The African Grey
The African Grey parrot has a lifespan of more than 40 years. The world's oldest parrot (an African Grey) was 89 years old.
It is one of the most intelligent birds on the planet, and one of the most talented talking/mimicking birds as well. A lot of them not only has a very vast vocabulary, but also seem to understand the meaning of some words and phrases.
Only expert bird owners should keep them as a pet, just like for the Cockatoo; they are extremely demanding, complex, and sensitive. They're just like a child, and are as intelligent as one!