Wildlife Matters with Jeremy Holtz
4:00 am
Thu May 22, 2014

Frogs Bring Spring Feelings

Among the joys of spring is hearing the frogs in Northwoods wetlands. 

A chorus of frogs is a sure sign of springtime in the Northwoods.
A chorus of frogs is a sure sign of springtime in the Northwoods.
Credit Pam Fray via commons.wikimedia.org

This morning on his series "Wildlife Matters", DNR wildlife biologist Jeremy Holtz says the amphibian chorus has deep meaning for the ecosystem.

I was hired to work in Northern Wisconsin just over eight years ago. My wife and I were spread thin; she had a newborn baby and a toddler back home in southwest Minnesota. I was doing some travelling back and forth, starting the new job, getting set up housekeeping. It was a stressful time. I remember every time I left the family, I was stressed out and wound up tight. As I got north of Wausau, and into the woods, something happened. I could hear the frogs. I would roll my windows down, and the cool, damp air would rush in. Every depression and valley would vibrate with the sounds of singing frogs. This would begin to relax me, cheer me up, make me feel like I was returning home to where I belonged.

Now, every spring I can’t help but get excited when I hear the chirping of the chorus frogs and the chuckling of the wood frogs. I have been standing in the woods at sunset motionless, trying to absorb the song through the skin, trying to burn it into my memory. Really, we hear frogs and toads sing through much of the summer here, even if we don’t think of the bullfrog’s “jug-o-rum” as a song. We have an assortment of wetlands here in the Northwoods, but right now the ephemeral wetland is the star.

You may not have heard the phrase ephemeral wetland, or know them as vernal pools. Very simply, an ephemeral wetland is a low spot that catches and holds water for a portion of the year. Ideally, the water lasts from snowmelt through spring into at least part of the summer, but not always. These ephemeral wetlands are crucial for a variety of wildlife. Naturally, frogs use them to breed and lay eggs in the spring. Salamanders travel on wet evenings to get back to their natal pond, or pond where they hatched, to breed and lay eggs themselves. Puddle ducks like mallards like to use these wetlands to strengthen pair bonds with their mates as the nesting season begins. These wetlands are dry part of the year, so fish cannot survive in them. Consequently, they are great for frogs, salamanders, and insects that would otherwise face heavy predation from bass and bluegills.

Amphibians (frogs, toads, and salamanders) are in decline across the country and around the world. As I was finishing my college education, I worked on the Boreal Toad Project, an effort to determine how to stop the decline of the boreal toad so we could keep it off the endangered species list. This toad lived at timberline (basically about 10,000 feet above sea level) and had a home range of 5 kilometers. We would hike up to timberline in the early spring and search ponds and streams for this toad. The late 1990’s were when amphibian study really came to stride, following the discovery of several mutated frogs in Minnesota. Today, scientists and concerned citizens across the country are observing wetlands and amphibians in an effort to turn the tide of population decline.

We are truly fortunate in the Northwoods. We do not have carp and bullheads tearing up the substrate of our marshes. Purple loosestrife, and Hybrid and narrowleaf cattail haven’t taken over and choked out our rice, bulrush, and arrowleaf. Timber practices leave buffer strips along lakes, streams, rivers, and wetlands to keep soil disturbance to a minimum and maintain forested shade. We have a lot going for us.

May is American Wetlands Month. Learn more about wetlands and opportunities to volunteer on the DNR website. The frog and toad survey is operated by citizen volunteers, and there are some routes in north central Wisconsin still in need of operators. To learn more, go to the Wisconsin Frog and Toad Survey website. If birds are more your thing, check out the Wisconsin Marsh bird Survey at www.wisconsinbirds.org.