Why is it that some say that parakeets are the same as budgies and other say they are different birds. Which is correct?

Parakeets and budgies refer to the same species, Melopsittacus undulatus, but the term "parakeet" is a broader classification that encompasses various species of small to medium-sized parrots with long tail feathers. In casual contexts, especially in the U.S. and Canada, "budgie" specifically refers to the domesticated version of this bird. Therefore, while all budgies are parakeets, not all parakeets are budgies. Thus, those who say they are the same are correct in the context of the species, while those who differentiate may refer to the broader classification of parakeets.