Fluorescent powder as dye in bait for studying foraging areas in small mammals

We examined the characteristics of fluorescent powder as dye in bait for the purpose of studying individual foraging areas of the root vole Microtus oeconomus (Pallas, 1776). Colours were visible in the faeces 2-3 h after consumption, and were still evident 36-48 h after the removal of bait. It was possible to distinguish up to four different colours in faeces from one individual if the appropriate combination of coloured powder was used. The method is a better alternative to other markers commonly used in bait because only a small extra sampling effort is needed during trapping, and the observation of colours is relatively easy in UV-light. Because the persistance of the colour powder in the animal is relatively short, the method facilitates studies of short-term changes in foraging areas.