Three Terns

Crossing the Calcasieu Ship Channel on the ferry in Cameron today, I had a good chance to compare the winter plumages of three small tern species.  The Common Tern, above, is usually hard to find at this time of year, but there were at least a couple there today.  Winter Common Terns generally look like this bird, with a darker patch on the front edge of the upperwing, and a cap that leaves the forehead white but meets around the back.

Seen from beneath, the wingtips of the Common Tern have a distinct black trailing edge.  The tail has black edges on the outside.

The real "common tern" in winter is the Forster's Tern, above. It has a black eyepatch, not a cap. Its wings can also have a thin black edge in the back, but the black cuts up as a line into the wing.

The third small tern today was a Black Tern in winter plumage, seen in the last two photos.  In summer, Black Terns really are black.  In winter, the upperparts, the cap, and a little mark that juts down onto the side near the front edge of the wing are all that are dark.  Black Terns shouldn't be here at this time of year, but they are sometimes recorded in Louisiana in late fall.