The importance of animal food for Dryomys nitedula (Pallas) and Glis glis (L.) In Białowieża Forest(East Poland): analysis of faeces

Fresh faeces of dormice found in nestboxes along the permanent transect in Białowieża Forest were analysed. The study area was a managed forest of diverse biotopes. In total, 196 samples of faeces of the forest dormouse (Dryomys nitedula) and 62 of edible dormouse (Glis glis) were examined. In the faeces analysed, the following categories of food remains were distinguished: chitin carapaces, calcareous shells, feathers, seeds, plant fibres. In the forest dormouse, chitin carapaces were found in 100% of samples, but in only 8% of the edible dormouse samples. Feathers were noted in 36% of samples of forest dormouse faeces, but only in 12% of samples from the edible dormouse. Calcareous shells were found in 14% of forest dormouse samples and 1.6% of edible dormouse faeces. Remains of animal food were found in 100% of samples of forest dormouse excrements, but only in 29% of samples from the edible dormouse. The highest percent of faecal samples with animal remains was found in the edible dormouse in July, while in the forest dormouse seasonal variation occurred only in some types of animal remains. Most of the chitin carapaces identified in forest dormouse faeces came from Chilopoda (45%), Hemiptera (33%) and Coleoptera (22%). In faeces of the edible dormouse the majority were remains of butterflies (55%). The results presented here suggest an almost total separation of the food niches of the two dormouse species.