PIMA COUNTY, AZ (Tucson News Now) - Western burrowing owls are making a return to the Santa Cruz River, thanks in part to a little help from the Pima County Flood Control District.
In 2013, while working on the Paseo de las Iglesias Santa Cruz River Bank Protection Project, crews discovered two owls living on the east bank of the river. To avoid harming the birds Flood Control called in experts to relocate the pair to a sanctuary in Cave Creek.
Since work on the Paseo de las Iglesias has finished, eight of the owls have been returned to the area.
Work began in February to reconstruct burrows the owls use. As the owls don't dig their own burrows, they rely on abandoned ones of mammals like prairie dogs, badgers, coyotes, and even foxes. Volunteers from Flood Control, Wild at Heart, the Tucson Audubon Society and Tucson Electric Power built 16 new burrows using plastic buckets, tubing, and PVC pipes to mimic natural burrows. These burrows were then covered in rock to provide additional protection to the habitat entrances.
"Artificial burrows are designed to provide a bridge for owls in areas that lack sufficient numbers of burrowing mammals, said Greg Clark, Wild at Heart Burrowing Owl Habitat Coordinator. "These should last about 20 years which should give ground dwelling mammals time to recover and start building new natural habitats."
Work on the $14 million Paseo de las Iglesias wrapped up in April 2015. The award-winning project used innovative design and engineering techniques such as discontinuous bank protection, the reuse of rubble concrete for decorative walls and to create wildlife habitat as well as an extensive use of rain water harvesting and all-native plant landscaping. Funding came from bonds approved by voters in 2004.
Those eight birds were brought into the new habitat back in April. A permeable tent was put over the birds to give them time to acclimate to the area and each other. The tent allowed air and water in and provided shade while keeping out potential predators or curious people. The birds were fed defrosted frozen mice from another team of volunteers coordinated by Paseo de las Iglesias Project Manager Deirdre Brosnihan during this adjustment period.
"One of the most rewarding parts of my work on Paseo de las Iglesias has been helping return the owls to the habitat we built," Brosnihan said. "As an engineer by training, it has been extremely interesting to see how the owls have specially adapted to nest underground. I've also enjoyed learning about the biology of these birds and their important place in our ecosystem."
The Western burrowing owl is on the decline in the region and is one of 55 species covered in Pima County's Sonoran Desert Conservation Plan. It is also included on the county's Multi-species Conservation Plan, which was finalized in 2016 and provides protective measures for the burrowing owl and 33 other species.
"The district's work at Paseo de las Iglesias embodies the spirit of the SDCP and the specific, measurable protective mechanisms of the MSCP," said Brian Powell, Program Coordinator with the county's Office of Sustainability and Conservation, which is responsible for implementation of the MSCP.
The burrowing owl is protected under federal law. Signs posted at the location by The Arizona Department of Game and Fish request that the public not disturb the birds. Violators could face fines or jail time.