long with long legs. They can be found in regions of the Western United States, through Mexico and down to the Southern tip of South America.

This effort to help the region’s burrowing owls is part of the Corps’ goal to increase biodiversity by creating habitat appropriate for all species from mammals and reptiles, to amphibians and insects; from the birds that live in trees, to those that choose to make their homes under the ground.