Spring Peeper (Pseudacris crucifer)
by Jeff LeClere
Spring peeper, Pseudacris crucifer, calling.
A valid fishing license is required to possess this species for bait or food. Formerly listed as threatened in Iowa. The public has been very helpful by taking part in the DNR Iowa Frog and Toad Survey as new locations for this species have been found by those participating in the survey.
The spring peeper is one of the smallest frog species in Iowa. They are from less than one inch to 1 1/2 inches in body length. Ground color varies from gray to different shades of brown. Some specimens appear rust red or orange. Like many other frogs, shade of color is affected by temperature. There is a distinctive dark “X” on the back. There also may be random dark dashes on the body. There may be a dark stripe that starts at the snout and continues through the nostril and eye to the posterior edge of the tympanum, and a bar on the head connecting the eyes. The legs have bars on them. The plain belly is a slightly lighter shade of the ground color. Spring peepers have tiny toepads; much smaller than those of the larger treefrogs.
There are no subspecies of Pseudacris crucifer recognized.
Spring peepers are found in woodlands in eastern Iowa. Recent records extend their range to scattered locations in central Iowa.
Spring peepers are a woodland-woodland edge species. They are not often found in open areas or large bodies of water. Smaller wetlands, even some that may dry up later in summer, are used for breeding by spring peepers.
Spring peepers are heard early in spring not long after ice melts on the wetlands. Their normal breeding season lasts from April through May. They make a distinctive ascending “peep peep peep” much like that of a baby chick’s peep. A large chorus can be ear splitting up close! Eggs are usually laid in small clusters. The small tadpoles transform in about three months. Adult peepers do not move far away from the breeding site during summer in the more open areas. Peepers from the deep woods will move some distance, especially during rainy weather of if there are many small pools of water in the forest.
Spring peepers overwinter on land. They allow the water in their bodies to freeze except converted glucose flowing through the organs to keep ice crystals from forming just as in the gray treefrogs. While their overall range is expanding in Iowa, some local populations of spring peepers are declining in abundance in Iowa. I have noticed this decline in populations from northeastern Iowa in just five years. The clearing of woodlands, especially around ephemeral pools, and the draining of these pools, are thought to be the main cause for this decline.
Spring peepers feed on small invertebrates. They do not climb high into trees but hunt in low vegetation. Specimens in deep damp forests are active hunters both day and night, whereas those found in woodland edges restrict most hunting and activity to night.