I just had to ask, having watched a gull flying around for five minutes trying to find someplace to land and devour the tasty morsel he'd found without having it stolen from him by the gang of muggers flapping after him. Why is it an evolutionary advantage -- which it must be, or it wouldn't have developed -- for a dozen gulls to fly around for five minutes, thereby expended 60 gull-minutes worth of calories, when in the end only one gets to eat?