do they think itos all over ?

Just paid a visit to two of my favourite adder sites in superb weather (19 deg C, good sunshine) and seen a grand total of 1 (baby) adder.  Now it could be that I was just being unobservant (but saw 30 at one of the sites a few weeks ago), but it made me think perhaps adders (and other reptiles) are more driven to go underground more by decreasing daylength rather than temperature.  After all, once feeding, breeding and birthing is over, what's the point of laying out and metabolising your fat reserves faster than in the cool underground ?   Any thoughts ?

Cheers

Will

After John Newton found several out yesterday in Yorkshire on a calm sunny day I went up on the Peak District Moors today and found 4 males quite easily at a couple of the hibernation sites, despite the very gusty wind and only intermittent sunny spells. In his 1997 book Derek Whitely had the latest record in the Sheffield/Peak District area as 20 October. However as his earliest record in those days was 22 March and we regularly get them out in early February now, if the weather stays right we could extend the records to the end of the month, leaving them with a very short hibernation period.
PS. The earliest record is now the one Derek managed to find out on 31st January this year.