> real hawks they hired to scare the gulls apparently got turfed out by them
Lots of raptors, especially falcons, are essentially specialised sprint predators and won't pick a fight with another bird any more than a cheetah would try to fight a hyena.
Interestingly, pigeons fly fast and in a straight race can outfly many falcons. The falcons rely on a very fast stoop from above, slamming talons-first into the target bird hard enough to break its neck or even decapitate it.
Lots of raptors, especially falcons, are essentially specialised sprint predators and won't pick a fight with another bird any more than a cheetah would try to fight a hyena.