GeoBeatsNews reports on an experimental London-based project to feed pigeons a special diet that'll make them poop soap. That way, instead of dirtying the city as they fly around, they'll clean it.
The video makes it sound like this is an official government-sponsored project. But as far as I can tell, it's an art project called "Pigeon D'Or"
by Cohen Van Balen. That is, it's probably not really happening. Van Balen offers this description of the project:
With the help of biochemist James Chappell, we have used synthetic biology to design and create a bacteria that can modify the metabolism of pigeons. To achieve this, we have created a new biobrick, or standard biological part, that when added to the genetic information of the bacteria, creates lipase. We have also used a biobrick that lowers the ph. The result is a biological device that produces a kind of window-soap. We have built this device in the bacteria Lactobacillus, which is a bacteria that naturally occurs in the digestive tract. So when feeding this bacteria to a pigeon, it should produce and defecate biological soap.