Chances are very good that you are hearing the breeding chorus of the wood frog. This is a handsome frog whose body coloration varies from tan to reddish dark brown to almost black. Much of this breeding activity takes place in vernal ponds.
Vernal ponds are an important part of the food chain.
Temporary bodies of fresh water Vernal means spring, and the ponds are full of water for at least two months during the spring. Vernal ponds generally dry up in the summer months. Vernal ponds are typically small - rarely exceeding 150' in width, and sometimes measuring only a few feet across. They are fishless - ponds that dry up cannot support fish populations, a factor which is very important to the unique ecology of vernal ponds. Most of the vernal ponds on Cape Ann occur in woodland areas.