When I lived in the PNW I got to know my birds really well. The chickadees were some of my favorite to watch, so dexterous and playful at the feeders. He's very right about the (hilarious) aggressiveness of hummingbirds, but I did notice the different species acted very different. Not sure the names but the shiny green ones are far more tolerant of each other (I have a picture of 8 sitting on the same feeder at once). The lighter ones with black/yellow/grey markings are SO mean though! Constantly divebombing and harassing. I did have one other (much more rare) type that was orange, that had the most unique personality. Very sweet and brave, but very much a joker. The way he would taunt and "guard" the feeder seemed more like an invitation to play.