The Northern Spring Peeper is a frog that varies in size from 19 to 35 mm at maturity. These frogs range in color from shades of brown to gray or olive, and occasionally may be yellow or reddish. Like many frogs, their color can vary with temperature and other conditions of their surroundings. Their bellies are cream or white, and they are marked by a dark cross on their backs and dark bands on their legs. Their coloration makes them very difficult to see on the tree bark and leaf litter where they are normally found. Northern Spring Peepers have slightly webbed feet and noticeable disks on their fingers and toes. Females tend to be slightly larger and lighter in color. Males also often have a flap beneath their throats where their vocal pouches are. This flap can become much darker than normal during breeding season when they are calling the most.
Northern Spring Peepers are only native to the Nearctic region. They can be found from southeastern Canada, in Ontario and Quebec, throughout the eastern United States as far south as northern Georgia. In the United States they are restricted to east of the Mississippi river. Their cousins, Southern Spring Peepers, inhabit the southern parts of Georgia and northern Florida.
These frogs are found in marshy woods, non-wooded lowlands, and near ponds and swamps. Although they are good climbers, Northern Spring Peepers seem to prefer to be on the ground or burrowed into the soil. Because they breed in permanent or temporary water, they need to have pools in their habitat.
After hatching from their eggs in ponds or pools, Northern Spring Peepers develop as tadpoles for 2 to 3 months. They then undergo metamorphosis, in which they transform into small frogs and begin their life on land.
Northern Spring Peepers begin breeding in the first year after they have hatched. The breeding period lasts from early spring to June, depending on the region. Most breeding occurs in April, although males may continue to call through June.
Females lay between 750 and 1300 eggs. The eggs are laid in small clusters, usually in rows attached to submerged vegetation. The tadpoles hatch in 4 to 15 days and then go through metamorphosis at between 45 and 90 days old.
Northern Spring Peepers have no parental involvement after the eggs are laid.
Little is known about lifespan in Northern Spring Peepers, but it is unlikely that most live longer than 3 years.
Northern Spring Peepers migrate to breeding ponds in the spring. After breeding they disperse again to surrounding areas, such as woodlands and swampy areas, and live relatively solitary lives. They are mostly active at night, though may remain active during moist, warm days. Northern Spring Peepers have home ranges that are from 1.2 to 5.5 meters in diameter, they travel an average of 6.1 to 39.6 meters in a day.
Northern Spring Peepers spend the winter burrowed into soil or under logs and leaves. They survive the freezing temperatures of winter by producing an anti-freeze like substance, glycerol, in their tissues. This prevents ice crystals from forming inside of their cells (thus killing the cell). They thaw and come out of hibernation when warm temperatures return in the spring.
Male Northern Spring Peepers have a unique call. They make a single high-pitched note that lasts about a tenth of a second. They can make this sound because their vocal sacs are bigger than many other frogs. They repeat this note in rapid succession. Their call sounds very much like the peep of a chick and, when they are singing in chorus, they may be mistaken for the sound of sleigh bells.
Though Spring Peepers usually call during mating season, they have a separate call that they use when involved in a conflict or fight. They have also been known to call after rain storms and before hibernation.
Northern spring peepers eat mainly small insects and other arthropods, including ants, beetles, flies, ticks, mites, pillbugs, caterpillars, springtails, and spiders. They will eat almost any animal small enough to fit in their mouth. As tadpoles, however, northern spring peepers graze on algae or decaying plant material in ponds and pools.
Many animals will eat northern spring peeper tadpoles and adults, including large, aquatic insects, snakes, larger frogs, fish, and birds. Their coloration makes them hard to see, allowing them to escape some predation. Also, their habit of congregating to mate at cool ponds in early spring reduces the number of predators that will be around to eat them.
Northern Spring Peepers are abundant predators or small insects and other arthropods, so help to control populations of these animals. They also help to support populations of the animals which prey on them.
There are no negative effects of Northern Spring Peepers.
Northern Spring Peepers may help to control mosquitoes and other small insects in the areas where they live.
Northern Spring Peepers have no special status in most areas. They are common and widespread but, due to loss of wetlands, their habitats are quickly dissapearing. In some areas their populations have decreased significantly. This is especially true in areas where wetlands have been virtually eliminated. For instance, in Iowa, where they are on the threatened species list.
Because Northern Spring Peepers are very tolerant of cold conditions, they are often one of the first frog species to appear in the spring. They may come out as early as February and January in the southern parts of their range, but more typically begin congregating at breeding ponds and calling in March or April. Many people have come to recognize the call of Northern Spring Peepers as a sign of the coming spring.