In a previous article, Reinartz and Reinartz (1981) described the monocot and gymnosperm plants that reach their range limits at the Cedarburg Bog. The bog forest consists primarily of·white cedar (Thuja canadensis) and tamarack (Larix laricina) and includes a string bog plant community, all typical of wetlands further north. The summer fauna also possesses an ecologically northern relict flavor. This is especially true of the most conspicuous vertebrates, the birds. Many bird species found in the bog are more closely associated with the transitional and boreal forests of Canada and northern Wisconsin than with the deciduous forests and fields that predominate in the Field Station area. The surrounding uplands, as well as the bog, also have species of nesting birds that are typical of southeastern Wisconsin, including those often associated with prairie and deciduous forest. While other bogs in southeastern Wisconsin support some species with northern affinities (Beimborn 1970), Cedarburg Bog has the greatest diversity as well as the greatest abundance of such species.
Idzikowski, J.H. 1982. Summer birds reaching the margins of their range at the Cedarburg Bog and the UWM Field Station. 15(1): 1-15.