Otay Water District Rehabilitates Burrowing Owl Habitat to Conserve and Protect Owls and Their Environment

Burrowing owl

Otay Water District Rehabilitates Burrowing Owl Habitat to Conserve and Protect Owls and Their Environment

11:43 02 June in News

The Otay Water District owns the 240-acre San Miguel Habitat Management Area (HMA) reserve and mitigation bank, located in eastern Chula Vista. A 10-acre portion of the HMA is a dedicated native grasslands area that contains artificial burrowing owl burrows. Burrowing owls are threatened by land development and intense agriculture and are designated as “Species of Special Concern” by the California Department of Fish & Wildlife (CDFW). The owls also are protected under the Federal Migratory Bird Treaty Act.

Burrowing owl burrow

Setting box for retrofitted burrow.

In 2019, the District, with CDFW’s guidance, began planning for the retrofit of existing artificial burrows and installation of several new burrows with the most current burrow design, intending to allow for maximized breeding success for the burrowing owl in the District’s HMA. A secondary goal is to enhance the value of the native grassland habitat by removing invasive plants that surround most of the artificial burrows.

Burrowing owls are small owls with bright yellow eyes, a brown head, wings with white spotting, and prominent white eyebrows. They measure 7 to 11 inches long, with wingspans of 20 to 24 inches, and weigh 5 to 9 ounces. Their diet consists primarily of insects, small rodents, amphibian and reptile species, other birds, and carrion.

Burrowing owl

Burrowing owl

Burrowing owls occupy grasslands and scrub, as well as other open sites such as agricultural lands, old fields, and other open developed areas. Their nesting habitat consists of open spaces with mammal burrows, but they will also nest in shallow, underground, human-made structures.

“The District’s project to enhance the existing burrowing owl habitat is so important because the HMA is a protected area where the owls can safely live and breed,” said Otay Environmental Compliance Specialist Lisa Coburn-Boyd. “Increasingly, in San Diego County, the burrowing owl population is declining because of habitat loss and fragmentation.”

Originally, the District constructed fifteen artificial burrows at its HMA as mitigation for impacts to burrowing owl burrows due to the construction of the District’s 711-3 reservoir and the creation of a golf course (former Salt Creek Golf Course). Since 2003, the District has maintained and monitored an old design of the artificial burrows and their native grasslands habitat. Although the HMA had regular burrowing owl visitors during that time, the breeding success was limited with no owl breeding pairs.

Burrowing owl

Burrowing owl at old burrow consisting of outdated design.

Beginning in 2020, the District used the updated burrow design recommended by the CDFW and developed by the San Diego Zoo Institute for Conservation Research. The District retrofitted and enhanced five existing burrows and installed six new burrows. During construction of the burrows in January and February, two burrowing owls were observed and “seemed” to be overseeing the construction. Unfortunately, they did not breed this year, but the District hopes they will be back to move into the new burrows now that they are completed.

LIVE WEBCAM OF BURROWING OWLS AT DISTRICT’S HMA
Check out the burrowing owl live webcam at the District’s HMA here: sdzsafaripark.org/cams/burrowing-owl-cams (courtesy of the San Diego Zoo).