Canada warbler (Wilsonia canadensis) breeding ecology in young forest stands compared to a red maple (Acer rubrum) swamp

Abstract

Abstract Individuals within a species occur in different habitat types often with differences in reproductive output. The Canada warbler (Wilsonia canadensis) is an example of such a species as it occurs in several different types of forest habitats, including clear-cuts regenerating after timber harvest and stands of varying ages with dense subcanopy layers. We examined whether Canada warbler breeding ecology differed between a red maple (Acer rubrum) swamp with a thick, naturally-occurring understory and a 20-year-old partial cut with low retention. We mapped male territories on each plot in 2005 and 2006 to determine differences in habitat, territory size, site fidelity, and reproductive success. The results showed little difference in most vegetative characteristics. Overall stem density, number of song perches, and canopy height were similar for both plots. However, we observed differences in species composition, size class of shrubs and trees, and moss ground cover between the two forest types. We also found that individual males used 40–50% less area in the red maple swamp compared to the second-growth plot. These differences did not appear to influence site fidelity or the proportion of males fledging at least one young, measures that were relatively high on both plots. The results of this study are significant for Canada warbler conservation because they demonstrate that suitable habitats for the species can be created through specific harvest strategies. Such timber management strategies may help to reverse the significant decline the species has experienced over the past 40 years in the northeastern United States.