Here are some pictures I took on the 21st of October 2013. I've had the amazing chance to be in the field on the day of some Vipera aspis births. And in my opinion, I've missed the births only by a few minutes as some of the babies hadn't even shed yet and they were all together very close to a skinny female.
And a bit further in the same spot, I've seen some tens of other babies:
At the end, I couldn't count all the babies I had seen but probably more than 20! What an amazing day it was. I'm still missing the mating of Vipera aspis but at least, I've had the chance to witness something even rarer