Also, when seeking a mate some male cockatoos are much more aggressive than others. In captivity, the males who show this tendency are often physically very large birds, who also project a great deal of intelligence and often present quite a challenge for their owners around the age of 3-5 years. It occurs to me that these qualities are what best suits that leadership role in the wild. In the wild, they would merely use body posturing and vocalizations to claim their territory, nesting site, or mate, with perhaps the occasional beak battle. However, the freedom to take flight along with the vastness of their natural habitat, prevents these squabbles from becoming major altercations.
African greys are extremely social birds in their natural habitats.
They have constant flock interaction. A recent informal survey had some interesting results regarding long-time bonding patterns with African grey parrots. The birds in the survey were all three years or older, domestically bred, DNA sexed and lived in households of two or more people. A common complaint about African greys is that they don't always choose to bond with the person they were originally intended for. For instance, a grey might be raised by the wife in a household, only to decide it wanted to be close to the husband a couple of years later.