Gukko were a species of large bird-like Rahi. Gukko birds were extremely swift, and generally peaceful, though they would fight if threatened. The Le-Matoran on Mata Nui often tamed Gukko for their Gukko Force. Gukko were also present on Metru Nui, where they lived in the tangled cables of Le-Metru.
The Gukko bird had three close cousins:
- The word Gukko may actually have been an insult in the bird's language, as told by Rahaga Kualus.
- The word "Gukko" was originally Kahu and Kewa. However, due to a lawsuit by Māori activists, they were changed to Gukko. Strangely enough, the actual Kewa and Kahu models were different from the present Gukko's. This was rectified when the Kahu and Kewa were reintroduced to the canon as close relatives of the Gukko.