Peepers' song is a sure sign of spring
What is that din that echoes so loud?
A lone spring peeper standing proud.
Those may not be the words of Alfred Lord Tennyson but they ring true enough. For a diminutive animal, the size of a thumbnail, spring peepers make quite a bit of noise. A pond full of males peeping out their mating call is a sign that warmer weather is on the way.
"I think of them as one of two signs of spring," says Mass Audubon naturalist Dennis Murley. "Right around March 21 on most years you hear that good first chorus; I never get sick of that sound. I live right next to a place where it's almost deafening. Some people want to pull their hair out but I have no problem sleeping."
While the odd peeper has been out since mid-January, providing the days are warm enough, the nights have been sufficiently cool so far to keep the full chorus away.
Many people have never actually seen a spring peeper so, for the record, we will note they are frogs, not insects or birds. They return to the water to breed - those are the males calling to the females you hear - but spend most of their days in the upland woods staying quite invisible.
Spring peepers are found in every county in New England and are maybe three quarters to an inch in size, cinnamon brown to gray in color with an "X"-like marking on their back. The X gives them the scientific name Hyla crucifer. On the underside, peepers are yellow to pink.
Females can grow larger, up to just over an inch. When they call, their throat balloons out, almost doubling their size. Many years ago herpetologist Skip Lazell estimated there were as many as 96 million on Cape Cod.
While there may not be quite that many today, there are still quite a few.
"I would consider them to be widespread and common," ventures wildlife ecologist Robert Cook of Cape Cod National Seashore. "Usually we record them in 95 percent of the sites we sample. We find them basically in all manner of freshwater wetlands, temporary to permanent, from Eastham to Provincetown."
Cook conducts many amphibian surveys in the Seashore. He spotted some females crossing roads in Wellfleet on March 8, but the nights have to be above freezing for them to begin calling. They'll also call out on cloudy days.
"Spring calling season generally runs from the mid March to the end of May," Cook says. "Usually there is a drop-off in calling after Memorial Day. But the season for spring peepers extends for the bulk of the year. Spring peepers are a terrestrial species that lives in the upland for most of the year."
According to Mary Dickerson, author of "The Frog Book" written in 1906, the call is pitched between B and E, "two octaves above C." Sometimes a peeper will trill rather than peep. They are territorial, with a "home ground" of 4 to 16 inches. The trill is a sign another male is too close. A male may repeat its call 4,500 times a night. Research has shown that females can distinguish individual male calls.
Like all frogs, they are carnivores, although the tiny peepers can eat only small insects, spiders, mites, slugs, sow bugs and the like. While they resemble tree frogs and have disks on their toes instead of webbed feet, they're usually found in the leaf litter in the summer and fall. They occasionally make "rain calls" in the autumn.
"They call during rainy and humid weather. They don't do it during the dog days of summer," Cook says. "It takes the autumn weather to get them calling again. It's not a chorus, just an individual here and there."
Over the winter they are inactive rather than hibernating.