Conservation Corner

Small Frogs, Big Noises

By Dan Zarlenga, Missouri Department of Conservation

Being the third month of the year, March seems a fitting time to look at a special trio of outspoken amphibians. Actually, “listen” might be more appropriate since you’re much more likely to hear than see them.

One of the biggest delights in March is an evening stroll somewhere near water. Temperatures are warming up and the evenings are often cool, calm, and comfortable; conditions that bring out the singing instincts of several Missouri frog species. As winter winds down and spring spins up, the after dark hours come to life with the performances of three crooning critters. They are spring peepers, boreal chorus frogs, and southern leopard frogs.

Each has a unique song, which the males sing to attract females of their species for mating. They perform their music at small woodland ponds, creeks, or swampy and marshy areas. Sometimes they’ll even use a flooded ditch or ephemeral pool. These pools only form during the spring rainy season. They hold water just long enough to harbor the frogs’ eggs after mating and provide the newly-hatched tadpoles a safe environment to develop into adult frogs.

One thing these bodies of water all have in common, though, is no fish. Otherwise, the finned predators would eat the eggs or the young before the frogs would have a chance to grow.

The earliest of the frog trio you’ll normally hear is the spring peeper. True to their name, their call is a bright, high-pitched “peeping” sound. When a large enough mass of them sings all at once, the noise can be ear-piercing! The sound may be big, but the frogs themselves are tiny. Spring peepers only grow to 3/4 -1 1/4 inches long. “X” marks their spot because peepers have a distinctive cross-shaped pattern on their backs.

Southern leopard frogs join the performance soon after. Their voices are somewhat lower in pitch and consist of a series of abrupt, quacking or chuckling sounds. It’s almost as if they were laughing at some joke we humans don’t get. These frogs, though still small, grow a bit larger, from two to three inches in length. Not unlike their feline namesakes, southern leopard frogs sport rounded or oblong spots on their backs.

Laying down the harmony for these nighttime concerts are the boreal chorus frogs. Their songs are sort of a continuous, mechanical trilling. Many liken it to the sound a fingernail running over the teeth of a pocket comb. These frogs are about the same size as the miniature spring peepers. Boreal chorus frogs have three wide, dark stripes down the back, and a wide, dark stripe passing through the eyes and going down along their sides.

So why not take some time to enjoy the enchanting evening serenade? You may never see the singers, but now that you know what to listen for, you won’t miss their songs.

For information visit www.MDC.mo.gov.