Forster's Tern

Going through some photos taken at Merritt Island, Florida, I found some of groups of birds quite a bit in the distance. In cropping them I encountered a species I'd not seen before, the Forster's tern. 

Forster's tern range from Wikipedia. Blue is non-breeding, purple is year-round, yellow is migration and orange is breeding. I was in Florida in January, so I saw non-breeding. 

It has pale gray upperparts, white underparts, red legs, and in winter, the forehead is white with a black eye mask. At other times of the year the bill is red and tipped with black and it has a black cap. 

Two Forster's terns on the far right (the front one has beak pointing down, the back one has the readily identifiable black eye mask). I'm not sure what the other birds are. 

A more cropped but blurrier photo.