genus-Milvus vs bird genus

genus-Milvus and bird genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus-Milvus	Yes	No	No	No
bird genus	Yes	No	No	No

As nouns, bird genus is a hypernym of genus-Milvus; that is, bird genus is a word with a broader meaning than genus-Milvus:

genus-Milvus (noun)	bird genus (noun)
a genus including the common European kits	a genus of birds