March 2nd the day temperature was about 5 °C.
Unfortunately the 2 N.sipedon males that were out in January had not survived the frost and lay dead on the surface. Probably they were sick and did not have the strength to crawl away when the frost had set in.
I have seen this before: snakes that are out in the open in the middle of winter often don’t make it until spring.
I had to open the hibernaculum which gave me a perfect opportunity to check whether the snakes were using it. I found all four specimens of Thamnophis radix and the T.sirtalis pickeringii male hiding in the hibernaculum. Also several of the large Nerodia sipedon females where in the hibernaculum. I could not find all the snakes. I tried to search in the pond to check whether some snakes were overwintering under the water, but that was apparently not the case.
When I was finished I quickly closed the hibernaculum so the snakes could continue their hibernation.
March 4th – 8th there were some mild days with temperatures of 10 – 15 °C and I expect some of the snakes were active but I was not home to check. After March the 8th it got cold again and it remained cold the entire month. The little pond was almost constantly frozen. No snake activity was seen after March 8th.