Summer diet of two white-tailed deer, Odocoileus virginianus, populations living at low and high density in Southern Quebec

摘要

We investigated summer diets of two White-tailed Deer (Odocoileus virginianus) populations through rumen content analyses. Samples from 93 deer were collected in a low density, LD (1 deer/km(2)) and a high density, HD (14 deer/km(2)) area of southern Quebec during the growing seasons of 1997 and 1998. Availability of preferred forage in forests was greater in LD than in HD, whereas agriculture covered a larger proportion of the area in HD than LD. Rumen composition differed between the two populations. Deer from HD consumed less forbs and leaves of shrubs and trees than did LD deer, whereas they consumed more fruits, grasses and farm crops. The rarity in HD rumens of food items common in LD, as well as in many parts of the White-tailed Deer range (i.e., Lilliacae), indicated that deer could not compensate for the rarity of preferred forest forage by increasing foraging time and had to feed on cultivated crops. Rumen contents of LD deer had a higher level of cell solubles and lignin, which reflected their greater reliance on quality forage growing in forests. Feeding habits and forage quality can explain why deer body size decreased in HD between the 1970s and 1990s whereas LD deer remained large.