The goldfinches are funny. They are so territorial for being so tiny. I have 2 finch feeders outside my kitchen window, and despite the combined 12 perches, they will often run one another off and try to have a whole feeder to themselves. They weren't quite so bad in the summer and all the perches stayed full much of the time, although there was still a lot of jockeying for position. Tiny? Did I say tiny? Well, they started out that way. Now there are a couple of them that seem like they could roll right off their little perches.
Hummingbirds are very territorial..I have seen 10 birds trying to get at one feeder..when there are other feeders just alike nearby. Others(male) stake out one feeder as "theirs" and attack any hummingbird that attempts to feed from it.