Selective feeding behaviour in roe deer: learning and recognition of plant species, and effects on the development of repellents.
The development of feeding behaviour and recognition of preferred and non-preferred plant species were studied in 9 roe deer (Capreolus capreolus) fawns separated from their mothers 3 days after birth. From age 15 days to 1.5 months they were offered species always avoided by roe deer (Arum italicum, A. maculatum and Euphorbia amygdaloides), species normally avoided but which could be eaten occasionally (Primula veris, Ajuga reptans and Viburnum lantana) and preferred species (Carpinus betulus and Acer monspessulanum). Feeding behaviour of the fawns was compared with that of 8 adults living in a forested enclosure. Fawns displayed selectivity towards the different plant species from their first contact, probably in response to taste. Thereafter, consumption of the 2 preferred species rapidly increased, while use of the others remained at very low levels. Fawn selectivity was similar to that of the adults from the third contact with the plant species (before they were one month old). This learning processes appeared to be based on the association between effects of eating the different plant species (satiation or illness) and taste and smell. Therefore, an effective repellent must have a taste and smell associated with avoided plants, as well the same effects on ingestion.