How Cutting Down Trees Helps a Unique Owl in Utah

At Audubon’s Gillmor Sanctuary at Great Salt Lake in Utah, the grass and scattered shrubs of the uplands serve as ideal habitat for Burrowing Owls. 

While most owls are tree dwellers, this ground-dwelling species prefers open, treeless landscapes with short, sparse vegetation. It’s no coincidence that these habitats also support the species who dig the burrows the owls nest in. In the western United States, this includes ground squirrels, prairie dogs, badgers, and desert tortoises.

Like many grassland species, Burrowing Owl populations have declined throughout their range due to habitat loss, human-wildlife conflict, and other factors. Due to downward population trends, Burrowing Owls are listed as endangered in Canada and as a Species of Greatest Conservation Need in each U.S. state they reside in. 

At Gillmor Sanctuary, Audubon is addressing local population declines and improving conditions for Burrowing Owls and other wildlife by restoring native habitat.

Taking On Tamarisk

One of the primary focuses of the restoration work has been removing invasive tamarisk trees. Tamarisk, native to Eurasia, was introduced in the 1800’s and used in bank stabilization, but it has since spread vastly in riparian corridors and uplands with high water tables. As a result, areas of Gillmor Sanctuary that were once open grassland and shrubland transformed into dense, forested environments—and many grassland birds, mammals, and other wildlife dispersed from the area. 

So far, Audubon has cleared over 1,000 acres of tamarisk from Gillmor’s uplands and the uplands of neighboring properties. Many of these areas have also been seeded with native grasses, shrubs, and forbs. These efforts have restored the habitat back to low, open landscapes and increased the abundance of native vegetation that Burrowing Owls, their prey, and other native wildlife depend on.

Surveys conducted before, during, and after restoration have helped gauge the response of grassland birds. With the tamarisk trees gone, Burrowing Owls—as well as Long-billed Curlews and Willets—are once again nesting in the uplands. Additionally, sightings of grassland songbirds such as Horned Larks and Savannah Sparrows have increased.  Grassland mammals are also returning to these reopened areas, including pronghorn and jackrabbits. 

Tamarisk trees still cover significant surrounding areas, creating opportunities to collaborate across property boundaries and interests. Looking ahead, we hope to expand tamarisk removal efforts along Great Salt Lake in partnership with duck clubs, the Salt Lake City airport, ranchers, and other landowners. 

Restoration efforts on Gillmor Sanctuary’s uplands also go beyond tamarisk. Learn how Audubon is encouraging more Burrowing Owls to nest at the sanctuary with new digs—literally! Read more.

We would like to extend a huge thank you to all of the organizations and volunteers who made this work possible. Thank you, also, to the National Fish and Wildlife Federations’ America the Beautiful Challenge Grant and Browning Foundation for funding this important work.