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ABSTRACT. Northern forests are major breeding habitats for several waterfowl and other waterbird species. In Quebec, as in many other areas within the boreal region, clear-cut logging is an important human activity, and it is likely to affect ground-and cavity-nesting species differently. We used Black Duck Joint Venture/Canadian Wildlife Service aerial survey data, together with Quebec digital forest maps, to investigate local, i.e., within 2 km of clear-cut areas, short-term (~ 4 yr) effects of forest harvesting on waterfowl and Common Loon. Our predictions were that clear-cut logging would not affect ground nesters, but would negatively affect pair settling patterns in cavity nesters through nesting habitat disturbance. Our study spanned a 540,000-km² territory in which we considered over 30,000 ha of clear-cut areas that were dispersed into 42 different locations. We controlled for interannual variation in population size by comparing the pre-and post-harvest percentages of potentially hospitable nesting cover disturbed by timber harvesting within a 1-km radius of indicated breeding pairs. Our results suggest that timber harvesting positively influenced local populations of Canada Goose and American Green-winged Teal. No other ground-nesting species showed a significant response. For the cavity-nesting guild and species, we detected no local, shortterm effect of clear-cutting. This result was unexpected because many previous studies of nest-box provisioning reported increased breeding pair densities, indicating that availability of natural holes may limit cavity-nesting duck populations. Moreover, because cavity-nesting ducks are considered among the most vulnerable bird species to forest management, our results are consistent with the hypothesis that boreal bird populations exhibit some resilience to disturbance. This conclusion follows from a study in landscapes where forests were mostly first-growth. It is not evident that it will remain valid following subsequent clear-cutting episodes and long-term forestry.RÉSUMÉ. Les forêts nordiques sont des habitats essentiels pour plusieurs espèces de sauvagine et d'autres oiseaux aquatiques. Au Québec comme dans beaucoup d'autres territoires forestiers boréaux, l'exploitation forestière est une activité humaine importante susceptible d'influencer les espèces de sauvagine nichant au sol différemment de celles nichant en cavité. À partir des données de l'inventaire aérien du Plan conjoint sur le Canard noir-Service canadien de la faune et des cartes écoforestières numériques du Québec, nous avons étudié les effets locaux (à moins de 2 km des aires de coupe) et à court terme (environ 4 ans) de la récolte forestière sur les populations de sauvagine et de Plongeon huard en période de nidification. Nos prédictions étaient que la récolte n'influencerait pas le patron de répartition des couples d'espèces nichant au sol, mais affecterait négativement celui des nicheurs en cavité par une altération de l'habitat de nidification. Notre étude s'est étendue sur un territoire de...

Wetlands of remote forested landscapes of Quebec support numerous species of breeding waterbirds yet species-habitat associations remain poorly quantified. From 1990 to 2005, we conducted systematic helicopter surveys of breeding waterfowl and common loons (Gavia immer) across a 540,000-km 2 forested region of Quebec. Data from this survey were used to investigate local habitat use and selection by waterbirds, based on a wetland classification system derived from digital forestry maps. Detailed indicated-breeding-pair (IBP) distributions were developed for broad aquatic, wetland, and shoreline habitat types. We also estimated selection ratios within groups of similar habitat types. Small (≤8 ha), connected ponds were highly used and selected by five dabbling duck species and by wood duck (Aix sponsa), Canada goose (Branta canadensis), ring-necked duck (Aythya collaris), hooded merganser (Lophodytes cucullatus), common goldeneye (Bucephala clangula), and Barrow's goldeneye (B. islandica). Dabbling duck species, wood duck, and Canada goose made extensive use of streams (25-41% of all IBP). Community organization was mainly driven by openness of aquatic habitat and water movement, i.e., from lentic to lotic habitats. Failure to include streams in waterfowl surveys and habitat mapping could produce biased estimates of wetland habitat use and selection in the boreal forest.

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