On the night of May 1, 2010, I camped at the Energy Lake Campground in Land Between the Lakes, Kentucky. I was lucky—there was one site left by the lake and at water’s edge I discovered a large concentration of Fowler’s Toads (Bufo fowleri). As soon as most of the campers had retired for the night, I hauled my gear down a steep slope and got enough footage to put together a nice portrait of the species:
Fowler’s Toads look a lot like American Toads, but can be told apart by subtleties in their wart patterns and by the shape of the ridges just behind their eyes. The two species often hybridize even though their breeding calls are quite different. The American Toad has a long melodic trill that usually lasts more than five seconds. It is dreamlike in quality (see my previous blog post The Dream of the Toad). In contrast, the Fowler’s Toad makes a harsh, nasal trill lasting only a couple of seconds. It is hard on the ears and a chorus can be rather overwhelming (although I think they sound nice when heard at a distance).
In areas where the two species overlap, American Toads typically breed two or three weeks before Fowler’s Toads, reducing the chance of hybridization. Hybrid males generally have breeding calls that are intermediate in harshness and length between the two species—they are nasal yet somewhat musical in quality, and have a duration of several seconds. I’d play you an example, but I don’t have one (what, me, not having an example . . . how can that be?). What I do have, though, is a photo of a male American Toad happily mounted on top of a Fowler’s Toad (I believe a female):