Mauro is the quaternary antagonist of "Rio". He is the king of the marmosets. One can tell which is him by the brown fur, the extra bunch of hair, and the paper clip in it, while the rest have gray hair and not that much. They steal valuables from tourists, with Mauro distracting them. They are extorted by the cockatoo Nigel into helping him find the two blue macaw heroes Blu and Jewel. When Mauro asks what is in it for them, Nigel carries him high in the air and drops him, tricking him into asking to be saved in return. Mauro and his henchmen scurry along and then find Blu and Jewel at a samba party with other birds. Eventually, Blu, Jewel, and their bird friends fight with them, until the birds win, and what's proven is when Roseate Spoonbill Kipo gives the macaws a lift onto a trolley. Nigel finds the mess and berates Mauro and throws a scared green bird at him.
Mauro is never seen again until the between-credits scene when Nigel is shown to have lost almost all of his feathers, and Mauro humiliates him by taking pictures of him and laughing at him. Absolutely, not even then are his followers seen again. This photo continues the credits.