TL;DR: I built a wifi-equipped water gun to shoot the pigeons on my balcony, controlled over the internet by a python script running openCV reading the camera image of my old iPhone.

Our solution: feed the pigeons in a separate place where they congregate in wait. And it works.

I really only wanted to see funny videos of pigeons being squirted but nothing...

The only thing that seemed to work for me was putting a thread across the railing where they used to land. I glued some cheap hooks to the wall either side of the railing and ran a thread over and back.

I’m not sure why it worked. They either can see the thread and get put off, or they don’t see it and freak out when they land on it. I’ve tried both black and white thread and both seem effective. It did snap once probably due to a pigeon being caught out but that’s not a problem.

It doesn’t getin my way either as the thread is loose enough for me to rest my arm on the handrail without it breaking.

My balcony has been crap free for about a year now and it cost like £2 to do.

There's a cat in our neighborhood that shits on our back porches multiple times a day (I have no idea how this is possible, maybe it means the cat will die soon!), and I finally got a huge industrial fan and hooked it up to a motion sensor. Mischief managed.

A loud bang works and you don't have to aim

As always there’s someone on the internet a step beyond. Meet the pussy wetter: https://pussywetter.com/

How does this work with a fixed gun? Perhaps its not a narrow jet as I was assuming. Is a broad cone or mist spray sufficient?

previously:

May 2022, 103 comments - https://news.ycombinator.com/item?id=31377985

Once in the Netherlands I saw the simplest solution to pigeons: they stretched a fishing line an inch or two over the balcony railing, so when pigeons would try to land they’d land on the fishing line and be off balance, flying away to a more stable place.

Seems it worked because the balcony was spotless. I’ve seen similar on European churches.

In my experience, crows seem to be quite an effective natural deterrent.

Maybe a lasting solution would be a convenient, dedicated resting rod laced with a little ceasium-137. You know, so they would be willingly placing their gonads on a gamma emitter. I'd say you likely sterilize most, with only a small chance of creating a supermutant nemesis. You could also add some phosphor to attract mosquitos at night.. and sterilize them, too.

We have a pigeon on our balcony. We picked him when he was only a week old and now he lives with us. Our balcony is isolated from the street, so every morning we open a window there so Theodor (his name; although we're not sure, maybe he is she), so Theodor can go out and fly. In the evening he returns; sometimes he gets stuck somewhere due to rain (they do not fly in the rain) until dark (they do not fly in the dark either) and returns in the morning. We worry a little when this happens.

He is not strictly a pet, we try not to turn him into one and hope he will find a spouse in the spring. In the meantime we'll build him a small house that may serve as a nest if he is so inclined. We've read a few books about them and joined a chat of people who keep pigeons, en masse or just adopt a pigeon who needs it.

We do not do that often but about once a week we catch him and sprinkle with a dust against parasites. Pigeons are very pleasant to touch. The feathers have a silky feeling and they are warm, warmer than people.

There are a lot of excrements, of course. We covered the balcony with cardboard to protect and wear a dedicated pair of slippers. Yet we see these little piles with satisfaction because they mean that Theodor eats well and is healthy. By the way it must be a good fertilizer; old books say it was a source of income for the pigeon keeper.

So maybe you can make friends with pigeons instead of shooting them. The balcony is too small anyway (see "The pattern language"). Give them a bath (they love to bath), make them a feeder. (You can strategically position it so that excrements will mostly fall outside.) They are very lovely creatures.

I started a project this year similar to this with rats. It’s now two axis with tracking and a stereo camera with depth detection. The amount of hours I’ve spent on it is astounding but I’ve learned a lot!

Also, ended up swapping the Pi I started with to a jetson.