Herring and Ring-billed Gulls feeding in the algae mat at Montrose Beach (click to see the larger version)

The title of this post sounds like the title of a horror or monster movie — “Return of the Green Gunk!” On December 14 I was pleasantly surprised to find an extensive algae* mat at the east end of Montrose Beach. This algae mat developed when a powerful early winter storm churned up Lake Michigan and dumped large amounts of the stuff on the beach. I also noticed a group of Herring and Ring-billed Gulls picking through the algae for food. From what I could tell, and from what I’ve seen in the past, the gulls were hunting crayfish that washed in with the algae. Why does this matter? Because groups of active, feeding gulls attract more gulls that could include something unusual. Now that winter is here, there are multiple, possible rare gulls to consider. The algae could also attract a rare shorebird like a Purple Sandpiper or Red Phalarope. So if you venture out to Montrose this winter don’t forget to check the beach, and if there’s an algae mat, check it too. Once the beach gets covered in ice the algae mat won’t be accessible to gulls and shorebirds.

Only a birder gets excited about algae mats, right?