Description of Bird Conservation Region 13
The Lower Great Lakes/St. Lawrence Plain covers the low-lying areas to the south of the Canadian Shield and north of various highland systems in the United States. In addition to important lakeshore habitats and associated wetlands, this region was originally covered with a mixture of oak-hickory, northern hardwood, and mixed-coniferous forests. Very little of the forests remain today due primarily to agricultural conversion. The highest priority bird in remnant forests is the Cerulean Warbler. Because of agriculture, this is now the largest and most important area of grassland in the Northeast, providing habitat for such species as Henslow's Sparrow and Bobolink. Agricultural abandonment may temporarily favor shrub-nesting species, such as Golden-winged Warbler and American Woodcock, but increasingly, agricultural land is being lost to urbanization. This physiographic area also is extremely important to stopover migrants, attracting some of the largest concentrations of migrant passerines, hawks, shorebirds, and waterbirds in eastern North America. Much of these concentrations are along threatened lakeshore habitats.