The Use of 65 Zn for Estimating Populations of Carnivores

Carnivore populations are difficult to measure by conventional methods. We have developed a new method which involves catching one or more individuals from a population and injecting them with the isotope 6 Zn. The radio-isotope appears in the faeces and assuming that the proportion of labelled to unlabelled faeces will equal the proportion of labelled to unlabelled individuals it is possible to estimate the size of the population. We have shown that the method gives an accurate estimate for a population of captive badgers of known size and we have used it in the field to estimate the sizes of wild badger populations.