A Common Grackle (Quiscalus quiscula) was observed consuming eggs from an exclosed (protected) Great Lakes Piping Plover (Charadrius melodus) nest in the lower bay of Green Bay, Lake Michigan in Wisconsin, USA during June 2023. The observation, captured by a trail camera, is the first photographic documentation of grackle predation in any of the three Piping Plover breeding populations. This behavior adds Common Grackle to the suite of egg predators and has critical implications for this shorebird species, particularly in the Great Lakes region where Piping Plover is listed as federally endangered and Common Grackles are relatively abundant. Given that current nest protection efforts rely on exclosures with openings that enable access by grackles, we recommend (1) identification of Piping Plover nesting locations across the Great Lakes region that are frequently used by Common Grackle, and (2) subsequent alteration of exclosure use (e.g., omission to prevent cueing by grackles or possible structural modification to prevent access) and/or habitat or predator management at locations where grackles are particularly problematic. In addition, increased deployment of trail cameras at Great Lakes sites will help elucidate the extent to which Common Grackle predation of Piping Plover nests is a population-wide threat.