Minnesota Frog Opera A midst the symphony of sounds emitted from a shallow pond on a spring or summer night, a listener may not realize the social interactions taking place at the water's edge. Male toads and frogs gather at breeding sites and announce their presence with what is known as advertisement calls. When one male calls, others soon call back in contest, creating a rising chorus that falls slowly silent. Each of Minnesota's 14 species has a distinct call used to attract females of the species. Although an individual species tends to breed at the same time each year, fluctuations in weather can cause variations.
Wood frogs breed early in the spring, taking advantage of temporary wetlands.
They are called explosive breeders, meaning they gather in large numbers, but only for a few days. Prolonged breeders, such as gray treefrogs, can be heard calling for several weeks. Other calls produced by toads and frogs include aggressive calls made by a male when another male enters his breeding territory and rain calls, made after the breeding season and may be related to changes in the weather. As males congregate and call at the breeding pond, the larger more aggressive males are able to defend the best egg-laying sites and will attract the most females. Females respond to the calling males by moving around a breeding pool, going near several males before selecting one to breed with.