Seagulls are bar patrons age 50+ who commonly "fly" from bar to bar abusing already inexpensive food & drink specials, such as happy hour & complentary items. They usually leave without tipping, or tipping very little. They then stumble out of the bar drunk & full-bellied & ready to take advantage of the next place on their list.
1. "Happy hour is about to start, those damn seagulls are about to swoop in!"