On the way down the coast last Fall, we watched frigate birds at night trying to land on our masthead. We were 10-20 miles off the coast. These birds are awesome fliers, so I think they were just trying to land for the heck of it. This happened mostly at night. Two birds took turns at it with not much success... or so we thought. One of the Windex indicators got rearranged one of those nights. They weren't deterred by banging on the rigging and shouting.

Good luck with your bird predations!