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Western Chorus Frog
(Pseudacris triseriata)
Description: Western Chorus Frogs are brownish-beige with strips running laterally and dorsally. These strips usually run across the eyes and their bellies are generally tan. The toes of Chorus Frogs are only partially webbed and have very small "suction cups" at the tips (compared to treefrogs). Chorus frogs are very small (1 1/4" snout to rump length) and are usually only seen during the breeding season. The Western Chorus Frog is a member of the family Hylidae, which includes most treefrogs worldwide. Within Wisconsin, they are most closely related to Spring Peepers, with which they share the same genus (Pseudacris).
Habitat/Ecology: Chorus Frogs prefer marshes and ponds located near meadows or damp woodlots. They can be found in areas that have been disturbed by humans. Chorus Frogs do not spend as much time in water as do other frogs, such as Leopard or Green Frogs. Although they may be found near ponds or wetlands when not breeding, the only time that I have witnessed Chorus Frogs actually within a body of water is during the breeding season. When not breeding, they can be found under wet vegetation or wood (especially in lowland forests). These frogs eat a large range of invertebrates, including insects, slugs, and worms. Although I assume they would be readily consumed by several predators (i.e., snakes, birds, raccoons), they are very secretive frogs that are probably the most vulnerable while breeding (when they are more exposed to predators).
Remarks: Chorus Frogs are on of the earliest frogs to call in Wisconsin (behind the Wood Frog). Males will call from late March (or as soon as the ice melts and temperatures rise) through June, and can be heard calling concurrently with Spring Peepers, Leopard Frogs, and Wood Frogs to name a few. Their call is a series of short "croaks" that sound similar to someone running their fingers down the teeth of a metal comb. I have witnessed Chorus Frogs breeding in the Myrick Park Marsh (La Crosse River Marsh) for two consecutive years (2000 and 2001) and I would guess that they have bred there for many previous years as well. It is possible that the flood of 2001 affected their numbers. During the flood, I witnessed many males calling in areas that are not normally submerged. If these water levels receded before any eggs laid here hatched, it is possible that many egg were lost. However, this is merely conjecture and it would be interesting to know how these little frogs respond to flooding. I would assume that they also occur in other areas around La Crosse, such as Goose Island and near Green Island.
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