Guano is the name of poop for seabirds and bats.
The penguin poop has a reddish tint, probably due to the krill that the penguins ate.
Watching the penguins poop was probably the cutest thing about the whole trip. They would stand up, pop their bottom out, squirt it all out, then shake their tail feathers in celebration of their great feat.
They didn’t care where their guano went, as a result many penguins had streaks on their back or pink on their usually white chest. The clean ones had been on a swim recently.