BIRDS
Daniel F. Brunton
BIODIVERSITY CHANGE
With the end of the Wisconsin deglaciation in this area ca. 13,000 - 12,000 years BP (Dyke and Prest 1987a), subarctic/ boreal conditions dominated upland areas of the Mixedwood Plains Ecozone. This condition continued until ca. 10,000 years BP (McAndrews et al. 1987). The ecozone was part of a huge, transcontinental area of boreal/subarctic habitat dominated by extensive northern coniferous forest, peatland and early successional hardwood forest cover. Extensive boreal grasslands extended across at least the Great Lakes portion of the ecozone towards the end of this period (Catling and Brownell 1995). For much of the period (ca. 11,000 - 9,500 years BP) virtually all of the area east of the Frontenac Axis was inundated by the post-glacial marine incursion known as the Champlain Sea (Dyke and Prest 1987b). It filled the massive bedrock depression which had been created by the weight of the glacial ice. Bird species breeding in the ecozone at that time would have reflected the boreal/subarctic (maritime ?) nature of the environment and likely included such species as Arctic Tern, Willow Ptarmigan, Common Eider, Great Gray Owl (Fig.B-1), Common Redpoll and numerous species of shorebirds.
With isostatic rebound the rising earth surface reduced the Champlain Sea to a shallow, freshwater water body (Lake Lampsilis) as southern hardwood and mixed wood habitat spread from southern refugia into the lower Great Lakes area ca. 9,000 years BP. Subsequent vegetation and faunal recolonization of the ecozone was largely from the south and southwest (Appalachian and Mississippi Valley regions).
Prairie and savannah flora and fauna invaded from the southwest during the warmer, drier hypsithermal period which dominated eastern Canada and the Great Lakes region between 7,000 and 4,000 years BP. The intrusion of western biota occurred in a narrow band called the "Prairie Peninsula" (Catling et al. 1992) extending eastward north of Lake Erie into the area north of central Lake Ontario. Birds which inhabit(ed) that range and which may have colonized the Mixed Wood Ecozone at that time include(d) Bobwhite, Wild Turkey, Red-headed Woodpecker and Loggerhead Shrike.
Habitats transitional between the boreal/subarctic environment of the early post-glacial period and the deciduous and mixed forest habitats of the hysithemal period, became established as the climate cooled. Contemporary conditions and habitats were established by ca. 3,500 years B.P., (McAndrews et al. 1987).