The Numerical Response of Avian and Mammalian Predators during a Gradation of the Spruce Budworm

Reversed Impacts by Specialist Parasitoids and Generalist Predators May Explain a Phase Lag in Moth Cycles: A Novel Hypothesis and Preliminary Field Tests

“…at the bottom and early increase phases (e.g. Morris et al 1958, Campbell & Sloan 1977, Holmes et al 1979, Berryman 1987, Elkinton et al 1996. This effect weakens at the late increase and peak phases of the prey cycle due to predator saturation with increasing prey density (Morris et al 1958, Enemar et al 2004.…”

“…Morris et al 1958, Campbell & Sloan 1977, Holmes et al 1979, Berryman 1987, Elkinton et al 1996. This effect weakens at the late increase and peak phases of the prey cycle due to predator saturation with increasing prey density (Morris et al 1958, Enemar et al 2004. This is congruent with the general synoptic model for outbreak insects suggesting that low-density populations are maintained by generalist predators with constrained abilities to respond to increases in the density of their prey (Southwood & Comins 1976).…”

Cross‐scale effects of spruce budworm outbreaks on boreal warblers in eastern Canada

“…From a silvicultural perspective, spruce budworm outbreaks may emulate shelterwood regeneration cuttings in mature stands and thinning operations in pole‐size stands (Baskerville, 1975), and thus contribute to the uneven‐aged stand management regimes associated with higher biodiversity values (Drever et al., 2006). However, if bird community shifts (increased populations of 1 or 2 species) result in competitive disadvantage or exclusion for other species, then budworm outbreaks could be viewed as conservation‐neutral, for example, we found that budworm outbreaks were associated with reduced numbers of Blackburnian and black‐throated green warblers in Quebec and New Brunswick, which may be attributable to the incursion of aggressive species like the bay‐breasted warbler (Morris et al., 1958). Such competitive interactions may form part of the natural repercussions of pulses in food supply and will need to be well understood as forest management regimes strive to emulate natural disturbances.…”

Biodiversity Conservation in Managed Landscapes

“…Similarly, insectivorous bird species are considered to be instrumental in controlling outbreaks of forest insect pests in boreal and deciduous forests in North America and Europe [Morris et al, 1958;Tinbergen, 1960;Campbell and Sloan, 1976;Holmes et al, 1979;Takekawa et al, 1982;Holling, 1988;Maquis and Whelan, 1994].…”