Celebrating the future and appreciating the past
Great Lakes oasis turns 105
January 9, 2018
Caspian terns at Gravel Island National Wildlife Refuge. Photo by USFWS.
Today marks the 105th birthday of a small refuge in the middle of Lake Michigan. For more than a century, we have been managing this remote refuge out of the limelight to protect an oasis for resident and migratory birds. Gravel Island National Wildlife Refuge is made up of 23-acre Spider Island and four-acre Gravel Island and is located off the tip of Wisconsin’s Door Peninsula in Lake Michigan. In honor of their birthday, let’s take some time to learn about what makes this place so special.
Gravel Island National Wildlife Refuge is part of a geological feature known as the Niagara Escarpment, which is a fault line that runs from Niagara Falls through Canada, Michigan’s Garden Peninsula, down the Door County Peninsula through Wisconsin and ending at Horicon National Wildlife Refuge. The limestone and dolomite rocks that make up the base of this remote refuge formed from compacted sediments of marine life that were deposited more than 500 million years ago, when the area was covered by an ancient ocean.
Set aside by Executive Order in 1913 as a preserve and breeding ground for native birds, these islands have been a hub for waterbird population dynamics researchers for many years. Today, the refuge offers rare opportunities to study Great Lakes biology without human disturbance. Recent studies are focused on understanding double-crested cormorants and developing habitat monitoring protocols.
The islands are a valuable resting, feeding and nesting habitat. Gravel Island National Wildlife Refuge and the nearby Hog Island, make up the Wisconsin Islands Wilderness Area. At 29 acres, it’s one of the smallest wilderness areas in the country and Wisconsin's only congressionally mandated wilderness area.
Isolation is important here
Pectoral sandpipers in flight. Photo by USFWS.
Combined, these islands host more than a dozen species of management concern. Because of this and the fact that colonial nesting birds are sensitive to human disturbance, the refuge is closed to visitors. To minimize disturbance to the birds and their young, we ask that you keep a quarter-mile distance from these islands.
The islands also support the largest Caspian tern colony in the Great Lakes Region. Caspian terns are the world’s largest terns. These stepping stones across Lake Michigan also provide needed resting and feeding habitat for a large variety of migrating shorebirds like black-bellied, piping and semipalmated plovers, killdeer, greater and lesser yellowlegs, upland, least and pectoral sandpipers, dunlins, red knots, sanderlings and ruddy turnstones.
This part of Lake Michigan has a rich maritime history, with all sorts of old shipwrecks near Death’s Door Passage. While Gravel Island is closed to visitation, you can plan your trip to Plum Island as an alternative. Part of Green Bay National Wildlife Refuge, Friends of Plum and Pilot Island help to host interpretive talks and tours in the summer months. You can also visit Newport State Park to learn more about local ecology.