For one of our native species of snake, the adder, September is a key month with changes in behaviour. Approaching the autumn months, adders will begin returning to their overwintering sites from September with individuals often being site faithful. Once back towards these sites they will still spend time basking until late October when it is likely overwintering behaviour will begin.
September can be a great month to spot adders as they will be basking in the open for longer periods of time in sunny spells as the season starts to cool. Our adders are identified by a dark ‘zig-zag’ pattern running down their backs, a red iris with a vertical pupil and usually body lengths of 60 – 80cm.
Overwintering sites, or hibernacula, are often found on sunny, south-facing embankments. These sheltered spots will offer protection from frosty weather, wet conditions and also from predators. Old mammal burrows, accessible tree stumps/root systems, tussocks, rockeries and piles of dead wood are good examples of places an adder can call home for the cold winter months.
Adders are known however to bask in some quite cold conditions if it is sunny. Basking areas will have to be exposed to the sun of course, but adders will prefer areas with long vegetation nearby, usually their own bodies length away in case of passing predators.