When I 1st saw them, they were too far away to ID for sure. But, luckily I only had to wait a little while for them to fly when something spooked the gulls. The black underwings, wingstripe, and black and white tail pattern were literally visible from about 1/2 mile away when they flew around the area. They came right back to this same spot though, which started quite an adventure for me trying to get some photos.