Individuele herkenning bij de gladde slang - aanvulling op de digitale zoekformule

Recognizing individuals of the Smooth Snake Recognition of individuals is an important part of population research. A search code for identifying individuals of the Smooth Snake (Coronella austriaca) was presented in RAVON 45. It was based on the position of certain head scales and their colouration. The code was tested in the Meinweg area in the south of the Netherlands. Unfortunately, when tested on Smooth Snakes outside this area, individuals which had the dorsal stripes connected with the coloured head scales presented a problem. The authors collected 505 photos of the head of Smooth Snakes from other parts of the country, and found that 111 had a connection between the dorsal stripes and the coloured head scales. This considerable proportion (22%) led to the code being revised on three points. Firstly, in the case of a connected dorsal stripe, counting should be stopped if the dorsal stripe is only one scale wide. Secondly, when two dorsal stripes come together somewhere along the body , the scales in the middle should be counted and belong to code number 5. Thirdly, when the dorsal stripe is two or more scales wide, the counting of coloured scales should be stopped at a maximum of 25. Because the scales that are important for the code are quite small, the authors advise taking photos not only of the top of the head, but also of both sides of the head where some of the scales used in the code are located. These can be used as a back-up after having given an individual a code in the field.