Melopsittacus undulatus vs budgie

Melopsittacus undulatus and budgie both are nouns.

Word	Noun	Adjective	Verb	Adverb
Melopsittacus undulatus	Yes	No	No	No
budgie	Yes	No	No	No

As nouns, Melopsittacus undulatus and budgie are synonyms defined as:

Melopsittacus undulatus and budgie: small Australian parakeet usually light green with black and yellow markings in the wild but bred in many colors

Other synonyms of Melopsittacus undulatus include budgereegah, budgerigar, budgerygah, grass parakeet, lovebird, shell parakeet.

Melopsittacus undulatus (noun)	budgie (noun)
small Australian parakeet usually light green with black and yellow markings in the wild but bred in many colors	small Australian parakeet usually light green with black and yellow markings in the wild but bred in many colors