Dietary costs and benefits of lakeshore vs aggregate pit breeding in Bank Swallows (Riparia riparia)
Bank Swallows (Riparia riparia), a threatened species in Ontario, breed primarily in either banks at lakeshores or at exposed surfaces in man-made aggregate pits that occur with and without waterbodies. Pits are suspected to be ecological traps for this species but the relative trade-offs in nesting at pits vs. natural sites are poorly known. Availability of aquatic emergent insects is expected to be highest at lakeshore colonies with associated nutritional benefits including Omega-3 fatty acids. However, Bank Swallows may experience differential mercury exposure depending on habitat use. Potential difference in dietary quality among sites may directly influence juvenile body condition. This study seeks to compare these breeding habitats to evaluate dietary differences. This information will be important for management decisions related to the use of pits by this species and conservation of suitable nesting habitats.