The shorelines of Lake Ontario is home to a diverse population of flora and fauna with many speices considered rare, threatened or at risk.
One such population is the Bank Swallow which is considered a 'threatened' species in Ontario. Threatened means that the species lives in the wild but is likely to become endangered if steps are not taken to address factors threatening it. In the Province of Ontario, species at threat and their habitat are automatically protected from development.
The bluffs along the shores from East Point to Grey Abbey provide excellent nesting conditions for the bank swallow. The sediment is soft enought to allow for excavation and stable enough to stay intact for the duration of the nesting season.
The significance of the bank swallow population has been documented in this extensive inventory report that was commissioned by the TRCA in February 2012; Scarborough Shoreline Terrestrial Biological Inventory and Assessment
The site holds considerable significance for nesting bank swallows with several hundred nesting pairs throughout the site. Taken as one disparate colony this population constitutes an extremely significant fraction of the regional population for this declining species, a species that is currently on the priority list of candidate species at risk expected to be assessed by the Committee on the Status of Species at Risk in Ontario (COSSARO).
Bank swallows (Riparia riparia, L4) nest here in their hundreds. This species will initiate and maintain colonies in a diverse range of landscapes; however, it is the species’ microhabitat requirement that confers a high degree of habitat dependence (and likewise for its close relative the northern rough-winged swallow, Stelgidopteryx serripennis).
Bank swallows excavate burrows in the selected cliff, bank or bluff, but the condition of the sediment is very important – soft enough to allow excavation but stable enough to maintain for at least the length of the nesting season. Sites are not necessarily re-used in subsequent years and to some extent the use of sites is unpredictable. However, the sheer number of birds involved at the Scarborough Shoreline study area suggests that the bluffs along the shoreline provide excellent nesting conditions for this species.