Use tape to adhere them to your window. My windows have screens on the side portions inside, so I had to tape my bats up OUTSIDE. I was worried about them staying put in the harsh winds this time of year, so I used packing tape.
And you're done! I love that it looks a little like specimen art. (Which was totally trendy last year, and not so much now. Huh.)
By day, you can see different "species" (classified by scrapbook paper pattern) and by night...
If you had a silhouette, this would be even easier. (I mean, I ASSUME it would...)
Of note, I bent the bats wings up a little at different angles and amounts for variety. The packing tape did its job very well and we didn't lose a single bat - even though there were many days when I almost blew away myself. Actually, on those days it was kind of fun to watch the bats since they looked like they were flapping against our window...
And they came off the window smoothly - no packing tape residue. Phew!
I had extra, so I decorated inside our front door too.
I imagined the window was the moon and the bats were circling...
Easy? Why yes! Yes it is! Aren't those the best holiday crafts?