Why Are Spring Peepers So Loud?

United States Geological Survey

Hearing a chirping chorus of spring peepers means winter is on its way out. Their unmistakable calls are synonymous with robins, forsythia, crocuses and marsh marigolds.

Spring has sprung.

But who are these peepers, and why are they making such a ruckus?

At a Glance: What Are Spring Peepers?

  • Spring peepers are small tree frogs native to much of the eastern U.S. and Canada. They often live in marshy woods or near ponds and bogs.
  • Spring peepers begin their calls in early spring and continue through the mating season in early summer.
  • Spring peepers are only about 1.5 inches long, but their calls can be heard up to 2 miles away.

What Are Spring Peepers?

Spring peepers are small tree frogs native to most of the eastern half of the U.S. and Canada. Though only a little longer than a paperclip, these vocal amphibians make their presence known through a distinctive call that heralds the start of spring.

Peepers belong to the genus Pseudacris, a term commonly believed to mean “false locust.” Frogs in this genus are called chorus frogs, and, like locusts, they have a distinct call that we often hear when these animals are in groups. The full scientific name for the northern spring peeper is Pseudacris crucifer.

What Do Spring Peepers Sound Like?

Male peepers emit a series of high-pitched chirps when the mating season begins in early spring. This call is often compared to the ringing of sleigh bells, the chirp of crickets or the trill of a young chicken. This sound is distinct from that of other common amphibians in our region, like the banjo-pluck sound of the green frog or long birdlike song of the American toad.

Peepers are LOUD – as loud as a motorcycle from 25 feet away, or as loud as a chainsaw if the frogs are in a large enough chorus. Careful listeners can hear spring peepers that are as far as two and a half miles away. It’s quite the impressive feat for a frog less than 1.5 inches long!

Peepers produce this cacophony by closing their nostrils and pushing air over their vocal cords and into a vocal sac under their throat. The sac then swells to the size of the frog’s body and amplifies the sound.

Why do peepers put so much work into their songs? Love! The faster and louder a male calls, the more likely he is to attract a mate. Some less musically gifted fellows – called satellite males – will position themselves near louder males to intercept attracted females.

What Time of Year Do You Hear Peepers?

Spring peepers typically start their calls in early March, as soon as winter ice thaws. These chirps are among the first signs of spring.

Peepers can start their mating season earlier than other frogs because of the way they handle winter temperatures. While many amphibians burrow in mud to prevent freezing, peepers stay in the shallow cover of leaves and bark. The outside of the frog’s body freezes, and its heart might even stop beating, but the peeper can survive thanks to a mechanism that prevents damage to its cells. 

United States Geological Survey

By jumping into spring early, peepers gain a leg up on competition and predators still shaking off winter lethargy. Their mating season typically runs from about March to June in northern areas, and from November to March in the southern U.S. After mating, females lay up to 1,000 eggs in pools of water. Eggs typically hatch in 6 to 12 days, with tadpoles maturing in 45 to 100 days.

When the season ends, peepers usually stop calling – so you’re unlikely to hear them in summer.

What Do Spring Peepers Look Like?

Judy Gallagher, CC BY 2.0 , via Wikimedia Commons

Spring peepers are tiny, well-camouflaged and most active at night – making them more difficult to see than they are to hear.

Adult peepers are less than 1.5 inches long and usually weigh no more than 5 grams, or about the weight of a nickel. Most have brown or olive skin with a dark X pattern on their back (that’s where we get the crucifer in Pseudacris crucifer.)

If you want to peep at a peeper, you’re most likely to find them in marshy woods or near ponds and bogs. Try listening for their call and carefully following it while watching for movement on the ground or on the lower parts of tree trunks. While spring peepers can climb, they prefer to hang out in the debris of the forest floor

Why Are Spring Peepers Important?

Spring peepers fulfill an important ecological niche by eating small bugs like ants, beetles, flies and spiders. They also serve as an important food source for larger frogs, birds, snakes and other animals.

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