Cockatiels are very popular as pets. The males are more outgoing socially than the females, but are also more aggressive.  Only males have talking ability, and require more attention.  Females are generaly quiet, not as vocal, and don't require as much attention as the males.  There are five different varieties of Cockatiel; Lutino, Pearled, Pied, Cinnamon and Gray.  Cockatiels are native to Australia, and are among the easiest birds to breed.  They make excellent companion birds, as they have exceedingly gentle temperments.