Gull on Lake Detroit

This morning, 3-23-10, there is a large gull on Lake Detroit south of Lake Avenue.  It was standing near some American Crow and was larger than the crow.  It has a white head, gray mantle and black primaries.  Judging by the size and overall appearance I'm guessing it is a Herring Gull, but can not say for sure.  Anybody else care to comment?