Spring has sprung and the night air is filled with the familiar calls of our anuran friends. Here is a great page by Dr. Patricia Jones of the University of Michigan Museum of Zoology that has the calls of many of the frogs of our region. One of the most familiar calls is from the Spring Peeper (Pseudacris crucifer). So far this season, I have heard calls from the Wood frog (Rana sylvatica), the Spring peeper, and the Western chorus frog (Pseudacris triserieta triserieta). The call of the chorus frog can be sometimes confused with the aggression call of the spring peeper. Spend an early spring night by a wetland or pond and see how many frog calls you can identify.