Bird I.D. Possibly a Tern

Can anyone tell me what type of bird this is? I think it is some sort of Tern. It was photograhed in Louisiana. It is much smaller than the Gulls it was flying around.

It looks the the bill has a yellow tip so I would say a Sandwich Tern

It does have a yellow tip.

It's hard to see if the beak is black with a yellow tip or not, which would positively ID it as a sandwich tern as Mia says, but it's definitely a tern. A sandwich tern isn't much smaller that the smaller gulls, such as a laughing gull, which is the only gull present now here on the south gulf coast. Do you have any other pictures of it?

I agree with Mia, Buck. BNA says,

Only crested tern with a black bill; at close range, yellow tip of bill separates it from all other North American terns. Legs black. Rather slim tern with long narrow wings.

All of which seems to fit your bird.