CHS Blog

Adventures in Canadian Herpetology: Recounting a Decade of CHS Field Trips

Part 1: Grasslands National Park, 2009

June 22, 2020
Joe Crowley, SAR Specialist with the Ontario Ministry of the Environment, Conservation and Parks

Each fall, herpetologists from across the country converge for the annual Canadian Herpetological Society conference, which has become an invaluable forum for us to share our work, meet new people and catch up with old friends. The Monday field trip, which follows the weekend’s formal conference program of platform and poster presentations, is also a source of anticipation and excitement for many of us—an excuse to don our field gear and spend a day with friends and colleagues in search of amphibians and reptiles. With the conference being held in a different location each year, the field trip provides an exciting opportunity to explore different ecosystems across Canada, learn about local research and conservation initiatives, and encounter a diversity of the amphibian and reptile species that occur from coast to coast. I have been fortunate to be able to attend every CHS conference and field trip since 2009, so I thought it would be fun to write a short series for The Drift Fence that revisits some of these fond memories.

Although the annual conference has been running in one form or another for over 30 years, I am starting this series with our adventures in Grasslands National Park, following the September 2009 conference in Saskatoon. At that time, the Canadian herpetology conferences were run as joint meetings of the Canadian Amphibian and Reptile and Conservation Network (CARCNET) and the Canadian Association of Herpetologists (CAH), which merged in 2013 to form CHS.

Grasslands National Park (top) and 2009 CHS field trip participants (bottom)

Owing to the considerable travel distance between Saskatoon and Grasslands National Park—a 4-hour-plus drive—the field trip was held over two days with an overnight stay in the nearby town of Val Marie, making it particularly memorable as the only two-day CHS field trip in recent history. On the first day, we were up and on the road especially early (by herpetological standards) to facilitate a late morning arrival in Grasslands National Park. Andrew Didiuk, our field trip leader and a wildlife biologist with the Canadian Wildlife Service, explained the plan for the day and discussed rattlesnake safety, after which we eagerly set off on our hike.

Herpetologists exploring Grasslands National Park during our 2009 CHS field trip

It was a little on the cool side, but we had clear skies and sun, which created reasonably good basking conditions for snakes—our primary focus that day. Several snake species in the park—Prairie Rattlesnakes (Crotalus viridis) and Eastern Yellow-bellied Racers (Coluber constrictor flaviventris) in particular—hibernate communally and can often be observed in large numbers basking at the entrances of their hibernacula in the spring and fall. Hopes were high that the timing and conditions would allow us to observe these congregations.

A Yellow-bellied Racer soaking up the morning sun on a cool fall day in Grasslands National Park

After an exhilarating hike through rolling hills and valleys, we arrived at our destination. It didn’t take long before we saw our first Prairie Rattlesnake…and then another…and another! We saw around 20 adults and juveniles that day and were thrilled to also come across several groups of neonates that had just been born within the last few days. Before the day was over, we also saw Eastern Yellow-bellied Racers and some strikingly-coloured Plains Gartersnakes. That evening, field trip participants were invited to join a banquet held at the Val Marie Community Centre, which was a nice way to wind down after an exciting day in the field and meet the local community.

Adult (left) and neonate (right) Prairie Rattlesnakes hanging out at their dens during the 2009 CHS field trip

We were back out in Grasslands National Park for the second day of our field trip—this time in search of Greater Short-horned Lizards (Phrynosoma hernandesi). These tiny lizards, which grow to an average adult size of only 50-70 mm snout-vent length, are very well camouflaged and almost impossible to see unless one happens to catch a glimpse of movement. Fortunately, we had some help—we were accompanied by researchers who were studying these lizards using radio-telemetry. The study animals had tiny radio transmitters temporarily affixed to their backs, allowing us to pinpoint each animal’s location using a radio receiver and antenna. In addition to finding several of these cool little lizards, we also learned a great deal about the Greater Short-horned Lizard’s habitat use, movement patterns and population dynamics, as well as some tricks and tips for conducting visual encounter searches for this species. To learn more about this species, check out Nick Cairns’ CHS blog: Life, Change and Philopatry on Bearpaw Shale.

The timing of the annual CHS field trip provided an opportunity to observe an impressive herpetological phenomenon—the mass congregation of snakes as they gather at their dens in preparation for the long Canadian winter. The use of communal hibernacula by some species of snakes can make it easier for us to observe and study them, but it can also present conservation challenges, since the loss of a single hibernaculum can affect a large portion of the local population. Unfortunately, a few years after our visit, a natural slump occurred at one of the larger hibernacula in the park, and the population is still recovering from that event. Such situations showcase both the fragility and resilience of wildlife populations, pushing and pulling in a precarious balance—a balance that is now too often disrupted by additional pressures imposed by human activities.

Stay tuned for the next blog in this CHS field trip series, in which we’ll explore the wilderness around Thunder Bay, Ontario in search of some of our more northern herpetofauna species.