CHANGES IN A FOREST BIRD COMMUNITY DURING AN OUTBREAK CYCLE OF THE SPRUCE BUDWORM IN

We report here changes in the forest bird community of a 10.4 ha study plot located in boreal mixedwood forest of northern Ontario, Canada, between 1966 and 1998. During this period, the region was subject to a severe outbreak of the spruce budworm (Choristoneura fumiferana). Overall, community response to increasing budworm prevalence was positive, although response pattern differed among species. All bird species that increased in population size did so during the increasing phase of the budworm cycle. By the time the budworm outbreak reached its peak in 1989-1990, both in terms of budworm density and defoliation, bird numbers had already been declining for five or more years, suggesting that the advantages conferred by a superabundant food supply were offset by negative effects on habitat.