Rhodamine B as a collective marker for studying movements of small mammals

We present a new method of collective marking (rhodamine B) of small mammals that can be used under natural conditions. We examine the acceptance of marked baits, detection and persistence of the signal on the different kinds of hairs of two small species of rodents. Rhodamine B was ingested by captive animals and their hairs were dyed a fluorescent red coloration and observed over more than 150 days. Preliminary results obtained under field conditions tend to demonstrate that winter and summer movements could be detected by this technique. This new collective marking technique may be of great interest to study population turnover and movements of small mammals between habitat patches; it may represent an important method of assessing con­nectivity and permeability of landscapes by small mammals.