Thanks. While I don't personally own I do have access to the books you mentioned and will be sure to check out the bit on Brownsnakes this week. There is a recently published book on the anurans of the United States and Canada that is very comparable to Petranka's book on caudates. I can't remember off the top of my head the author or exact title so I'll track it down on monday and get back to you.

Thanks!