Litter Disposal for Pigeons




About: I'm an electrical engineer, musician, and giant nerd. My school experience was mostly digital signal processing. My real-life work experience is with audio electronics: microphones, mixing consoles, guitar...

Note: This is more of a proposal or idea than a set of instructions for how to build something. I thought "enable collaboration" meant "collaborative design of something that doesn't exist yet". But it seems Instructables are only for things that already exist.

Cities have a number of problems due to the huge numbers of people that frequent them. One is that irresponsible slobs (including lazy garbage collectors) leave trash all over the streets. Another problem is the excessive pigeon crap left everywhere because the excessive edible trash is conducive to them breeding all year round. How do we improve both problems at once? Train pigeons to pick up litter!

This was inspired by a great idea I saw on the halfbakery; I didn't come up with it. That's generally a speculative, sort of half-serious site, but I think this is one of the ideas that might actually work. I wonder if such a device could be designed and built collaboratively...

So my first mental image was big bins in places that are accessible to birds but not frequented by humans. They'll accept certain types of garbage, and dispense tasty pigeon treats in exchange. Teach a few pigeons to drop garbage in the bins and get a reward, and the rest should learn by example.

(I thought it might improve the poop situation by moving the pigeons to an area away from people while they eat, but I don't know if that would really work. Where do pigeons poop?)

One problem with this idea is that you would need to encourage them to pick up things that are actually trash, and not things like stones or hats. (How much can a flying pigeon lift?) The first thing I imagined is some kind of scanner like they have for bottles and can recyclers, but that's quite complicated and very error prone. How would you identify squashed, torn paper cups?

Although a lot of people hate them, pigeons are pretty smart. They can distinguish between Picassos and Monets, for instance, and were even considered for guiding missiles in World War II. Identifying pieces of trash should be easy; they already do while scavenging anyway.

So I wonder if there's some more elegant way...

Step 1: Cigarette Butts!

Cigarette butts are a universal problem ( says that they are the most littered item in the world; in the billions per day, and they're carcinogenic and toxic to fish as well). They are uniform in shape and color, making it easy for a machine to recognize them pretty robustly. They are small and light, so no problem at all for birds to pick up. So now I'm imagining, for the first proof-of-concept implementation, a device that is meant exclusively for cigarette butts. This would greatly simplify the problem while still doing a lot of good (if it works).

Try to imagine your own version of how such a device would work before opening the next page, so your ideas aren't tainted by mine. :-) Leave your alternative good ideas in the comments.

Step 2: Passive Mechanical Device?

So then I imagined a device with a little hole on top for the birds to insert cigarette butts. It would suck them in with wheels or something, make sure they are actually butts (measuring the length and color?), and then dispense a piece of food.

The piece of food would have to be very nearby the deposit hole or other birds would learn to stand nearby and steal it when it pops out.

But even this is rather complex. Does it really need to be? False positives could just be sorted out after the fact just by scanning through the collection visually when it is periodically emptied. Hmmm...

So what about a purely mechanical, passive device? The bird has to physically push the cigarette butt with a little force, which pushes some type of mechanical linkage/lever, and then a similarly-sized pellet of food is propelled out the same hole, right near the bird's mouth. The food can be reloaded into the dispenser by gravity, with a hopper on top, and the butts can fall into a container below.

We'd need to worry about the thing jamming, I bet, and squashed butts might not have enough structural integrity to be "pushed" into a hole against a little resistance. It would probably need to be low-maintenance, but maybe not. Maybe getting jammed once a week wouldn't be that bad, if it's emptied once per day by a worker.

The container could not be a bag, and could not have gaps anywhere, or the birds would just take them out and cycle them through again.

But a rough sketch is not the same as actual instructions for building a real device. Please leave comments to help design this. What other practical difficulties would it have? How would the mechanics work? I'm not a mechanical engineer; I can't see this stuff intuitively.

