Every watch hummingbirds. They are the most ferocious - chase off my cat with no hesitation. But they are afraid of hornets who also like the feeder.
I quit filling my hummer feeder after I moved it up close and saw all the carnage really happening there. Hornets were tackling honeybees and stinging them all the way to
the ground.
The hummingbird v hornet wars were fun, though. My hummers jumped back then BAPPed the hornets for a split second of feeding.