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Inventorying Reptiles and Amphibians

As landowners restoring our acreage to native ecosystems, we inventory reptiles and amphibians. In fact, we inventory all the wildlife. It’s rewarding and directs our land management techniques and timings. We want to protect our wildlife and enhance biodiversity. We view it as our way to “keep all the parts” as Aldo Leopold said and “first, do no harm” as the Hippocratic oath states.

Many reptiles and amphibians are shy and prefer to remain out of sight. Amphibians spend their days under damp logs and rocks to prevent moisture loss. Snakes and lizards prefer to be under objects such as rocks. It’s always best not to handle the animals. And be especially considerate when observing in cooler temperatures. Cold-blooded wildlife are slow moving in cooler temperature. I liken it to that groggy feeling when I first wake up.

We are very pleased to have a nice inventory of herptiles enjoying our land. Restoring habitat for them is rewarding. We are also grateful for our herptile expert who wrote management guidelines for us. 

4 Inventory Methods 

While there may be more, these are the ones I’ve used and find more useful.

  • Physical searching
  • Learn the calls of amphibians
  • Coverboards
  • Turtle surveys

1. Physical Searching

Physical searches include turning over rocks, logs, pieces of bark or other debris. Gently move object toward you. This protects your legs and whoever might be under the item. And gently replace the item as you found it. This preserves their refuge. It’s akin to having someone searching your home for an item; you’d want them to put things back the way they found them.

In the spring, if you have temporary or permanent water bodies on your property, see what you find in and around the water.  Amphibians congregate at these water bodies to breed and deposit eggs.  You may have the pleasure of discovering the eggs or observing tadpoles and salamander larvae. There are 2 excellent field guides listed at the end of this article that can be used to help in identifying the eggs and/or larvae.

Gray treefrogs are attracted to lights as a place to hunt insects. They will show up on your doors and windows during the summer. The suction cups on their toes enable them to “stick” to the glass. Makes for a fun photo opp!

This tree frog was attracted to insects coming to the light in the house.

Old stone foundations, wells, or rock piles are great places to check after a few warm spring days. These make good hibernacula (overwintering areas) for reptiles and amphibians. Garter snakes congregate in large numbers to overwinter before emerging in spring. Once emerged, they hang around the hibernacula pursuing mates and breeding. In spring and before winter are good times to observe herptile species if there’s good hibernacula available.

Human-made rock pile
A self-created rock pile for our reptile friends.

Rock outcropping
A beautiful rock outcropping makes a nice habitat.

2. Learn the Calls of Amphibians

Frogs and toads can be identified by their calls. Calling generally starts when the ice has melted on the ponds. In Wisconsin, there are three basic calling groups. When they begin calling depends on the water temperatures. In general, the first group calls as early as the start of April, the second group follows in three or four weeks, and the last group calls about mid-May.

In the Driftless Area, we only have one toad and its trill is continuous, almost insect like.

Madison Audubon has the perfect CD for a small price. We listened to this as we ran errands and learned the calls in a short time.

 

Take a quiz on frog and toad calls and see how well you know them. This is sponsored by the United States Geological Survey.

3. Coverboards for Herptiles

At our place, most reptiles and amphibians have been discovered while doing other activities. When we uncovered a prairie ringneck snake (Diadophic punctatus arnyi), but didn’t have a camera with us. We decided a new technique was needed.

We created coverboards. These would allow snakes to shelter under them out of the sun. Jim cut 3/8” untreated plywood into 2’x3’ sections. It’s important the wood is untreated. We kept the boards to a smaller size for easily handling and to prevent leaf litter from drying out in the center. Small coverboards are also useful if you have salamanders on your property.

Herptile monitoring board
We strategically placed this near the rocks in early spring.

Herptile monitoring board
Originally we put these 1″ blocks on these board to allow some space but it isn’t necessary.

Larger coverboards are needed when looking for larger snakes such as Eastern fox snakes, Eastern milk snakes, or gophersnakes. Interspersing both sizes will maximize the numbers and variety of animals that you’ll find.

Placing large sheets of tin/metal as coverboards in addition to wooden coverboards can be productive, too. Some animals may find the temperature and moisture differences from the metal more attractive than the wood.

Rainy days are great observation times for amphibians. In the spring, after the ground thaws and there’s a good soaking rain, salamanders can be found migrating at night from their terrestrial overwintering areas to their breeding ponds. These ponds are usually temporary or ephemeral wetlands rather than permanent water bodies. Some salamanders migrate en masse upon metamorphosing from a gill-breathing larva to a lung/skin breathing adult. Observing this migration is awe inspiring!

