Spotlight on... Adder

Adder (Vipera berus)


From the UK three native snake species (adder, grass snake and smooth snake), only the Adder (Vipera berus) is venomous. Although potentially serious, seeing an adder is no cause for alarm as bites are rare and seldom fatal, with most bites having occurred when the snake has been disturbed.

Adders are found in a range of habitats where they can bask in the sun as well as take cover, including heathland, moorland and open woodland. Adders may easily go unnoticed due their secretive nature and camouflage markings.

Adders hibernate from October to mid-February/March. During Spring and Summer, they are usually active during the day, when they hunt small animals, including mice, voles, frogs and shrews and sometimes lizards and small birds.  Mating takes place in April/May and female adders incubate their eggs internally and will ‘give birth’ to up to 20 live young in August or September.

All British reptiles are protected in the UK under the Wildlife and Countryside Act, 1981. Priority Species under the UK Post- 2010 Biodiversity Framework.

Where are Adders?

According to our database, adders are mainly in Berkshire, the Warburg BBOWT reserve and Chiltern commons. However, our database only includes information which people have provided to us (and we have collected), so a lack of records doesn’t mean that ravens aren’t present in the area. All it means is that no-one has told TVERC they’ve spotted them… yet!

Have you seen any Adders?

If you spot any wildlife when you’re out and about, share your records and photos with TVERC. By letting TVERC know what you have seen you will help protect and improve your local environment by increasing the quality and quantity of data we hold. Photographs are always helpful too, as we keep an image gallery of species found in Oxfordshire and Berkshire.

Absence records are also very useful, so also let us know if you’ve been out and haven’t seen anything!

Your records can inform a variety of exciting biodiversity projects and help people make informed decisions about how to develop and manage land sustainably. We are a ‘not for profit’ organisation so rely on valuable help from skilled volunteers to improve our database.

Identification help

Adders are clearly distinguished by a “V” or “X” shaped marking on their head. They also have a very characteristic dark zigzagging line down their back with a row of dark spots along each side. The background colour varying from whitish or pale grey (male) through light brown or brick red (female) body. Typically, adder’s length reaches up to 65cm with females usually longer and wider than males.

The eyes are reddish in colour with a vertical pupil.

Occasionally, there has been sightings of adders which are almost black in colour (melanistic). 

Find out more

Check out the links below for more information on Adders:

Where should we direct our spotlight next?

If you are a recorder, a local recording group or just have an interest in a species, send us your suggestion for a species, along with some facts and a photo (if possible) to