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Refuge Units

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The Detroit River International Wildlife Refuge is the only International Wildlife Refuge in North America.  The refuge includes islands, coastal wetlands, marshes, shoals, and waterfront lands along 48 miles of Detroit River and Western Lake Erie shorelines.  

  • Mud Island

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    Mud Island is the northernmost island in the Refuge’s acquisition boundary.  The 18.5 acre island and its surrounding shoals were donated to the National Wildlife Refuge System in 2001. Approximately 75 percent of Mud Island is forested with more than 20 years growth of deciduous hardwood trees, dominated by red maple, silver maple, white ash, cottonwood and willow, creating important stopover habitat for neotropical migrant birds during spring and fall. Warbling vireos are can often be heard in the breeding season from the tops of the cottonwoods.   

    The 71.5 acres of shallow shoals surrounding the island are on average, 2 feet in depth, and support aquatic species such as wild celery.  Between the mainland (City of Ecorse) and the island is the Ecorse Channel; a popular fishing location for local residents. The aquatic plants present here are diverse, and dabbling ducks and swans (tundra and mute) are commonly seen in abundance feeding on them. A deep shipping channel exists east of the island with an expansive wild celery bed mid-stream that connects to Grassy Island.

    Mud Island is closed to the public.
     
  • Grassy Island

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    Although Grassy Island is constructed of contaminated dredge material surrounded by dikes, its surrounding waters are biologically rich. At least 30 species of fish are found here, including rock bass, yellow perch, and emerald shiner.  Numerous aquatic plants such as muskgrass, pondweed species and  especially wild celery are abundant. Diverse rock structure and current speeds create good fish spawning and nursery habitat. 

    The uplands of the island are dominated by early successional tree species such as eastern cottonwood, box elder, staghorn sumac, and willow with heavy infestation of some invasive plants. Albeit far from pristine, the island has demonstrated high use by neotropical migrant birds during spring and fall.
    Grassy Island is closed to the public.

    View additional information about Grassy Island. 

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  • Calf Island

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    A naturally formed island in the lower Trenton Channel, the 11-acre Calf Island provides important stopover habitat for migratory songbirds. Each end of the island is flanked by high quality wild celery beds important for fish and waterfowl. The forest is reflective of intensive farming and development with ruins of old structures, lilac bushes, and decades-old debris. On the north side of the island, an emergent wetland is present, surrounded by willows.  A number of mature red and swamp white oaks also exist on the island. 

    With the exception of hunting, public use activity on the island is prohibited at this time.

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  • Gibraltar Bay Unit

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    Much of the upland of Gibraltar Bay Unit was once used as a former D-51 Nike Missile site.  The site was home to 30 anti-aircraft Nike Ajax missiles, 12 launchers, and two radar towers between 1955 and 1963. The embankment to Gibraltar continues to protect the former launcher area. After the site-clean-up was complete in 1998, the unit was planted to grassland habitat. A shoreline habitat project was completed in the mid-2000s introducing a number of native plants. 

    Water flows through the embayment from the east side of Grosse Ile, and its aquatic plant community is diverse. Emergent species are threesquare, arrowhead, pickerelweed, flowering rush, and American lotus and emergent species include pondweeds, wildcelery, muskgrass, and others. This bay is important for bass, pike, and long-nose gar.

    The Gibraltar Bay Unit is open on a semi-regular basis May through October. Click to view a schedule of open houses and other events at the unit hosted by the Grosse Ile Nature and Land Conservancy. 

  • Sugar Island

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    Situated on the southeast end of Grosse Ile, just one mile from Bob-lo Island and 1.5 miles from Amherstburg, Ontario, the 30-acre Sugar Island is fascinating from a fish and wildlife perspective. The state-endangered channel darter is found around the island’s quick currents and rocky substrate. The only two significant sand beaches on the Michigan side exist on the east and west side of the island. These beaches are locally unique with threesquare and rufous bulrush at the ever-changing water’s edge. Willows, silverweed, milkweeds, and others can be found in the island’s sandy environment. The forest is particularly diverse with understories rich in native grasses and sedges, and a stand of young sugar maples.

