may be found on the banks of streams, lakes, and ponds. In much of southern Europe, such as southern France and northern Italy, it is found in either low lying wetlands or at high altitudes. In the Swiss Alps, it may ascend to about . In Hungary and Russia, it avoids open steppeland; a habitat in which V. ursinii is more likely to occur. In Russia, however, it does occur in the forest steppe zone. Conservation status In Great Britain, it is illegal to kill, injure, harm or sell adders under the Wildlife and Countryside Act 1981. The same situation applies to Norway under the (The Wildlife Act 1981) and Denmark (1981). The common viper is categorised as 'endangered' in Switzerland, and is also protected in some other countries in its range. It is also found in many protected areas. This species is listed as protected (Appendix III) under the Berne Convention. Despite the convention, it is not protected in Finland because of a reservation. The International Union for Conservation of Nature Red List of Threatened Species describes the conservation status as of 'least concern' in view of its wide distribution, presumed large population, broad range of habitats, and likely slow rate of decline though it acknowledges the population to be decreasing. Reduction in habitat for a variety of reasons, fragmentation of populations in Europe due to intense agriculture practices, and collection for the pet trade or for venom extraction have been recorded as major contributing factors for its decline. A citizen science based survey in the UK found evidence of extensive population declines in the UK, especially affecting smaller populations. A combination of public pressure and disturbance, habitat fragmentation and poor habitat management were considered the most likely causes of the decline. The release of 47 million non-native pheasants and 10 million partridges each year by countryside estates has also been suggested to have a significant impact on adder populations across the UK, with the possibility the reptile could be extinct within 12 years. Behaviour This species is mainly diurnal, especially in the north of its range. Further south it is said to be active in the evening, and it may even be active at night during the summer months. It is predominantly a terrestrial species, although it has been known to climb up banks and into low bushes in order to bask or search for prey. Adders are