You can learn to recognize frog and toad calls by listening to recordings on Web pages, tapes, or CDs. But even if you don't have access to recordings, don't give up! A lot of the calls are easily described in words.
The frogs pictured here are the eight kinds that the Toronto and Region Conservation Authority is tracking with volunteer help. The frogs are spread widely enough across North America that you will probably hear some of them where you live, too.