You may see birds near a feeder but that doesn't mean they're nesting there. Trees and shrubs near feeders are merely staging areas - intermediate perches to see if a feeder or birdbath is safe, or the food's promising.
A nesting bird doesn't want to be scrutinized for even a second. She (usually it's a female) is terribly vulnerable and the nestlings are helpless.(That's also why most female birds aren't brightly colored)
A reader's remedy for birds smashing into windows. It consists of strips of cloth hung about a foot from the glass and weighted with small clay pots.