Taste Responses of Deer to Browse Extracts, Organic Acids, and Odors

Abstract

The response of black-tailed deer (Odocoileus hemionus) to certain browse extracts, non- volatile organic acids, and two odoriferous compounds was determined by use of the two-choice pref- erence test method. The browse extracts and acids were supplied in water solutions and compared with the consumption of tap water. Deer were separated by sex during the experiments. For bucks, bitterbrush (Purshia tridentata) extract was the only extract preferred over all concentrations offered, but bucks showed a moderate to strong preference for all other browse extracts (water extracts of red alder (Alnus rubra), cascara buckthorn (Rhamnus purshiana), Douglas fir (Pseudotsuga menziesii), western hemlock (Tsuga heterophylla), ethanol extract of Douglas fir) at some concentrations. For does, the Douglas fir water extract and bitterbrush extract were preferred at all concentrations offered. Bucks showed a strong preference for cascara at the lowest level, but does generally rejected it except at the highest concen- tration at which a strong preference was demonstrated. Does also showed a somewhat stronger pref- erence for western hemlock extract over the total range of concentrations used. Marked sex differences were shown for the organic acids. Bucks clearly showed a strong preference for the intermediate con- centrations of malic acid and weak to moderate preferences for succinic and citric acids. Results with quinic were more variable. Does did not show preference for any of the acid solutions and, with few exceptions, they showed a weak to strong rejection at concentrations that were likely to be preferred by bucks. Two odoriferous materials-butyric acid (BA) and putrified salmon extract (PFE)-were tested by placing patches above the fluid level inside the containers used for preference testing. Solutions of malic acid and water extracts of western hemlock and Douglas fir and the ethanol extract of Douglas fir were used. Strong sex differences were noted. With the malic acid solution, BA caused a marked reduc- tion of intake by bucks but a marked increase for does. BA also caused a marked reduction of ethanol extract of Douglas fir and reduced intake of western hemlock by does, but caused only minor changes in other comparisons. PFE caused a marked reduction of water and ethanol extracts of Douglas fir by bucks, but had no appreciable effect on consumption by does. In conclusion, data clearly indicate that sex may have a pronounced effect on taste and odor response of black-tailed deer.