The trillions of bacteria living in our guts play a crucial role in our ability to digest food and fight off disease. All other animals also have communities of bacteria living inside them, that scientists call microbiomes, and learning about them can help scientists put together a more complete picture of how those animals interact with the world. In a new study in the journal Molecular Ecology, researchers used tiny radio trackers to follow the movements of birds that migrated between The Bahamas and Michigan, and they found that the same individual birds' gut bacteria were different in the two locations. And to figure that out, the scientists had to get up close and personal with a lot of bird poop.
source https://phys.org/news/2021-09-bird-poop-reveals-birds-migrate.html