I don't know, but a month seems rather pointless. Concinnus' especially, don't "reset" with just a month. They need longer. And yes, of course it's hard to tell when birth may take place without observing copulation but then again, I've never had garter snakes copulate at all until about a week after bringing them out of a full brumation, or in the case of ordinoides, during a simulated fall season. This is just my experience with concinnus and ordinoides of course. All bets are off with CB snakes generations removed from the wild or snakes that have been kept for years without brumating.