The principle of the method is to make as many pictures of the species as possible within the study area during a pre-defined period of time and then to estimate the number of specimens by means of capture-recapture statistics. Validity and power of the results depend above all on the sample size, so on the number of pictures taken from different individuals. For a species with such a low average population density as Eurasian lynx, the sample size is always a problem. Nevertheless, the minimum number of lynx present in the area can all the same be evaluated. Furthermore, information on the whereabouts of known individuals is gained, and occasionally, reproduction success or dispersal distances can be documented.