Bird Tapping on Windows

I've had a strange experience that has happened 3 days in a row now, and I just want to get some opinions :)

There has been a bird (a goldfinch, to be exact) that has tapped on both my living room and one of my bedroom windows, for the last 3 days in a row. I do have a birdfeeder in the back yard...but the windows it taps on are both in the front of the house - I have not once seen it in the back! The living room window has somewhat sheer curtains in it that are always closed, so it's not like the bird can see straight through the window to another window (thinking it can fly straight through...) If you looked in the bedroom window from the outside, you only see the opposite wall- no other window - no mirrors, etc....and for the bird to tap on either of the windows, it has to literally cling to the brick surrounding the window, and lean over to tap the window with its beak! I have gone to the living room window while it was tapping - the window was open at the time - and it just looks at me & keeps tapping even while I talk to it!
The only association I make with this is that my mother always loved birds, and the goldfinch was her favorite bird. She has been deceased for several years now, but I can't help but wonder if it is her spirit somehow coming to "visit" me?? But why now, after so many years of nothing before? I haven't been thinking of her, or missing her, any more lately than I ever did before.....
Or is there some other possible significance to this?
Any ideas or thoughts? I just find it a bit odd.... :)