Footprint tunnels detect dormice far better than nest boxes

Footprint tunnels detected garden and hazel dormice far more often than nest boxes in a study in Italy’s western Alps, ERR reported, citing University of Tartu ecologist Marko Mägi.

Nocturnal animals can be difficult to count because people may not see them. Researchers often use nest boxes to study dormice, including the garden dormouse (Eliomys quercinus), but the animals also nest in tree cavities and burrows. As a result, nest boxes may give an incomplete picture of where they live.

The study compared nest boxes with tunnels attached to branches. An animal entering a tunnel gets its paws coated with a mixture of olive oil and activated charcoal, leaving prints on paper that researchers can use to identify the species.

Researchers recorded 573 garden dormice using the tunnels, compared with 27 in nest boxes. For hazel dormice (Muscardinus avellanarius), the corresponding figures were 728 and 126. Garden dormouse tracks were also found in places where none had been recorded in nest boxes.

Garden dormice were more likely to be found where there were more rocks and dead wood, including fallen trunks and stumps. These features can provide shelter, while dead wood supports invertebrates that the dormice eat. Both species were more likely to be detected in shrub-rich areas. The researchers also found that the species compete: the likelihood of detecting hazel dormice in an area fell when garden dormice used a nest box there.

The animals remained active in autumn until December, but they no longer used nest boxes late in the season. The study used nest boxes that had been in the wild for at least three years, unlike earlier comparisons that used new boxes, which animals may take time to adopt.

The researchers concluded that footprint tunnels are a more effective and less disturbing way to detect dormice. Nest boxes remain useful for studying reproduction and population demographics because animals are easier to catch in them. The study was published in the European Journal of Wildlife Research.