My idea for one way film inside my kitchen window which has a window feeder attached to the outside is helping. They still seem to maybe see me sometimes, but they aren't flying off the moment I move. I can't see them as clearly because the film makes things darker, so sometimes it seems like I'm seeing a silhouette. Even so, that's a lot better than them flying off! I don't get the idea that they are afraid of their reflection. It seems that they don't see their reflection or don't see it as a rival bird.
At the moment it seems that there's 2 birds hitting the window feeder (not at the same time). One's relatively big... and stupid! It doesn't perch while feeding, it keeps flying, backs off 6 inches, comes back and feeds with wings beating, hovering. The other bird feeds at the opposite synthetic flower portal and perches while feeding. It's much smaller. It's the rare HB that doesn't perch while feeding at my feeders. I have 5 now, including the window feeder. I wonder what winter's going to be like. Coldest nights are almost never below freezing.