by Rob Hallagan


Yes, there are amphibians (toads) in Scottsdale’s McDowell Sonoran Preserve. Hidden. Buried in the Earth. Waiting for the rain.

Stewards working under McDowell Sonoran Conservancy’s Citizen Science Program with the Parsons Field Institute have been conducting amphibian surveys over several years. The purpose is to systematically monitor amphibian abundance at a seasonal water source during the monsoon season, when amphibians are most active. We also document any other species we may find at the tank that evening. There is a healthy population of small mammals, birds, reptiles, and arthropods. We have documented tarantulas, wolf spiders (hundreds), black widows, camel spiders, diamondback rattlesnakes, California kingsnakes, coyotes, desert cottontails, rock squirrels, bats, elf owls, great horned owls, lesser nighthawks, mallards, packrats, and kangaroo rats. Even a seasonal water source supports an extremely broad ecosystem.

Also, hidden in the earth here are fairy shrimp and triops. These crustaceans explode from the dirt bed when standing water is present. Their cysts/eggs can be dormant in the soil for decades until awakened by fresh water. There are swarms, millions. The triops are carnivores and cannibals. First, they eat the fairy shrimp, then turn on their own kind. So, the next time you’re zipping along the 101 after a hard rain, look over; there’s a life-and-death struggle going on beneath the surface in those retention ponds.

This survey is one of the very rare nighttime events authorized in the Preserve. Because it is conducted after closing hours and with vertebrate species, special City of Scottsdale as well as Arizona Game and Fish Department Permits are required. We monitor most Monday and Thursday nights July through September.

Based on the current COVID-19 situation, this year the Survey Leads made a difficult decision not to open this activity to other Stewards through the month of September. In all past years, and hopefully resuming again next year, a survey team is comprised of one lead and up to two other Stewards interested in learning about toads and contributing to the Citizen Science Program. For me, that is exactly how I became involved, and now I am working as a lead this year. I was looking for a summer activity for the dog days of August – this fit the bill: tolerable temperatures; good conversation; beautiful sunsets; and fantastic mentoring by Stewards Sue Handke, Debbie Langenfield, Karen Hajek, and Leona Weinstein. On a rare night, you can even spot Parsons Field Institute Manager Tiffany Sprague.

Coming from a background in the Physical Sciences, for me this has been an excellent introduction into the Life Sciences and good adjunct to other Citizen Science projects as well as events Guided Hike and Bike offers: bird walks, arthropod educational walks, Sensing the Desert hikes (and I’m going to add Nature as Therapy, too).

Amphibian species that we have documented so far:

  • Red-spotted toad
  • Couch’s spadefoot
  • Sonoran Desert toad
  • Great Plains toad

Other species on the “Most Wanted” list we are hoping to document:

  • Woodhouse’s toad
  • Mexican spadefoot

We document calls, sightings, and try to get photo vouchers. Beginning this year, we are recording observations using ArcGIS Survey123 (the same mobile phone app used by the Patrol Program and similar to the one used for the invasive plant surveys). It replaces a paper-based data sheet and quickly aggregates weather, location, and species data for study.

As I write this post, we are still in our excessive heat “Sad-soon” following last year’s “Non-soon,” but when the rain comes, amazing life emerges from the ground. We all honestly look forward to re-opening the program post-COVID and bringing this opportunity back to the general Steward population.

Photo credits: Rob Hallagan, Leona Weinstein, Karen Hajek, Debbie Langenfield, Sue Handke