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  • Flood Control restores burrowing owl habitat in Paseo de las Iglesias area

    May 26, 2017 | Read More News
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    Western burrowing owls once again roam free along a stretch of the Santa Cruz River as part of the Pima County Flood Control District’s commitment to environmental stewardship. Eight of the raptors were released May 27 from a temporary enclosure where they had been kept since late April.

    Survey teams working on the Paseo de las Iglesias Santa Cruz River Bank Protection Project discovered two owls living on the east bank of the river before construction began between Ajo Way and Silverlake Road in November 2013. To avoid potential harm to the birds during construction, Flood Control called in experts with the group Wild at Heart to relocate the pair to a sanctuary in Cave Creek.
    Burrowing owl
    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 rainwater harvesting and all-native plant landscaping. Funding came from bonds approved by voters in 2004.

    In February of this year, volunteers from Flood Control, Wild at Heart, the Tucson Audubon Society and Tucson Electric Power worked to build a new series of 16 burrows using plastic buckets, plastic tubing, and PVC pipes to mimic the type of dwelling the owls prefer, then buried them and covered the habitats' entrances with stones to provide additional protection. Western burrowing owls do not dig their own burrows. Instead, they rely on the abandoned burrows of mammals such as prairie dogs, badgers, coyotes, and foxes.

    “Artificial burrows are designed to provide a bridge for owls in areas that lack sufficient numbers of burrowing mammals," said Greg Clark, Owl burrowWild 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.”

    In April, Clark introduced eight of the birds to the site. Volunteers built a permeable tent over the burrow to give the birds time to acclimate to their new surroundings and each other, allowing air and water in and provide shade while keeping out potential predators or curious people. They received regular feedings of 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.”

    Concern over the species’ decline in our region led to the burrowing owl being one of 55 species covered in the county’s award-winning Sonoran Desert Conservation Plan (SDCP.) More recently, the species was included in the county’s Multi-species Conservation Plan(MSCP), 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.

    UPDATE: an inspection of the burrows following the owls' release found the birds had laid between eight and 12 eggs during their acclimation period.

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