Just a suggestion to check with the office or your lease to be sure it’s ok to feed birds from your balcony. There may be rules against it because of the mess potential. My daughter’s condo assn. won’t allow it.

You might plant flowers that they are attracted to in the pots on your balcony, in addition to hanging feeders. Are you able to add window box frames to your deck railing? They might not be approved by your HOA, so check first!