"Isle Royale wolves feed almost exclusively on moose and beaver (Castor canadensis). Prey reached peak levels of 2.5 moose/km2 and 0.6 beaver colonies/km2 in 1969 and 1974, respectively; by the late 1970’s prey declined to 1 moose/km2 and 0.2 beaver colonies/km2."(89)

"A dramatic wolf decline occurred in 1980-1982, when population size dropped from 50 to 14 wolves. One major pack, probably the Southwest pack, disappeared completely, and all packs were reduced greatly."(92)

"From December to April, moose constituted virtually the only prey for Isle Royale wolves. During the open-water period, beavers were killed frequently, but more than 80% of prey biomass in summer was derived from moose."(92)

"After a lag, wolf density followed trends in food supply (Fig. 4). Correlations between moose mortality and wolf density in the same and subsequent years suggest that the length of this lag was about 2-3 years (same year, r2=0.61; 1-year lag, r2=0.74; 2-year lag, r2=0.83; 3-year lag, r2=0.81; 4-year lag, r2=0.44)."(93)

"From 1975-1980 to 1981-1982, average core-pack size dropped from 9.5 (SE=0.77) to 4.7 (SE=1.02). This decline was correlated with increased dispersal, evidenced by a growing proportion of single wolves in the population (Fig. 5)."(96)

"Throughout the late 1970’s, wolf density exceeded 80 wolves/1,000 km2, and the 1980 peak of 92 wolves/1,000 km2 represents the highest density recorded for wild wolves. This tends to refute the notion that wolf social behavior intrinsically limits wolf density to a maximum of 38/1,000 km2 (Pimlott 1967; Woolpy 1968). It is clear that the only limits to wolf density are those ultimately imposed by food supply…. As food supply expanded in the early 1970’s, wolf pack territories shrank and dispersal was low, leading to a proliferation of large wolf packs. By the early 1980’s, declining food supply resulting from progressive culling of a reduced moose population, resulted in territorial trespassing, interpack violence, and increased dispersal, ultimately producing fewer packs of smaller size, as also found in Minnesota (Mech 1977b, 1986; Mech and Karns 1977)."(97)

"The behavioral responses of wolves to increased then decreased food supply were not symmetrical. The increase phase was accommodated gradually, but responses to the food decline, especially territory enlargement, were abrupt. Extreme response to food shortage, exemplified by trespassing and interpack violence, seemed to be delayed as long as possible."(97)

"Such delays in response to delays in food declines are ecologically significant, in that high wolf density can be maintained for several years in spite of a declining prey base. Prey populations thus may be held at low levels by predation for many years (Mech and Karns 1977; Nelson and Mech 1981). Where man also hunts the same prey, this may exacerbate management conflicts brought on by low prey density (Gasaway et al. 1983). In theoretical models, such lags in population responses also may produce cyclicity in predator-prey systems (May, 1981; Peterson et al., 1984b)."(97)