Results from our 2025 roadkill surveys

Check out our 2025 roadkill survey report! We learned a lot and are looking forward to sharing our findings.

From April – November 2025, CSDP volunteers conducted road-cruise surveys on four routes to learn more about roadkill, wildlife-vehicle collisions, and wildlife movement across roadways. Researching roadkill helps inform our recommendations for future connectivity and wildlife crossing projects.

Read the full report here

Key takeaways

  • We made around 340 total observations during the surveys.
  • 32% were dead animals (112), and the rest were alive animals seen on the roadway.
  • We saw a lot of seasonal trends — including two waves of baby snakes and a seasonal spike in Carolina wolf spiders. We saw 70% of animals during monsoon season, as expected.
  • We saw the least roadkill, and wildlife overall, on the most rural route.

What roadkill we did see is a mere fraction of what is actually killed: the majority of roadkilled animals
are quickly removed from the road by other species, including humans. As one study of roadkill in
Saguaro National Park noted, “animals killed by vehicles may be difficult to observe, particularly during
driving surveys, and carcasses may not persist between surveys due to scavenging and other factors.”1

What’s next?

In 2026, we are running a new survey season with two transects: Mile Wide Road, and the frontage road next to the Santa Cruz River Wildlife Ramp.

This is just a start – with a larger dataset, we could start to identify hotspots and areas in need of better crossing solutions. We’ll need to conduct more surveys and combine our data with past surveys to do that!

We look forward to sharing what we learn!

A Couch’s spadefoot toad, alive on the road.

Acknowledgements

Thank you, Dr. Brian Blais — your guidance and expertise was invaluable.

Thank you to our survey volunteers: Erik Donkersley, Rachel and Craig Ivanyi, Keith Kleber, Jane “Middy” Henke, Kate Hotten, Kayla Lauger, Jessica Moreno, Katie Rodriguez, and Virgil Swadley.

And a big thank you to the Santa Cruz Valley National Heritage Area for funding this report!

1Gerow, Kenneth; Kline, Natasha C.; Swann, Don E.; and Pokorny, Marin (2010) “Estimating Annual Vertebrate
Mortality on Roads at Saguaro National Park, Arizona,” Human–Wildlife Interactions: Vol. 4: Iss. 2, Article 15.
DOI: https://doi.org/10.26077/dhg5-wg98

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