How long was the feeder down? Some of the hummingbirds may have thought their nectar source was gone and moved on. They are like that.
I know my hummingbirds are very demanding and it's a daily chore to make sure the feeders are full. They do have favorite feeders that seem to empty faster than the others. I haven't figured out why, the favorite is green and of course the smallest feeder out there - maybe the nectar is always fresh?
Adding some of your pretty artwork is a good idea!