What keeps birds from seeing you when you use a window view bird house?

Question

I would like to buy a bird house that you attach to your window with suction cups, & theres a piece of clear acrylic on the back of it so you can watch them make a nest, etc., from inside your home. But my question is (as stupid as it may be) what keeps the birds from seeing YOU in the house watching them? Seems to me they would fly out of their little house when they see you walk up to the window, thus defeating the purpose. Does anyone have one of these & could give me some insight before I buy one?

Answer 1

We have two, one in the kitchen window and the other in my 3 yr olds window.  The birds slowly get used to seeing you and then stop being scared and stay to feed.

Go for it, they are wonderful.