Over the next few weeks we will see more spring-like days and increasing daytime temperatures. A run of such days will trigger the emergence of adders from the sites in which they have spent the last five months. These sites are known as hibernacula and each one is likely to hold a number of adders, wintering communally. Although some individuals may have already made a brief appearance, the peak emergence in Norfolk spans March and April. Initially, the adders will emerge on warm days to bask in the sun, something they will do on and off over a period of days or weeks, before dispersing away from the hibernaculum in search of a mate. This period of ‘lying out’ provides an ideal opportunity to study these wonderful creatures. I have watched and photographed adders around Thetford for the last couple of years. This year, however, I will be taking a more detailed interest in these snakes by collecting information for a survey being coordinated by the Herpetological Conservation Trust. The Trust wants to monitor the fortunes of this species by carrying out counts at sites across the country. By doing so, they hope to find out if, as has been suggested, adder populations are in decline. If you have a piece of heathland near you, why not get out and see if you can locate and monitor a hibernaculum.
Hibernacula are usually located close to a fallen tree, within a root ball or an embankment. Within Thetford Forest, it is the old snag lines that seem to be favoured. Newly emerged snakes will bask close to the hibernaculum, out in the open on bare ground. This makes it possible to observe the snakes without having to approach them too closely and I find that a pair of binoculars is ideal for the task. The adder is a rather short and stocky snake, the males reaching up to 60cm and the females 75cm. They almost invariably show a clear wide zig-zag pattern along their back and a ‘V’ or ‘X’ marking on their head. There is a clear difference in colour between the two sexes (best seen in adults). Males are usually light-grey or cream with a jet black zig-zag, while females are sandy or pinky-brown in colour with a dark tan zig-zag. Both sexes show the characteristic red eye and vertical black pupil.
As our only venomous animal, the adder has had an undeserved bad press. Like all wildlife, they should be treated with respect and valued as part of our natural fauna. Why not do your bit to help them by taking part in the survey. For more details: phone 01986-872016 or email firstname.lastname@example.org