    With the exception of hunting, public use activity on the island is prohibited at this time. 

    Learn more about Sugar Island

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  • Refuge Gateway Property

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    The Refuge Gateway property sits adjacent to the Refuge's Humbug Marsh Unit in Trenton, Michigan.  This 44-acre industrial brownfield was the home of a Chrysler automotive plant until 1990; Today, it is owned by Wayne County.  In 2006, a Master Plan developed by the U.S. Fish and Wildlife Service, Wayne County, and other vested partners was adopted for the site to serve as a blueprint for the cleanup and restoration work underway. 

    Future plans for the property include a new Visitor Center for the Detroit River International Wildlife Refuge, a world-class boat dock and fishing pier, greenway trails, and native habitats. 

    Learn more about the Refuge Gateway property. 

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  • Humbug Marsh Unit

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    The Humbug Marsh Unit is a major part of the Conservation Crescent of the lower Detroit River (including Humbug mainland, Calf Island, Gibraltar Bay, and Sugar Island), and a hotspot of biodiversity in this urban landscape. Adjacent to the future Refuge Gateway to the north, Humbug is mostly forested with areas that were clear-cut in December 1998. Humbug Marsh was designated as Michigan's first "Wetland of International Importance" by the Ramsar Convention on Wetlands in 2010.  

    This mesic flatwoods is underlain by poorly drained stiff clay, ponding water for prolonged periods, but with low moisture availability at times. Shagbark hickories, oaks, ash and elm dominate in a mosaicked fashion across the unit with the more aggressive rough-leaved dogwood and goldenrod species present in early successional habitats. The coastal wetland is dominated by bulrushes, native and naturalized grasses, cattail, and Phragmites. An ever-changing habitat condition based on Great Lake water levels, Humbug is a major repository of species and preservation of ecosystem processes.   

    With the exception of hunting, public use activity on Humbug Island is prohibited at this time. The mainland portion of the unit is open on a semi-regular basis April through October. To view a schedule of open houses and other events at Humbug Marsh and the Refuge Gateway, click here. 

    Learn more about the Humbug Marsh Unit of the Detroit River International Wildlife Refuge. 

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  • Gibraltar Wetlands Unit

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    A contiguous block of 360 acres of habitat is rare in an urban area. Especially rare is a natural area this size within a half-mile of the 410-acre Humbug Marsh Unit. Even rarer, still, is the diversity of habitat within this unit. Significant to the local landscape, marsh creek flows through the eastern portion of the unit fringed by river bulrush and a blue-joint dominated plant zone. Stands of mature black walnut and pin oak exist along with large swaths of dogwood and buckthorn shrub. The large wetland mitigation on the south half of the wetlands contains wet reed-canary grass habitat and rich green ash swamp.

    The Gibraltar Wetlands Unit is situated adjacent to the Gibraltar Carlson High School and is frequently used by the school's Wetlands Science classes via special use permit. This unit is closed to the public. 

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  • Lake Erie Metropark

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    Lake Erie Metropark is managed in cooperation with the Huron-Clinton Metropolitan Authority.  The habitats of the metropark are a mix wetlands and early-successional forest.

    Learn more about Lake Erie Metropark. 

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  • Strong Unit

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    Another unit highly influenced by Lake Erie water levels, the Strong Unit contains emergent wetland, a former shoreline ridge of trees, and wet meadow communities. Unique to this unit is the abundance of blue-joint grass, shoreline sedge, rose mallow, and swamp milkweed. The unit's meadows are surrounded by willows, dogwoods, and mature oaks, creating an important diversity of habitat for native species. Thirty-six acres are currently in use for agriculture. 

    With the exception of hunting, public use activity on the Strong Unit is prohibited at this time. 

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  • Brancheau Unit

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    A 67-acre restored marsh located in Monroe County, the Brancheau Unit was added to the Refuge in 2003. Most of the wetlands at the unit are diked, giving Refuge personnel the ability to manipulate water levels. A high abundance of sora, marsh wren, moorhens, coots and pied-billed grebes use the unit for nesting. Least bittern can be heard calling here and is periodically seen when they rise above the cattails. Fall at the Brancheau Unit proved successful for hunter taking teal, gadwall, wood duck, and mallard. Recently, an additional 28 acres were acquired and is currently in agricultural production.

