raptor Rapture!

Article by Melanie Campbell-Carter and Mike Shaw
Photos by Mike Shaw and Melanie Campbell-Carter

American Kestrel in flight

Scientific organizations across the country have joined in studying American Kestrel populations and how they are affected by human activity. The marked decline in Kestrel populations has been under investigation for over a decade by Hawkwatch International (HWI), and our RillitoBend neighbor and Board advisor Mike Shaw has been on the job for Hawkwatch for fifteen years. 

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When the pandemic somewhat stranded Mike in the Tucson area, he kept working by expanding the study area to Southeast Arizona as it was a logical addition to HWI’s mid continent study site in Utah and a smaller satellite study in northern Idaho. He now has 75 nest boxes in Southeast Arizona – and one of the first things he learned was that the boxes around Tucson were far more popular with Western Screech-Owls than Kestrels. The numbers were almost reversed from their two northern sites where Kestrels far outnumber Screech-Owl occupants. However, the boxes outside of Tucson, such as the ones in Sonoita (think cooler temps), get heavy Kestrel usage with only an occasional Screech-Owl. 

American Kestrel with prey

It makes sense: desert heat is rather unfriendly to diurnal, or daytime, raptors. It is too hot for their prey to be out running around, and it is too hot to chase them. Nocturnal hunters such as owls have the advantage of working the night shift at the same time mice and small mammals are most active and available. 

Nest box in RillitoBend mesquite tree

Despite the initial project being designed to study Kestrels, large numbers of Screech-Owls using the Arizona boxes is welcomed by HWI. They’ve been researching small, cavity nesting owls since 2016 in the Chiricahua Mountains southeast of Tucson and the urban/wilderness datasets  are great compliments to each other. In fact, HWI’s Kestrel specific study has been enlarged to include all cavity nesting raptors.  

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Kestrel chick on scale

The first nest box placed in a City of Tucson park was hung in Rio Vista Natural Resource Park. Now at least seven city and county parks have nest boxes and RillitoBend is home to over a dozen boxes scattered throughout the neighborhood. During the February-May nesting season, boxes need to be monitored every 7-10 days and available eyeballs are a critical component of the effort.

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Adult screech-owl in good hands!

Mike would be delighted to have you join the other volunteer Community Scientists who monitor boxes in and around Tucson. Hawkwatch will train you how to do it and how to submit the data. They also welcome participation from landowners who have installed a box on their property and are willing to submit data over the same time period. For more details, you can email Mike at mshaw@hawkwatch.org.

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For more information about Hawkwatch International, please see their website, Hawkwatch.org. There are several ways to support their research, and Mike (mshaw@hawkwatch.org) welcomes your questions and your support.