Pigeon Problem

I've got the same problem with the ledge of my 23rd-floor balcony and have taken a multi-pronged approach. I work from home and am looking out the window to the balcony most of the day, so I've had some time to see what works.

First, I cleaned all the poop off the ledge. This was helpful because I'm now more inspired to keep it clean and will agitate any pigeons that do land, instead of sitting and looking at them while reading metafilter. Also, it did seem to help slightly; the pigeons are slightly less like to hang out and poop on the clean ledge than when I let it go.

Then, I printed out an owl and stuck it on some cardboard. I moved this around in the window every day. This had a slightly positive effect, but really didn't seem to do much.

My wife's cousins had a plastic owl in their basement that they sent up our way. This worked better than the printout, although we still got some visitors. I'm pretty sure that at some point a pigeon will land directly on the owl; I hope I have my camera ready then.

Sometimes I hang the owl upside down from a hook mounted in the balcony ceiling. This has the advantage of letting the owl sway in the wind and seems to deter the occasional pigeon.

Even with the owl and the clean ledge I will get a few of the sky-rats. So last week I placed a poland springs bottle full of water by the door to the balcony. Whenever a bird lands I go after it with the spray. I got a few birds at first, but now they fly away as soon as I set into motion from within the apartment, so they are catching on.

I still have to clean the ledge once or twice a week, but it's now just one or two poopstains instead of 10 or 20. The plastic owl helped a little, but I think keeping the ledge poop-free and spraying at pigeons that do land are the most effective approaches.