MARQUETTE — The piping plover may have a new predator to worry about, the common grackle, which has been photographed for the first time eating eggs in a nest of the endangered migratory bird.

“This behavior adds the common grackle to the suite of egg predators and has critical implications for this shorebird species,” according to researchers whose trail camera recorded the attack on the western Lake Michigan shoreline.

The new study comes from scientists at Audubon Great Lakes, the National Audubon Society, the U.S. Fish & Wildlife Service and the U.S. Department of Agriculture’s APHIS Wildlife Service.

U.S. and Canadian conservation groups and public land and wildlife management agencies have been using wire enclosures to protect piping plover nests on the Great Lakes shorelines, including the one where the grackle attack occurred.

Piping plover nests in the Great Lakes and elsewhere were already known to be vulnerable to American crows, herring gulls, ring-billed gulls, common ravens, American mink, raccoons, coyotes and red foxes, the study said.

Michigan has federally designated critical habitat for piping plovers in Alger, Alpena, Benzie, Berrien, Charlevoix, Cheboygan, Chippewa, Delta, Emmet, Iosco, Leelanau, Luce, Mackinac, Manistee, Mason, Muskegon, Oceana, Presque Isle and Schoolcraft counties, and there have been confirmed observations in Bay and Huron counties, according to the state Department of Natural Resources.

The photographed grackle predation took place at Longtail Point, a sandspit on the lower bay of Green Bay, Wisconsin.

The DNR’s Wildlife Division says the Great Lakes population of plovers breeds mainly in Michigan and chooses “open, sparsely vegetated sandy coastal habitats for nesting, rearing young and foraging.” Its nesting sites on Lake Michigan are on sparsely vegetated sand spits and sand beaches.

The department’s announced goal is to have at least 150 breeding pairs in the Great Lakes region for at least five consecutive years, with at least 100 of those pairs in Michigan. That target is below the high point in the late 1800s when there were several hundred breeding pairs in the region.

“Protection of breeding pairs and nest sites from human disturbance and shoreline development is pivotal to successful production of hatchlings) and eventual recovery, the DNR says.

In summer 2024, there were 81 breeding pairs in the region, and 68 nests hatched in the wild, according to Audubon’s Sarah Saunders, a coauthor of the study published in the journal Waterbirds.

Of those nests, 53 were in Michigan, seven in Wisconsin, four in Ontario, two in Illinois and one each in Pennsylvania and New York, Saunders said.

Coyotes were among the main suspects in the 2024 killing of several plover chicks at the same site on Green Bay, but attempts to trap coyotes there were unsuccessful, she said.

The DNR cautions, “The current size of the Great Lakes population still makes it extremely vulnerable to chance demographic and environmental events that could extirpate” — wipe out — “the species from the region.”

The new study said, “As the Great Lakes piping plover population has grown over the last several decades, historically used breeding sites have been recolonized, in part due to management aimed at restoring suitable nesting and foraging habitats.”

Grackles, a type of blackbird, eat primarily seeds but also consume insects, fish, salamanders, frogs and small birds, the study said.

A series of pictures from the trail camera documented a male grackle and a red-winged blackbird entering an enclosure with a plover nest of four eggs in June 2023. Photos captured the grackle feeding on three of the eggs.