Where Are the Toads?

For some reason, we seem to have far fewer toads this year than in previous summers. In earlier years, if I went outside after dark, several toads would almost always be sitting under the light in front of the garage, waiting for bugs. But this year, while I've seen a few toads off and on, there are none in front of the garage.

I have no idea why. There seems to be precious little information about garden toads on the web; Amazon doesn't offer much in the way of books on toads. I'd love to know what happened to them and whether we can get them back.