Neat observation. Jeff !
Although I never saw a pine snake IN the water, I did see a smallish-to-middling one in the talons of an osprey just after being snatched from the surface of Wading River. The Osprey didn't know what he'd gotten himself into. Any self-respecting osprey should have handled that snake's dead weight with no problem. However, because the snake (I'd estimate between two and two-and-a-half feet in length) was gripped somewhere in the lower third or quarter of the body, it swung beneath the bird in a pendulum-like manner. The pendulum's swing, combined with a bit of understandable writhing combined to so unbalance the poor fish hawk such that, although it it had gained maybe 50 feet of altitude, it slowly lost height and made a decidedly inelegant crash landing in a pine at the edge of the bog I was working in. That was one of the old Pomona Fruit bogs. The snake was clearly and boldly marked black and white, so was certainly a pinesnake, and it was dropped by the osprey during the "landing," but I couldn't find it when I got to the region of the tree. The osprey had finally gained a perch on a branch and was just sitting there, winded and pooped! Didn't even think of flying off even with me walking around looking at him (her?) from less than 20 feet away! Understandable, as it was a God-awful hot and humid day - had to be close to 100 with humidity in the high 80's or 90's. You know, I'm sure, of the sort of day of which I speak!
Thanks, Jeff, for calling that episode to mind. I'd really be curious as to other sightings of any aquatic tendencies in the pinesnake. Come to think of it, I did see a big bull snake (same species as the pine snake, different subspecies) in the shallow Little Missouri river in Harding County, South Dakota, in the early 70's. I agree; it's pretty unusual!
Best t'y'all,
Dave