Whenever I got my camera out, the African Greys would come to see and as I filmed up and down the cage, that is where they travelled. They use their beaks to move around. I don't know which one of them made a sound like a smoke alarm that needed to be changed.

Grey parrots are notorious for mimicking noises heard in their environment and using them tirelessly. They are highly intelligent birds, needing extensive behavioral and social enrichment as well as extensive attention in captivity or else they may become distressed.
The grey parrot (Psittacus erithacus), also known as the Congo grey parrot, Congo African grey parrot or African grey parrot, is an Old World parrot in the family Psittacidae. The Timneh parrot (Psittacus timneh) once was identified as a subspecies of the grey parrot, but has since been elevated to a full species.