Cope's gray treefrog

Distribution and Habitat

In New Jersey, the southern gray treefrog is limited to Cape May, Cumberland, Atlantic, and Ocean counties. Within this area, most populations are located in southern Cape May County.

Southern gray treefrogs spend most of their time high in the trees, except during breeding season when move to the water’s edge. Bare horizontal branches over water are the preferred calling sites during breeding season. They breed in vernal ponds or swamps, and remain in mixed forested uplands during the rest of the year. Like many treefrogs, these species frequently call on warm rainy days outside of breeding season.

Southern gray treefrogs rely on small freshwater ponds, old fields, and hardwood forests throughout their annual cycle. They breed in a wide variety of natural and man-made basins. Breeding pools must contain water long enough to ensure metamorphosis but dry up by the end of summer, in order to prohibit the establishment of predatory fish. Breeding ponds are located within or near deciduous or mixed woodlands such as climax oak/pine forests.

Diet

Southern gray treefrogs rest during the day and forage at night. They feed on flying insects as well as those found hidden amid branches and leaves. Flies, mosquitoes, gnats, spiders, and ants, in addition to other insects and insect larvae, are included in the diet. The tadpoles feed on algae within their natal ponds.

Life Cycle

In late April and early May, nighttime temperatures exceeding 63°F stimulate the vocal activity of southern gray treefrogs. Although they may call from late April to mid-August, choruses peak during warm, humid evenings in May or June. Males may vocalize from trees, shrubs, or the ground to attract females to breeding ponds.

The female deposits individual eggs or groups of up to 40 eggs on aquatic vegetation and leaf litter within a breeding pond. The egg masses are then fertilized by the male. The female will have laid a total of nearly 2,000 eggs in a season. By laying eggs singly or in small clumps, the female reduces the likelihood of losing an entire clutch to predation or desiccation. The eggs hatch in four to five days and metamorphosis occurs in 80 to 100 days. Following emergence, the young frogs disperse into nearby fields and forests.

During July and August, adult treefrogs migrate to terrestrial habitats surrounding their breeding ponds. Here, they dwell in tree cavities, underneath bark, or inside underground burrows, where they will remain over the winter. Gray treefrogs are able to withstand freezing and thawing due to an “antifreeze” present in their blood.