Effects of monoterpene odors on food selection by red deer calves (Cervus elaphus)

The response of red deer calves (Cervus elaphus) to the odors of Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus conforta) needles and five monoterpene constituents of their essential oils was measured by simple two-choice feeding trials. All odors were significantly rejected (P < 0.05) except Sitka spruce and lodgepole pine by females and Sitka spruce and alpha-terpineol by males. Females had a stronger dislike of all odors except lodgepole pine than males. Rejection of monoterpene odors weakened slightly with time. A strong logarithmic relationship between the strength of the rejection response and vapor pressure of the compounds tested suggested that the odors were rejected on the basis of concentration rather than quality.