Adders seen throughout the year in National Park in the Netherlands

An Adder (Vipera berus) was seen by Peter Keijsers in De Meinweg on December 28th 2015. In recent years, we see more and more sightings of the Adder early and late in the year, even in the winter months, but a sighting in December is exceptional, especially so late in the month. The milder winters and rising temperatures in autumn and spring mean the Adders are active for longer. Moreover, the snakes sometimes emerge from their hibernation site on warm winter days. Although there is only a small chance of seeing an Adder in the winter, it is well worth the effort to look near known hibernation sites. The first adder of 2016 has already been sighted, namely in the more northern province of Drenthe on January 10th.

Snake Portal

Observations made by the members of the WAN (Working group for Adder Research of the Netherlands) are kept in the Snake Portal. Here, the members can upload data to help with investigations into Adder populations, such as information about field trips, the numbers observed and photos of the head scales for the recognition of individuals. The observations in the Snake Portal show a similar pattern over the years. The males come out of hibernation early in March and the females a few weeks later. In early October, the animals start returning to their hibernation site. Winter sightings form a nice addition to the known patterns.

Research on the Adder in 2016

In 2016, members of WAN will be actively engaged in research in more than twenty areas in the Netherlands. Current information can be found on their Facebook page (in Dutch).

Text: Pedro Janssen, WAN & Kris Joosten, RAVON
Photos: Peter Keijsers