I learned from the book "How to Hide an Empire" that an initial motivation for US imperialism in the Caribbean was to harvest bird droppings for fertilizer, even to the point of conflicts with Britain and Venezuela: <a href="https://www.vox.com/2014/7/31/5951731/bird-shit-imperialism" rel="nofollow">https://www.vox.com/2014/7/31/5951731/bird-shit-imperialism</a><p>There was a 1856 law that encouraged US citizens to claim land for the country if there was bird poo on it:
<a href="https://en.wikipedia.org/wiki/Guano_Islands_Act" rel="nofollow">https://en.wikipedia.org/wiki/Guano_Islands_Act</a><p>This law is how the US originally got possession of Midway, which became very well-known during WWII (I always wondered how the US got it originally):
<a href="https://en.wikipedia.org/wiki/Midway_Atoll" rel="nofollow">https://en.wikipedia.org/wiki/Midway_Atoll</a>
Lots of pigeon towers in the countryside in France, nice pictures here:<p><a href="http://www.alaingillodes.fr/patrimoine/pigeonnier/tarn.htm" rel="nofollow">http://www.alaingillodes.fr/patrimoine/pigeonnier/tarn.htm</a>
> First, unlike chickens or ducks, wild pigeons are extremely low-maintenance<p>Until there are 5000 of them on the crop you've just sown. I've shot crop protection before. A large flock can destroy a crop in a few hours.<p>This whole thing relies on your crop not being the crop they want to eat.
On our small farm, we use ducks for fertilizing our fruit trees. We put a temporary fence for them around a tree.The ducks are out during the day, at night inside the fence. After a week or so we move the fence to another tree.
In 1957 Fleming wrote his sixth James Bond book, Doctor No -- in which the eponymous villain runs a guano mine in the Caribbean.<p>Even some decades after the Haber–Bosch process was invented, stripping massive islands of these resources was still lucrative.
>Provide water and shelter, and they will come<p>I find this hard to believe. There has to be a lot more to attracting the pigeons?<p>Reminds me of a recent trend, at least in Sweden - Bee hotels. Small bird house like things that are said to attract bees. Everyone started selling them for a while. I bought a few of them to friends. But I don't think they got used.<p>Putting up a structure and expecting it to just work seems a bit optimistic. Is there more to the secret sauce?
> It’s no surprise that the region that gave birth to agriculture has also refined innovative sustainable agriculture methods for thousands of years. Pigeon towers were one such innovation—and they helped Persian farmers cultivate all kinds of crops on previously arid, thin-soil land.<p>Didn't ancient Persia originally have much more fertile soil, but unsustainable practices (like the introduction of goats) destroy the soil quality? I guess both can be true, initial poor practices necessitated the introduction of more sustainable techniques.
Something that stands out to me is that these structures look very time consuming to produce by hand, but the designs are well suited to 3D printing from concrete or similar materials. Though I don’t know if 3D printed concrete can accomplish “bridging” as is done with plastic 3D printing.
It's nice but it doesn't scale to the level of fertilizer use required today.<p>Most people are innumerate (including people who should know better and could run the numbers) so they don't have a grasp of scale.