I'm having one right now! One little Rufous has driven off all my other birds. I have to go stand by the feeder so they can come in and load up w/o this bird attacking them. I may have to get a badminton racquet.
The black-chinned one is trying to do that here, too, but so far the anna's far outweigh the pair in sheer numbers! My male is sooo sneaky - I spent quite a bit of time out yesterday with just the one "spot" open (got some nice shots - thank you for the tips!) had to go inside for less than a minute, came back out and there he was guzzling down the nectar, I get to the right angle to catch his blue throat - and he's outa' there, never to return LOL, at least for the rest of my available time but I will prevail!!
The best time is dusk when they have to feed. Set the camera speed=100-250, ISO=100-400, Aperture to ~f/8 Make sure your flash sync speed is set to 1/320FP. Set the strobe to manual and the setting to between 1/8 power to 1/64 power. That range is roughly 1/6000 seconds to 1/30,000 seconds. The nice thing is the strobe, if you use a Nikon extension cable, will fire at high speed. Try to keep the strobe off the camera or you will get strong reflected light from the iridescent pigments in the feathers.
Thanks, Cecily! If there are hummers in the area, they will find it. You can hang a couple of red ribbons from it that may help. Currently I have one bird in my backyard who has driven all the others away. He's guarding the rear two feeders, but can't guard the front feeder. Time to go rent a giant hummingbird costume!