More to explore:
Gardener's Supply Window Nest Box Birdhouse | Buy this glass backed bird house and observe the whole nesting process right outside your window with this handcrafted nest box. It has suction cups that attach easily to any window, and a 1-1/2" opening that suits most song birds
Backless bird house with suction cups for the window= you get to see the baby birds hatch! Or a bird feeder at a kitchen window while washing dishes.
Window Nest Box Birdhouse. What a cool idea!
Backless bird house with suction cups for the window. Bird's nest watching. Window nesting box