If you’ve been out and about in the evening recently, you may have noticed some new voices piping up near the campus ponds. Breeding season has started for Minnesota’s frogs and toads — and we have some of them living right here, in the Arb!

This means that our frog and toad surveys have also begun. The first survey took place last week, and the second survey is scheduled for the end of May. During the survey, Student Naturalists and Carleton students walk through the Arb at dusk, stopping at various sites to listen for the frog species we hear calling. We rank them from one — very few calls — to three, which is a full chorus. The survey is part of the broader Minnesota Frog & Toad Calling Survey, which is important to track the range and health of the different species.

But what species do we track? The very first frog, which appears in April, is the Wood frog. Right now, though, we’re most likely to be hearing Western Chorus frogs, which form a namesake chorus of high-pitched peeps,as well as the Northern Leopard frog. Later in the spring, we’ll be looking out for the American toad with its distinctive trill, and the Gray and Cope’s Gray tree frogs. Around midsummer, the Green frog and Bullfrog may make their appearance. 

For those intrigued by these descriptions, a few of the ponds in the Arb with the most amphibian activity are Kettle Hole Marsh, Oxbow Pond, and Turtle Pond. The frogs are most active around dusk. You are also welcome to join the second frog and toad survey—just look out for an email with the date in mid-May! Finally, if you’d like to learn more about the Arb’s frogs, look for the amphibian guide on the Arboretum website!