Northern Michigan Outdoors: Springtime is fast approaching—are your senses ready? The sights, smells and sounds are all part of the springtime experience in Northern Michigan, and nature provides some of the most exciting sounds of spring. You may hear birds singing, a spring thunderstorm, frogs and toads chirping and trilling. Wait … frogs and toads? Have you ever wondered how many different sounds are coming from frogs and toads each spring?
There are 13 species of these little critters that call Michigan home. Collectively, frogs and toads are a group of amphibians called anurans, which means "without a tail." Frogs have smoother skin, longer legs and spend more time in the water than toads. Toads generally take short hops while frogs may leap several feet in one jump.
Both frogs and toads require water for at least part of their life cycle. From late winter to early summer (depending on the species), male frogs and toads begin calling for mates from their wetland breeding sites. Each species can be identified by its characteristic call. Calling is not only for the purpose of attracting mates, but to warn other males of their presence and to not enter their territory.
Frogs and toads can “breathe” through their skin via tiny blood vessels that absorb oxygen. To be able to do this, their skin must be kept moist. Thousands of tiny glands in their skin produce mucous to keep them moist. Toads have thicker, drier skin than frogs and lose water more slowly so they don’t feel so slippery. (And no need to worry, toads cannot give you warts!) Frogs and toads are also able to absorb water through their skin so they usually do not need to drink water. This ability to absorb water and air through their skin makes them especially vulnerable to toxins in their environment.
Amphibians are excellent indicators of environmental problems because of their direct contact with gases and liquids in the air, water, mud and leaf litter in which they spend their lives immersed. A worldwide decline of amphibians, including frogs and toads, has been documented since about the 1970s. Although scientists have not discovered a positive reason for the decline, many theories have been offered. Habitat degradation, commercial harvest for food or the pet trade and pollution could all be factors contributing to their decline.
In the spring of 1996, the Department of Natural Resources Wildlife Division launched a frog and toad monitoring program to help track population numbers. Funding for the program comes from the Nongame Wildlife Fund, which is supported through the sale of wildlife habitat license plates and private donations.
The population surveys are conducted by volunteers including professional biologists, herpetologists, university personnel and citizens interested in Michigan frogs and toads. Volunteers are trained on how to distinguish frog and toad calls.
Learning 13 species of frogs’ and toads’ calls is a lot of fun and relatively easy. Each observer sets one or more survey routes in the area of their choice. Observers stop at each site and listen for calling frogs and toads. Each route is surveyed three times in the spring and early summer.
Interested in learning about what different frog and toad calls sound like? Check out the Wisconsin DNR’s "Know Your Frogs" page, where you can learn about the frogs and hear their calls. We have many of these same species in Northern Michigan.