This IBA on the Door Peninsula encompasses Toft Point State Natural Area, The Ridges Sanctuary, a nonprofit nature preserve (The Ridges Sanctuary 2007), Bailey?s Harbor Boreal Forest and Wetlands State Natural Area, Moonlight Bay Bedrock Beach State Natural Area, and Mud Lake State Wildlife Area, which also includes Mud Lake State Natural Area. Extensive areas of unbroken forest, coastal wetlands and bays, old growth remnants, and unique dune-swale topography make this area one of the most significant natural areas in the Midwest, if not the entire eastern U.S. Habitat types include boreal forest remnants of white spruce and balsam fir, upland and lowland mixed coniferous-hardwood forest, alder thickets, sedge meadow, and coastal marsh. This site hosts many rare species of plants and animals including the federally endangered Hine?s emerald dragonfly and dwarf lake iris. Uncommon plant species such as bird?s eye primrose, small fringed gentian, and tufted hair grass grow on areas of exposed dolomite bedrock (WDNR 2007a, b, c, d). Thanks to shallow soils and frequent flooding, most of the area has escaped clearing and intensive human land use. Today, the primary goal of land management is conservation, and much of the land is seldom visited except along roads or established trails. Hiking trails are available at The Ridges and at Toft Point, and less-traveled trails and vehicle tracks can be found at the Mud Lake State Wildlife Area and Mud Lake State Natural Area.
The size and strategic position of this IBA make it one of the most significant migratory stopover sites along the western shore of Lake Michigan. Protected wetlands and bays attract waterfowl, and the adjacent wetlands (both open and forested) and uplands are used extensively by migrants, perhaps providing critical shelter and food during severe spring or fall storm events. Priority breeding birds in this IBA include shoreline raptors like Bald Eagle and Osprey, which have become re-established as regular breeders. Unusually high numbers of warblers, including Canada Warbler and Mourning Warbler, also are present; 17 species of warbler breed here in all (Pohlman et al. 2006). Breeding populations of Yellow-bellied Flycatcher, Blue-headed Vireo, Northern Waterthrush, Blackburnian Warbler, Magnolia Warbler, Northern Parula, and other northern species are near the southern edges of their geographic ranges. Coastal wetlands are home to American Bittern and possibly other species of conservation concern, including (recently) Trumpeter Swans. Shorelines are used by Common and Caspian Terns and are one of the few areas in Wisconsin where Common Goldeneye have nested regularly. The habitats at this IBA are among the best remaining examples of Great Lakes coastal forests and wetlands. Educational benefits of the site are evident at The Ridges Sanctuary, where thousands of visitors take part in bird hikes and other programs.
The conservation significance of this area is extremely high (Pohlman et al. 2006). The area has a high degree of protection, but continued development of the surrounding areas in Door County will present ongoing conservation challenges. Deer over-browsing is a threat to forest regeneration and likely is a critical threat to sustaining bird habitats, especially nesting microhabitats in the understory. Invasive species are a threat to the integrity of coastal wetlands, in particular. Management and stewardship should focus on maintaining, restoring, and connecting intact blocks of habitat and controlling invasive and overabundant species. This site would benefit from more intensive property-wide monitoring to better document populations of priority species.