ORO VALLEY – Mule deer like to go over the road, javelina and bobcats like to go under it, and coyotes are cool with either method.
Those are the
initial results of a survey of wildlife crossings of State Route 77, also known as Oracle Road, after a $9.5 million wildlife crossing opened last year near Oro Valley.
Between April 2016 and January 2017, 1,182 animals have been documented using the SR 77 overpass and underpass. Deer are the heaviest users, with 565 total crossings, some even crossing over rush hour traffic. Coyotes have crossed 303 times, javelina 250 and bobcats 57. The deer prefer to use the overpass with only 20 deer choosing to scoot through the underpass. Javelina and bobcats have the reverse opinion about how to cross a road, with only eight and four, respectively, electing to take the overpass. Coyotes lean toward the underpass, with 191 crossings, but don’t mind the overpass either, crossing it 112 times.
The numbers were part of an Arizona Game and Fish Department progress report presented to the Pima County Regional Transportation Authority in February. It was the initial report of a four-year study to evaluate measures to reduce wildlife vehicle collisions and promote wildlife connectivity between the Santa Catalina and Tortolita mountains.
The overpass project is part of a $2.1 billion Regional Transportation Authority transportation and transit improvement plan approved by Pima County voters in 2006. The Arizona Department of Transportation was the lead agency on the project as part of its partnership with the RTA in widening Oracle Road/SR 77 from Oro Valley north to the Pinal County line.
Maintaining connectivity between sky islands and along riparian habitats are important components of Pima County’s Sonoran Desert Conservation Plan and the Oracle Road/State Route 77 connection between the town of Oro Valley and the community of Catalina is identified in the plan as one of six key wildlife linkages in the county. The county was among the many groups that advocated for the wildlife overpass near Catalina in the RTA plan and acquired property on either side of the wildlife crossing to prevent encroachment and keep the pass open to wildlife.
According to the report: “There is growing interest in excluding wildlife from roadways for safety reasons, in addition to maintaining landscape connectivity for wildlife populations. This concern has generated an interest in safe crossing structures for wildlife by both transportation and resource management agencies as a tool for mitigating the negative interactions between roadways and wildlife.”
Game and Fish and a coalition of collaborating agencies will study the number of crossings for four years as well as the number of animals killed trying to cross a six-mile stretch of Oracle Road/SR 77 that borders either side of the wildlife crossings. The roadkill surveys will occur at various times during the study period.
Crossings of the overpass and underpass are tracked via wildlife cameras that trip when animals pass in front of them. A team of volunteers monitors the cameras and downloads the images.
One surprising finding was the number of people using the crossings. The cameras documented 220 human crossings during the first 10 months of the study.
“Human activity discourages wildlife use of these important crossings” said Pima Association of Governments Deputy Director Jim DeGrood. PAG manages the RTA. “People can unintentionally scare off wildlife by their presence or sign, so we ask the public not to approach these crossings.”
ADOT, the Coalition for Sonoran Desert Protection, the Sky Island Alliance and the Tucson Audubon Society are assisting Game and Fish in the study.
For more information of analysis, contact Jeff Gagnon, Wildlife Specialist at the Arizona Game and Fish Department. He can be reached by phone at (928) 814-8925 or
email.
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