The effect of forest fragmentation on food abundance, nest site habitat, and reproductive success of forest-breeding birds: A study in the Peterborough region of Ontario

he purpose of this study was to determine the effect of local forest cover and the size of remnant hardwood forests on the composition, demography, density, pairing and reproductive success of forest birds. Between 1994 and 1997, two continuous forest sites and 79 different fragments were studied (0-420 ha in core area) in south-central Ontario. Forest-interior bird species showed the greatest reductions in richness and density as the amount of core forest area declined. Significant reductions occurred in Ovenbird density and pairing success with reductions in woodlot core area. This was attributed to lower food abundance and a lack of suitable nest sites in small woodlots. Wood Thrush and Veery were limited in small fragments by food and interior nest sites, while Rose-breasted Grosbeaks and Red-eyed Vireos did not appear to lack nesting or foraging opportunities. For all species nest success was highest in continuous forest, and birds in large fragments were generally more successful than those in small. As small forest fragments were habitat sinks for all species, I recommend the preservation of forests...