The sound of spring peepers a reminder spring is on the way
Enjoying spring peepers is a listening experience, not a visual one.
Bird sounds are among the best-known harbingers of spring in the wildlife world. However, in early spring, a small frog begins spreading the message of seasonal change at a time many birds are still warming up their spring calls. And, though the frigid temperatures of the past couple of weeks are still vividly in our memories, these small amphibians will soon be reminding us spring is on its way.
The spring peeper is one of the Ozarks’ well-known end-of-winter signs because it is the earliest calling frog of spring. These small frogs begin calling and breeding in early March (some years in late February) and continue until early May.
Spring peepers grow only to slightly more than an inch in length; most could fit comfortably on the end of your finger. The most noticeable characteristic of this frog is the clear, high-pitched call male uses to attract females. The spring peeper makes this call by closing its mouth and nostrils and forcing air from the lungs over its vocal chords into the lower part of the mouth, which inflates into a bubble and vibrates like a drum. This process produces loud trills. A spring peeper’s vocal sac can inflate to about the size of a quarter. As is the case with all wildlife mating calls in the spring, the more clear and robust the call, the better chances of attracting a female. These calls are heard primarily at dusk and at night, although they can be heard on overcast days during a rain or immediately after one.
Spring peepers survive winter by digging into the soil. As with a number of frogs and toads, spring peepers produce a type of “anti-freeze” in their blood that protects their tissues from damage if they become frozen.
The general color of a spring peeper varies from pinkish to light tan, brown, or gray. Spring peepers also feature a dark “X” marking on their backs. However, as previously stated, describing how they look is basically irrelevant because you’ll hear them far more often than you’ll see them. The spring peeper is primarily a woodland species. It resides near ponds, streams or swamps where there is thick undergrowth.
The end result of all this calling and courtship is egg-laying. One female can lay up to 900 eggs, each egg about one millimeter in size. The eggs are laid singly and are attached to leaves, grasses and sticks in shallow water. They are fertilized by the males as they are laid. The eggs hatch in three or four days and tadpoles metamorphose in about two months. In addition to entertaining humans with their mating calls, spring peepers provide another benefit to us by feeding on flies, ants, beetles and other small insects that can be occasional (or frequent) pests for humans.
More information about spring peepers and other amphibians that call Missouri home can be found at your nearest Missouri Department of Conservation office or at www.missouriconservation.org
Francis Skalicky is the media specialist for the Missouri Department of Conservation’s Southwest Region. For information about conservation issues, call 417-895-6880