How you can watch birds close up in their natural environment right from ANY WINDOW with the Spy Birdhouse! Just attach the birdhouse using the all weather suction cups to watch birds nests, lay eggs, hatch baby bird, and feed! The included one-way mirror sticker attaches to the Plexiglas window cover and allows to see the birds without them even knowing you there. Instals in few seconds with no tools and is educational and fun for all family. This My Spy Birdhouse is perfect for kids. Allows for them to get a close glimpse at birds and how they live. The clear, acrylic window with 2-way mirror film lets you see birds inside, but they can't see you.