A five year study of an adder population Vipera berus in the Swiss Jura mountains number of animals and discussion of population estimate methods Resultats de 5 annees de suivi dune population de Vipere peliade Vipera berus dans le Jura Suisse estimation des effectifs et discussion des methodes destimation
Ursenbacher, S.; Monney, J.
Bulletin de la Societe Herpetologique de France 3eme trimestre; 107: 15-25
In order to estimate the number of adults in an isolated population of adder (Vipera berus) in the Swiss Jura Mountains, several methods were compared. Eighty one periods of capture were conducted during the five years study with the number of periods varying from 8 to 26 each year. The methods for estimating closed populations gave more reliable results than methods for open populations. The software CAPTURE (Otis et al. 1978) seems to give the most convincing estimations and appears to be the prime method for estimating viper population size. The selected site accommodates about 50 adults and the density is appr. 1 adult per hectare, a relatively low level compared to the density observed in other populations in the Alps.