bird fancier vs enthusiast

bird fancier and enthusiast both are nouns.

Word	Noun	Adjective	Verb	Adverb
bird fancier	Yes	No	No	No
enthusiast	Yes	No	No	No

As nouns, enthusiast is a hypernym of bird fancier; that is, enthusiast is a word with a broader meaning than bird fancier:

Other hypernyms of bird fancier include fancier.

bird fancier (noun)	enthusiast (noun)
a person with a strong interest in birds	an ardent and enthusiastic supporter of some person or activity
	a person having a strong liking for something