Three birds that frequent my garden feeders here in Colorado are:
House Finches- which are a type of finch, they will spend a long time sitting on the feeder sorting through seeds and other bits.
Dark eyed juncos- which are a type of sparrow, they go on the ground under the feeder while the other birds feed clearing up the fallen rejected seeds and nuts.
Chickadee- I'm not sure what type a chickadee is... but it seems to fit the behaviour of a flycatcher as it darts back and forth from feeder to branch, but it feeds on nuts and seeds rather than insects from what I can see soooo......?