JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. This content downloaded from 132.239.Abstract: A lynx (Lynx canadensis) study was conducted in central Alberta in 1964-68. Population densities on 57 square miles in winter decreased from 11 in 196>6S to 3 in 1966-67, then increased to 9 in 1967-68. The winter diet was comprised of 76 percent snowshoe hare ( Lepus americanus), 9 percent ruffed grouse (Bonasa umbellus), 3 percent red squirrel ( Tamiasciutus hudsonicus), 10 percent carrion, and other less important items. The relative importance of the major food items did not change significantly between years, but use of carrion was higher in 196S67 than in the previous two winters. Daily food requirements in winter were 600 and 400 grams for adult and juvenile lynxes, respeotively. From December through MarcAh, lynxes removed six, six, two, and three percent of the December hare population; they accounted for 10, 24, 8, and 37 percent of the December to April decline in hare numbers in 1964-65 through 1967-68, respectively. Lynxes removed less than six, two, one, and two percent of the fall ruffed grouse population during these same winters. Between one and two percent of the fall red squirrel population was taken by lynxes over winter. Kittens were produced in all years, but only those born in 1967 survived through their first winter. Ages of autopsied lynxes also indicated that no young were added to the population in 196>66-the years of lowest hare numbers. Thus, annual productivity of lynxes appears to be direcKy related to abundance of snowshoe hares. We believe that some critical minimum density of hares is necessary for female lynxes to raise kittens.Abstract: A lynx (Lynx canadensis) study was conducted in central Alberta in 1964-68. Population densities on 57 square miles in winter decreased from 11 in 196>6S to 3 in 1966-67, then increased to 9 in 1967-68. The winter diet was comprised of 76 percent snowshoe hare ( Lepus americanus), 9 percent ruffed grouse (Bonasa umbellus), 3 percent red squirrel ( Tamiasciutus hudsonicus), 10 percent carrion, and other less important items. The relative importance of the major food items did not change significantly between years, but use of carrion was higher in 196S67 than in the previous two winters. Daily food requirements in winter were 600 and 400 grams for adult and juvenile lynxes, respeotively. From December through MarcAh, lynxes removed six, six, two, and three percent of the December hare population; they accounted for 10, 24, 8, and 37 percent of the December to April decline in hare numbers in 1964-65 through 1967-68, respectively. Lynxes removed less than six, two, one, and two percent of the fall ruffed grouse population during these same winters. Between one and two ...