Adders are emerging

25 February 2025
Blog by Henry Barrett

Basking adder – February 2025 – Photo: Henry Barrett

It’s late February now, and the sun is starting to break through and the days are getting longer. It’s around this time of year when the adder Vipera berus, makes its first foray out into the spring sunshine, to bask and recover from a long winter spent in the hibernaculum (place of hibernation). Typically, adders emerge in early spring (late January to early March) though this depends on the weather and will vary in any given year. A changing climate will make this cycle less certain.

Males will emerge first, sometimes in numbers, and spend an extended period of time “lying out”, or basking, in order to regain some of the body condition lost over the colder months. By the time the females emerge, male adders will be ready to compete for the opportunity to mate and pass on their genes to the next generation, which the females will give birth to later in the summer (adders are ovoviviparous, meaning they give birth to live young). This competition will take the form of a “dance” in which individuals display their strength and speed. The dance rarely escalates to real violence, but is an important part of the adders life cycle and a true spectacle – comparable to the lekking of Black Grouse Lyrurus tetrix in its flamboyance.

If you’re out walking in early spring and find several male adders in close proximity to one another, it’s likely that you’re near to the hibernaculum (or hibernacula). Consider yourself lucky, as these features are difficult to find, and incredibly important for adder conservation. Adders are site-faithful and will use these structures year-on-year. It’s vital that we protect these features from disturbance or damage, so please, be an adder advocate and submit your records to iRecord or email Henry Barrett, Conservation Officer – the more data we have to inform our conservation actions, the better. Happy spring.

Adder emerging from hibernaculum – February 2025, NPNL Photo: Malcolm Wilkinson

Constructed hibernaculum – Photo: Henry Barrett

If you would like to contribute to adder conservation in the North Pennines National Landscape, please visit our events section  to sign up to one of our volunteer adder survey events. To find out more about the NPNL’s Adders Up project and opportunities, please contact Sarah Ingwersen, Education and Engagement Officer, or Henry Barrett, Conservation Officer. Remember to contribute your wildlife sightings to iRecord.