A couple days ago, I was reading this thread with great interest because we have a pigeon problem over the back door of our store. For the past few months the birds have been sitting ontop of a light fixture, old alarm box, & our air conditioner outside the back door. No nest but lots of bird doo all over the wall, door, & approach to back door. We clean it & with in hours there's more. About 5 years ago, my father (god rest his soul) put a bunch of finishing nails in some pieces of wood to create spikes and set them where the birds sit. It has kept them away until this spring. Now the new group of dam birds sit ontop of the nails!
After reading the posts in this thread, I go to work & there is a guy power washing the bakery a few doors down. I flip the guy $10 & have him power wash our bird doo. Not wanting to waste my $10, I beat feat to Target to either buy the "Bird Proof" @ ab $17 or the spikes for ab $40. I arrive at Target and find these products not available at stores, only on line.
On the way back to my store I stopped at the local Grainger to pick up the drill kit we ordered & asked if they carry these products. Answer: yes - not in stock, must order in - price = Jug of sticky stuff @$119 & spikes @ $400!

Looks like I need to buy on line. Then power wash. Bird doo is already back!