Monarch migration stronghold turns 105

Monarch butterfly on climbing fumitory at St. Martin Island. (U.S. Fish and Wildlife Service photo/Tina Shaw)

Monarch habitat in the middle of Lake Michigan? Yes — today (Feb. 21) marks the 105th birthday of one of our oldest national wildlife refuges and Great Lakes migration routes for migratory birds and other species, like monarchs.

On this day in 1912, President William Howard Taft established Green Bay National Wildlife Refuge, our nation’s 28th refuge and only the second refuge in the Great Lakes Region. Located in Lake Michigan, off the tip of Wisconsin’s Door Peninsula, the refuge started as a mere two-acre island that was originally named Green Bay Reservation. Today, this essential stopover habitat for birds and other migratory species consists of five islands and is framed by two states.

Biologists and land managers have been roughing the waves and extreme weather of Lake Michigan to help colonial nesting waterbirds birds for more than 100 years, but the refuge boasts more than nesting birds. While they started with a small footprint that focused on bird conservation, botanists and other researchers from around the world have come to study the diverse plant life that has persisted here for millennia. Plum Island (325 acres) and Pilot Island (3.7 acres), in Wisconsin, were added to the refuge in 2007. Later in 2015, Rocky Island (10 acres) and part of St. Martin Island (1,260 acres), in Michigan, also grew this remote gem.

Stepping stones across the Great Lakes

The chain of islands running north off of Door County, Wisconsin, up to the southern part of Michigan’s Garden peninsula, act as a set of stepping stones for migratory birds and monarchs to rest and replenish their energy needs with ample supplies of food. The islands are also a geologically unique feature, being part of the Niagara Escarpment, a fault line extending from Niagara Falls through Canada, Michigan, and Wisconsin.

The islands that make up the refuge protect a special ecosystem type called alvar, a limestone covered by a thin soil layer, which is absent on the mainland. Some of the islands also contain northern mesic forest communities that are home to 45 species of concern.

St. Martin Island supports 43 neo-tropical migrant birds and 26 species of greatest conservation need in Michigan. More than 400 plant species, including the dwarf lake iris, a federally-threatened species, have been found here and the island’s broad shallow “flats” offshore are prime areas for spawning fish.

Common sightings in the refuge include, white-tailed deer, snakes, and newts. You’re also likely to see water-loving birds like mergansers, ring-billed gulls, bald eagles, herons, egrets, and pelicans, as well as birds that prefer woodland habitats, like warblers and pileated woodpeckers. If you’re lucky you might see an American redstart or a Caspian tern.

Some of the species of plants found on the refuge have been completely decimated on the mainland, such as Canada yew, a shrubby understory species. Other species of concern found on the refuge include American sea rocket, dune goldenrod, white camas, and climbing fumitory.

Learn more about Green Bay National Wildlife Refuge at https://www.fws.gov/refuge/green_bay/

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