Green treefrogs call as summer wetlands warm

The wetlands near Lorton hold the heat of long summer days well into evening. Water temperatures climb through the afternoon, and as dusk settles, the first calls begin. A single note, then another, building into the steady chorus that will carry through the night. Green treefrogs have emerged into their peak breeding season, and their voices now define these warm wetland edges.

The males call from low vegetation along the water's edge, their bright green bodies nearly invisible against the leaves of spicebush and redbud that overhang the shallows. Each call is a sharp, nasal honk that carries clearly across the water. They position themselves just above the waterline, gripping stems with their adhesive toe pads, throats swelling and deflating with each vocalization. The calls come in bursts, each male timing his contribution to the collective sound that draws females from the surrounding forest.

This chorus serves multiple purposes beyond simple attraction. The overlapping calls create an acoustic blanket that helps mask individual frogs from predators. Great crested flycatchers and red-eyed vireos hunt these wetland edges, but the coordinated calling makes it difficult to pinpoint any single frog. The males also space themselves acoustically, each finding a frequency and rhythm that cuts through the mix without directly competing with his nearest neighbors. As water temperatures rise through the evening, the calling intensifies. Warmer water means faster development for the eggs and tadpoles that will soon follow, making these peak summer nights crucial for reproductive success.

The females approach silently, moving through the shallow water to assess potential mates. They choose based on call quality and the male's position, often selecting sites with the right depth and vegetation density for egg laying. Once paired, the female deposits her eggs in small clusters attached to submerged vegetation, while the male fertilizes them externally. The eggs develop quickly in the warm water, hatching within days into tadpoles that will feed on algae and organic matter in these productive summer wetlands. American bullfrogs and green frogs share these waters, their deeper calls providing a bass line beneath the treefrogs' higher-pitched chorus.

Listen now for that steady pulse of sound that rises with the evening air. The calls blend into a rhythm that matches the season itself, urgent but unhurried, as constant as the warm water that holds tomorrow's generation. If you are near water tonight, that chorus is the sound of summer wetlands at their most alive, each voice a small green life calling toward the future in the gathering dark.