First Seagulls, Now Loons

The Record Eagle reported today on the ongoing observations of dead birds along the shore of Lake Michigan, in the National Lakeshore. The birds are dying from botulism, but their food sources are being disrupted as an indirect result of the proliferation of zebra mussels, an invasive specie, in Lake Michigan. Ken Hyde, a National Park Service biologist, theorizes that:

Sediments that contain the bacteria are being filtered by non-native Zebra Mussels, thus concentrating the Botulism in the mussels. The mussels are then eaten by non-native Round Gobies, which in turn are consumed by the affected birds.

At first we saw seagulls dead on the beach, but the die-off is also affecting grebes, mergansers, and loons. If there is a bright spot in the situation, it may be that park visitors are now much more likely to follow the rules and keep their dogs on the leash.