Songbird diversity and movement in upland and riparian habitats in the boreal mixedwood forest of northeastern Ontario

Abstract

Little is known about the importance of riparian areas in supporting avifaunal diversity in the boreal mixedwood forest, especially outside of the breeding season. Bird populations were sampled by mist netting 18 upland and 18 riparian sites along six streams in a forested region of northeastern Ontario. Riparian sites generally had more variable vegetation than upland sites. Some riparian sites formed distinctive habitats, while others were structurally and compositionally similar to upland sites. During spring and fall migration, there was no significant difference in bird abundance or species richness between riparian and upland habitats. During the breeding period, riparian areas had greater avian species richness and abundance and more insects than upland forests, suggesting that birds were selecting these habitats because they contain more food. More birds were captured in nets placed perpendicular to the stream than parallel during the breeding and fall migration periods, suggesting that riparian areas may function as movement corridors. A greater understanding of the importance of riparian habitats to songbird communities is needed if we are to maximize the effectiveness of these regions for conserving avian biodiversity in the boreal mixedwood forest.

Passerine Breeding and Post-Fledgling Habitat Use in Riparian and Upland Temperate Forests of the American Midwest

“…The first posits that dispersal is driven by the higher availability of food resources (Rappole and Ballard 1987, Anders et al 1998, Vitz and Rodewald 2007. Studies have found both higher fruit abundance and insect biomass in riparian forests during the summer and fall (Vega Rivera et al 1998, Iwata et al 2003, Mosley et al 2006. Such protein-rich arthropod sources are of great importance for both growing juveniles and adults molting and building up fat reserves in anticipation of fall migration (Vega Rivera et al 1998).…”

Environmental Services Provided from Riparian Forests in the Nordic Countries

“…RF are found to be utilised more frequently by songbirds than upland forests, both during the breeding and during the fall migration periods (e.g. Mosley et al 2006). As an example, neotropical migrant songbirds were captured more frequently in mist nets located perpendicular to the streams during both breeding and fall migration.…”

Breeding Birds in Riparian and Upland Dry Forests of the Cascade Range

“…Recommended buffers for other forested areas within Washington State are 61 m wide on each side of the stream (Washington Department of Fish and Wildlife 1996). Those buffer widths would include a substantial area of upland forest, in many cases !50% of the buffer width on these third-and fourth-order streams, which also would accommodate a corridor function for upland species (Machtans et al 1996, Wiebe and Martin 1998, Mosley et al 2006. Most upland species also used the narrow riparian zone, so a corridor function would not be solely dependent on inclusion of upland forests.…”