The Baby Macaws are Blu and Jewel's offspring. They make a short appearance in the end of the film singing "Real in Rio" with their parents. It is apparent that their only purpose is to further repopulate the Blue Macaw/Spix Macaw population in the film. While they are heard singing at the end of the film during "Real in Rio" for half a line, their voice casts aren't listed in the end credits.
It is apparent that their only representation is to convey that Blu and Jewel have successfully started a new life together as a family in a whole new settlement and that they have saved their species from extinction.
It has been revealed by Carlos Saldanha that the three baby macaws seen during the end of Rio was actually an early depiction of Blu and Jewel's children featured in this second film. They have a boy named Tiago (the youngest brother) and 2 girls named Carla (the eldest sister) and Bia (younger sister).
These three baby macaws are not featured in the 2nd film as it was first speculated.