Wildlife Results: It Works!
Since the Oracle Road wildlife crossing were finished in March 2016, the Arizona Game and Fish Department has been monitoring the crossings for wildlife use and conducting regular roadkill surveys along this stretch of Oracle Road.
The most recent report from Arizona Game and Fish Department’s monitoring results can be found HERE.
Now that the Oracle Road wildlife crossings are finished, a 4-year monitoring program is underway to document all the wildlife using these crossings. Arizona Game and Fish Department (AGFD) is spearheading the program, with collaboration from the Coalition and our volunteer-driven Wildlife Camera Monitoring Program.
In April 2016, the AGFD installed 8 video cameras and 4 still cameras (all motion-activated) on the new Oracle Road wildlife bridge. They also installed 4 still cameras on the wildlife underpass. AGFD will also be conducting roadkill surveys, monitoring the movements of Sonoran Desert tortoises and mule deer in the area of the crossings, and providing recommendations for the adaptive management of the structures.
According to the April 2020 monitoring report from AGFD:
Image data has been analyzed from project inception (April 18th, 2016) to April 8, 2020. A total of 26 native vertebrate species have been documented at the crossing structures, 11 at the overpass, and 25 at the underpass. Of these, 20 of these species have been documented crossing SR77 at the structures, 11 at the overpass, and 20 at the underpass. 10,843 wildlife crossings have been documented across both structures, with 5,490 and 5,353 at the overpass and underpass respectively. Mule deer, coyote, and javelina utilize the overpass most regularly with 4,338, 453, and 598 crossings respectively. At the underpass javelina, coyote, and mule deer are again the most regularly documented species with 2,259, 1,765, and 1,109 crossings respectively. Along with bobcat, these species account for over 98% of documented crossings at each structure. Species of note observed crossing through the underpass include a white-nosed coati in September 2017 and a white-tailed deer in January 2019.
Total wildlife crossings at each structure have increased year on year since project inception. Crossings by mule deer, javelina and bobcat at the overpass have increased each year, while coyote use remained at a similar level through the initial three years of monitoring before dropping in year 4. Crossings by coyote and mule deer at the underpass have increased each year, while use by javelina and bobcat increased through the first three years of monitoring then dropped in year 4.
Road mortality surveys were completed in August 2018, 14 survey cycles have been completed in total, 7 each in 2017 and 2018 respectively. Each year four survey cycles were completed during the first four weeks of May; the remaining three survey cycles were completed during the first three weeks of August. All collected road mortality data has been compiled. 1,849 observations were recorded over the course of the project, of these 1,799 related to vertebrate mortalities, representing at least 80 species. Merriam’s kangaroo rat, couch’s spadefoot, and regal horned lizard were the most commonly recorded species with 257, 187, and 143 records respectively. Notable records include; Sonoran desert tortoise, gila monster, bobcat, javelina, black-necked gartersnake, checkered gartersnake, barn owl, and kit fox.
The status of installed wildlife fencing along the surveyed extent of SR77 allows us to compare the effectiveness of wildlife fencing in several configurations with respect to the ROW. There is evidence to suggest that installed wildlife fencing is proving effective throughout the surveyed extent. A single ungulate mortality has been recorded and very few carnivores were detected within the ROW. Overall, vertebrate mortality hotspots were most significant where ROW 17 fencing directly fronted the highway on one side but was retracted or absent on the opposing side. This was most pronounced between mile markers 82 and 83 where land adjacent to the unfenced frontage is less developed. Equally, the most significant vertebrate mortality cold spots were detected where development adjacent to the ROW was heavier and/or where ROW fencing was in situ along both frontages.
The installed wildlife fencing is designed to exclude all but wildlife except for birds and climbing rodents. Wildlife fencing currently exists on BOTH sides of Oracle Road between mileposts 84 and 86, but only on the EAST side of the road between mileposts 82 and 84, which is likely why we are seeing a roadkill hotspot appearing there. We are working with our partners and nearby homeowners to close these gaps in the wildlife fence.
AGFD’s complete 4-year monitoring plan can be found here. If you are interested in more data, maps, tables, and photos of wildlife using the Oracle Road wildlife crossings, please check out the latest monitoring report HERE. Also, scroll to the second half of this AGFD PowerPoint Presentation to see even more data.
Articles in the News & Updates section of our website with more information about monitoring results from the Oracle Road wildlife crossings can be found below:
The latest monitoring data from the Oracle Road wildlife crossings! – April 22, 2020
Oracle Road wildlife crossings featured on FOX10 Drone Zone segment – December 17, 2019
New interactive case study about the Oracle Road wildlife crossings – December 7, 2018
In the News: Oracle Road wildlife crossing results make a splash! – March 16, 2017
The first year of results are in! – March 13, 2017
Video footage of animals using the wildlife bridge. All video footage and still photos courtesy Arizona Game and Fish Department.
Still photos of wildlife using both the wildlife bridge and wildlife underpass (click on arrows below each photo to scroll through slideshow)
A mule deer exits the west entrance of the Oracle Road wildlife underpass in April 2016.
WILDLIFE CAMERA MONITORING PROJECT
The Coalition’s own wildlife camera monitoring project will supplement these studies, by revealing the number and type of species that are moving in the area that could potentially use the wildlife crossings. For instance, our cameras captured one photograph of a white-nose coati approaching the underpass from the east, but AGFD’s cameras did not record it using the underpass. This information is useful to help biologists determine if any changes or modifications should be made to improve the effectiveness of the structures for certain species.
Learn more about our camera monitoring project, and see the photos, HERE.
HELP US GATHER MORE DATA!
We need your eyes, too. Please report wildlife sightings on Oracle Road (alive or dead), and in the surrounding area in Rancho Vistoso, Sun City, and other nearby neighborhoods, bike paths, and trails. Share what you see on: http://www.inaturalist.org/projects/csdp-safe-passages