It's probably best not to bother them. Having said that, I'd be fibbing if I said that I wouldn't pick them up to check them out. I'd be curious too. If you go back, shoot a few pictures for us to see. I'm guessing that they're Wood turtles...just a guess. In my experience, wherever Wood turtles occur in any abundance, they communally hibernate. The only other Northeast US turtle that I've heard of doing this naturally is the Bog turtle. When they warm up, they mate and go seperate ways. Also, I could swear that the female Wood turtles will sit in shallow water and whistle, attracting the males. Keep in mind, I'm dealing with a ridiculously small sample size of turtles...just a few populations from my favorite trout streams in PA. At least let us know how they look.