Published April 13, 2011, 02:11 PM

Wild Side: Spring peeper calling

When the ice melts on the ponds in our valley the frog chorus begins. It’s a great sound announcing that spring has arrived. We are serenaded in the evening with stereophonic frog and toad music from the three ponds close to our house.

By: Dan Wilcox, outdoor columnist, Pierce County Herald

When the ice melts on the ponds in our valley the frog chorus begins. It’s a great sound announcing that spring has arrived. We are serenaded in the evening with stereophonic frog and toad music from the three ponds close to our house.

Their calls are about sex. Most frog and toad calls are males advertising to attract females to mate. Some calls are aggressive, made by males toward other males to defend mating territory. Some are release calls to tell a male to let go – frog and toad mating is a wild affair. Each species has its distinct voice. It’s possible to listen closely and distinguish their specific voices among all the calling.

America toads give off long trills four to twenty seconds long. Their throats puff out like a balloon when they call. Toad calls are so emphatic that the vibrations from their throat sac cause the water to bubble. Their warty skin contains poison glands that give them some protection from predators.

Spring peepers are small frogs less than an inch long. They are brown or gray with a light belly and a darker cross on their back. They make high pitched peeps about 20 times a minute. They often call during the day during light rain or cloudy weather.

Western chorus frogs have a white or cream stripe on their upper lip, bordered by dark stripes under their eyes. They are greenish gray with three dark stripes down their back. Chorus frogs make a call that sounds like “cree-ee-ee-ee-eek” that rises in speed and pitch. It sounds like running a fingernail over a fine-tooth comb.

Northern leopard frogs are two to three inches long, green or greenish brown with rounded brown spots bordered by yellow or white. They are often found far from standing water but they congregate in ponds to mate. Leopard frog calls sound like rubbing a balloon – a low rumbling snore. Leopard frog males and non-receptive females make a “chuckle” release call when grabbed by a male trying to mate.

Eastern gray tree frogs are one and a quarter to two inches long, gray to brown with large toe pads, light spots under the eyes and bright yellow or orange on the underside of their hind legs. They make a loud trill lasting up to 30 seconds. If a male detects a female nearby, he makes a longer and louder “courtship call.” Eastern gray tree frogs call from the safety of vegetation near their shallow water breeding sites or from overhanging branches. The males call aggressively to establish and defend their territories.

Green frogs are common frogs in our area around more permanent water bodies. They look like little bull frogs with large tympanums (ear drums). Their call is a single note that sounds like a loose banjo string. Female green frogs choose their mates based on suitability of habitat for egg laying. Smaller males often “sneak in” to mate with females attracted to a larger male’s calls.

Frogs are considered to be good indicators of habitat quality. They lead a fascinating “double life,” starting as fertilized eggs in the water, hatching as herbivorous tadpoles and then metamorphosing into carnivorous adult frogs that breathe air and hop around on land. This aquatic-terrestrial life history and their permeable skin and eggs make them vulnerable to habitat change, contaminants and diseases.

Worldwide, amphibians are in trouble. About one third of the approximately 6,300 species are endangered. Deforestation in the tropics is the biggest factor contributing to their decline. An emerging disease caused by a chytrid fungal pathogen is associated with the loss of hundreds of species.

Twelve species of frogs occur in Wisconsin. The DNR lists one species (northern cricket frog) as endangered and three species (boreal chorus frog, American bullfrog, and pickerel frog) as “special concern.” Annual toad and frog surveys by the DNR and volunteers have found that most of the frog species are holding their own or increasing slightly in recent years.

We enjoy the musical frog chorus in the spring, leopard frogs leaping through the wet grass, toads in our garden and gray tree frogs stuck to our windows on rainy summer evenings. Our valley and our lives are animated by their presence.

Please send any comments and suggestions for this column to me at rfjwild@rivertowns.net.

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