 For example, "Alexandrine parrot" and "Alexandrine parakeet" are two common names for the same species, "Psittacula eupatria", which is one of the largest species normally referred to as a parakeet.Many different species of parakeets are bred and sold commercially as pets, the budgerigar being the third most popular pet in the world, after cats and dogs.Budgerigars are great companions for any age and can be easily trained.