Same here. I have a hibiscus next to the window and a few times I saw a shadow move across my peripheral vision and then it was gone. A couple of days ago I finally saw what it was. No, not my imagination, although it is formidable and casts its own shadow. It was a hummingbird in the deep dark shadow of my looming imagination and the fact that the low-angled sun was blocked by the fence. No longer having the feeder up I don't get to see many hummers. It sounds like you haven't seen many this year either.