Step 3: Training

I have no idea how you would go about training pigeons, but we know that they learn by example, so you should only need to train a few and the rest will follow. This is kind of how you train cats to use the toilet:

1. Dump some butts on the ground (or maybe "dummy butts" that have the same properties but are not harmful to the environment if they don't get picked up)
2. Feed some pigeons in the area around the device to gather them in a group.
3. Then feed them from around the device itself
4. Then put the fake butts in the machine and allow them to retrieve the food that comes out
5. Then put some fake butts on the machine itself?

Ok. I've explained what I am imagining for this device. Now everyone else fill in the gaps!



    • Beauty Tips Contest

      Beauty Tips Contest
    • Frozen Treats Challenge

      Frozen Treats Challenge
    • Classroom Science Contest

      Classroom Science Contest

    23 Discussions


    4 weeks ago

    This is already being done with crows- see link to an amusement park in France that has a murder of crows that pick up cigarette butts -
    As for identifying and picking up other types of trash, see this TED talk that proposes a device that will train crows to pick up trash after stadium and concert events -

    1 reply

    3 years ago



    8 years ago on Introduction

    So what if this produces a shortage of cigarette butts in the street. Would the pidgens resort to stealing unused ones or ones occupying peoples mouths? This solution may also increase general health!

    1 reply

    4 years ago on Introduction

    i keep pigeons as pets, they are not the feral type but the fancy feathered ones, they are cute but i assure this bird is such a nut it simply wont learn a thing.


    9 years ago on Step 2

     Ive heard of something similar to measure the learning ability of crows--- it involved pennies and peanuts, could be crossed over to pigeons though, awesome idea! put those fat flying rats to work! lol


    9 years ago on Introduction

    Rather than training birds to do a smoker's job, train the smokers to use the bins provided or carry their own ash tin to empty later on, that solves that problem... ;) Littering, again, requires training of humans to sort that problem out, if everyone did as they were told to and put their litter in the bin, then we'd all be happy... :) As for pigeon poo, well, it's a fact of life, can't get away from it, it happens... :(

    2 replies

    Reply 9 years ago on Introduction

    Personally? Threaten them with tier lives, but we know that'll never happen, but it probably would work... :)


    10 years ago on Step 2

    How about a wheel or something like a revolving door? When the butt is inserted by the bird with a little push of the beak, the get a reward simply by mechanical movement. There still is the butt detection problem... Well, I also imagine birds sitting in trees and watching the smokers finish their cigarettes, just to shoot down and catch them before reaching ground, when disposed! Nice Idea!

    1 reply

    Reply 10 years ago on Step 2

    How about a wheel or something like a revolving door?
    When the butt is inserted by the bird with a little push of the beak, the get a reward simply by mechanical movement.

    Yes, that's what I was thinking. But what mechanism specifically? Need someone who knows about vending machine mechanisms or something.

    There still is the butt detection problem...

    Heh heh heh. :) But yeah, the mechanism has to somehow only work for cigarette butts, and not sticks or whatever.

    Well, I also imagine birds sitting in trees and watching the smokers finish their cigarettes, just to shoot down and catch them before reaching ground, when disposed!

    Yes, I imagine that too. :) People will probably throw them on the ground more when birds are around, knowing that they will pick them up.


    11 years ago on Step 3

    This is a really good idea, but who's going to build the machine and do the training? It's a real long shot but seems to be an effective way to deal with the problem.

    3 replies

    Reply 11 years ago on Step 3

    Yeah. I could help build it but couldn't do it all myself. I thought "collaboration" meant "collaborative design", but apparently it means "collaborative writing about something that's already done".


    Reply 11 years ago on Step 3

    A good idea would be to train select young pigeons, release them in a common area, and let the rest learn from them. Monkey see, monkey do type thing.


    11 years ago on Introduction

    how much energy is being put in compared to the energy coming out? EXAMPLE; the time, money, and energy it takes to make a bird pellet v.s. the time, money, and energy it save to have the pigeons pick up one butt. I think it needs a little work, but keep up the good ideas. I just think you need to think larger.

    1 reply

    Reply 11 years ago on Introduction

    Well, 5 lb of pigeon food costs $4. So a device of the size I'm imagining wouldn't cost more than $10 to fill with specially-made pellets. Probably less. Now how much would it cost to pay a human to pick up the same amount of cigarette butts?