Most parrots can copy sounds, but grey parrots are different. Scientists have shown that they can actually understand what some words mean. A famous African grey called Alex learned over 100 words. He could name colours, count to six, and even say 'I'm sorry' when he had done something wrong.
In the wild, grey parrots live in big flocks - sometimes hundreds together. They sleep in tall forest trees and fly out in noisy crowds at sunrise to find fruit and nuts. They love palm nuts most of all. Their strong beaks can crack open shells that humans need a tool to break.
Grey parrots are very social. They greet each other, share food and look after each other's young. Pairs of grey parrots stay together for many years. They are one of the few birds that hold things in their feet, the way a person uses a hand - they will pick up a nut, turn it over and look at it before deciding to eat it.
Because they are so clever, grey parrots have become very popular as pets in many countries. The wild grey parrots in Nigeria are now protected so they can stay safe in the forest where they belong. A grey parrot in the wild can live up to 60 years - so a chick born this year could live to be older than most of the teachers in your school.