4. Turtle Surveys

Some turtles can be observed readily, when they are basking on logs or other structures on the water.  This is especially true for painted turtles that bask in groups on the same log. If you live along a large river, you may be lucky enough to observe a basking map turtle species. The Driftless Area is home to three species.

Many turtles are not so evident. For example, the eastern musk turtle is Wisconsin’s smallest turtle. It prefers the bottoms of water bodies as do softshell turtles (both smooth and spiny varieties are found in the Driftless Area).

Blanding’s turtles are found in more stagnant water bodies and are beautifully camouflaged in duckweed covered wetlands.  The bright yellow throat of the Blanding’s turtle gives it away as it floats with its head and neck sticking out of the water. Blanding’s turtle like a sandy area near wetlands to lay their eggs.

Ornate box turtles prefer drier, sandy prairies with deep deposits of sand which allows this animal to survive our harsh winters. This turtle is endangered in Wisconsin and does not occur in Minnesota.  In Illinois and Iowa, it is listed as threatened. You are very unlikely to encounter this turtle, but if you do, you are very fortunate and have a very special neighbor.

Perhaps the best time to observe turtles on your property is during turtle nesting season, when females will come up on dry land and seek a place to lay their eggs.  In some cases, such as softshell turtles, the females will stay near the water to lay eggs.  On the other hand, common snapping turtles and Blanding’s turtles may travel a mile or more from water to find a suitable nesting spot.  Look for areas of friable (or at least diggable) soil with plenty of sun exposure as potential nesting areas.  In some cases, this may be your driveway!

Turtle Egg Cages

We made turtle egg cages when monitoring a wetland area for Blanding’s turtles. These protect the eggs from predators and allow the hatchlings to exit.

We cut 1/2×1/2” hardware cloth to form a box 10” square and 6” deep. Using hardware cloth of this size prevents small rodents and moles from entering the cage. We clipped 4 holes at the top of the cage, each 1.5” wide and ½” high. The sides were held together with wire clips.

Bend the upper horizontal strand of the small opening upward to expand the opening to 5/8″ high. This creates a smooth opening, preventing the wire strands from damaging a hatchling. This opening should be set right at ground level. Hatchlings will encounter it as they move along the cage perimeter.

Eggs are best discovered during a wet period, most likely after a rain. When a nest is found, these cages should be buried so only 1” sits about the soil surface. Ensure that the 4 clipped holes are at ground level.

A nice PDF of the process for building turtle cages.

Resources

There are a multitude of resources available to landowners who are interested in learning which amphibians and reptiles use their properties. These include:

Wisconsin Department of Natural Resources, amphibian and reptile field guides you can order online.

Reptiles and Amphibians of Wisconsin.2004. Stan Tekiela. Adventure Publications.  This includes a CD with the calls of Wisconsin’s frogs and toads as well as the guide.

A field guide to Amphibian Larvae and Eggs of Minnesota, Wisconsin and Iowa. United State Geological Survey. Information and Technology Report USGS/BRD/ITR-2002-0004. 

New Field Guide to Amphibian Eggs and Larvae of the Western Great Lakes. Wisconsin Wetlands Association. 

Amphibians and Reptiles of the Great Lakes region, revised ed. 2017. James Harding and David Mifsrud. University of Michigan Press.

Citizen Science Opportunities

You can contribute your herptile discovery results to the following:

  1. iNaturalist, a platform on which to report local wildlife sightings of all kinds. 
  2. Wisconsin Volunteer Frog and Toad Survey, one of the longest running volunteer frog and toad monitoring programs. 
  3. Frogwatch USA (via AZA). 
  4. Iowa Volunteer Frog and Toad Survey 
  5. Wisconsin Herp Atlas Project 
  6. HerpMapper  

References

Christoffel, Rebecca, email of 10 Februry 2020.

Hay, Robert, email of 25 March 2017

Himmelman, John. 2006. Discovering Amphibians: Frogs and Salamanders of the Northeast. Maine: Down East Books.

USGS. Sampling Techniques and Protocols

Vogt, Richard Carl. 1981. Natural History of Amphibians and Reptiles of Wisconsin.  Milwaukee, WI: Milwaukee Public Museum and Friends of the Museum, Inc.