Winter feeding behaviour of European rabbits in a temperate zone habitat

Herbivores living in seasonal environments commonly have to deal with reduced food availability and quality during the winter season. The present study investigated how European rabbits Oryctolagus cuniculus living in a grassland habitat adapt their feeding behaviour to cope with this situation. Both adult and subadult animals markedly increased their feeding rates throughout the course of the winter, with the rates in subadults being generally higher. Nevertheless, both age classes showed a significant decline in body mass throughout the winter averaging 22.3% of the autumn mass in subadult and 9.7% in adult animals. In late winter, an increase in the faecal sand content was found, indicating that the animals were feeding on ground-level plant parts. Measurements of nitrogen content of (1) grass leaves and stems and (2) ground-level sprouts and roots demonstrated a decrease in the food quality of grass leaves and stems from early to late winter. In contrast, the nitrogen content of roots and ground-level sprouts remained stable. It can be speculated that the animals increasingly switched to ground-level plant parts as alternative food in the course of the winter in order to satisfy their needs for a sufficient source of nitrogen.