    With the exception of hunting, public use activity on the Brancheau Unit is prohibited at this time. 

    Learn more about the Brancheau Unit of the Detroit River International Wildlife Refuge. 

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  • Fix Unit

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    Much of the Fix Unit is in agricultural production until habitat restoration funding and plans are in place. However, the eastern section has a rich meadow community of blue-joint and willow/dogwood shrub, and the Refuge has begun control of Phragmites infestations.  This unit is adjacent to the Michigan Nature Association’s Swan Creek Plant Preserve. 

    With the exception of hunting, public use activity on the Fix Unit is prohibited at this time. 

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  • Lagoona Beach Unit

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    The Lagoona Beach Unit is managed cooperatively by the Refuge in partnership with DTE Energy. Its wetlands are dominated by American lotus, cattail, and Phragmites. 

    The Lagoona Beach Unit is closed to the public.

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  • Ford Marsh Unit

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    Ford Marsh is a contiguous 180 acres of wetland adjacent to the River Raisin, Lake Erie, and habitat at Sterling State Park – a significantly large wetland on the western Lake Erie landscape. Currently dominated by white water lily and approximately 3 feet of water, hundreds of waterfowl have been seen including shovelers, teal, American black ducks, and gadwall. The only hydrological connection to Lake Erie is through a 36-inch overflow pipe periodically connected to the Clearwater Canal to the north.

    The Ford Marsh Unit is closed to the public.

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  • Plum Creek Bay Unit

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    The Plum Creek Bay Unit is directly influenced by wind events that dictate the amount of water in the bay. West winds blow water out, while east winds flood the bay. Plum Creek flows into this bay in the northwest corner through a number of springs on the south side. 

    Refuge staff have begun treatment of Phragmites throughout the unit to promote many species of wetland plants found here. Sora and Virginia rail are particularly abundant during nesting and migration. Shorebirds like least and semipalmated sandpipers, yellowlegs, killdeer, and herons and egrets are frequently seen in the mudflats and shallows of this unit.

    With the exception of hunting, public use activity on the Plum Creek Bay Unit is prohibited at this time

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  • Lady of the Lake Unit

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    This unit is under a cooperative management agreement with Consumers Energy and is 49 acres on 680 meters of western Lake Erie shore frontage situated next to the J.R. Whiting Power Plant. This unit is connected to adjacent wetlands owned by Consumers Energy not under the cooperative agreement. The cooperatively managed wetland is connected to Lake Erie via a 12-inch overflow pipe discharging into the LaPointe Drain Channel and subsequently, Lake Erie with a flap gate to prevent water from entering the wetland from the Lake. The Lake Erie side of the wetland is a bermed trail with a sand beach worked by wave action on the east side. Unhardened sand beaches are rare along the western Lake Erie basin. The scarcity of the water/beach interface in this region intuitively protects important species and ecosystem processes.

    The Lady of the Lake Unit is closed to the public.

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  • Holloway Unit

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    The Holloway Unit is a slice (in terms of the surrounding landscape) of the Erie Marsh and Erie State Game Area. Much of it is covered in American lotus with recent water levels. The uplands contains a mix of shrub and grassland habitat.

    The Holloway Unit is closed to the public.

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  • Erie Marsh Preserve

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    A cooperative unit with The Nature Conservancy, the preserve and adjacent Erie State Game Area is one of the largest contiguous coastal marshes along the western basin, and very significant in preserving a vast array of the region’s flora and fauna.

    The Erie Marsh Preserve is closed to the public.

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  • Gard Island

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    Gard Island is managed cooperatively with the University of Toledo.  The 19-acre island is located within North Maumee Bay.

    Gard Island is closed to the public.

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Page Photo Credits — Grassy Island © Derek Van Aken, All photos courtesy of USFWS unless otherwise noted.
Last Updated: Oct 31, 2013
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