tyrant bird vs tyrant flycatcher

tyrant bird and tyrant flycatcher both are nouns.

Word	Noun	Adjective	Verb	Adverb
tyrant bird	Yes	No	No	No
tyrant flycatcher	Yes	No	No	No

As nouns, tyrant bird and tyrant flycatcher are synonyms defined as:

tyrant bird and tyrant flycatcher: large American birds that characteristically catch insects on the wing

Other synonyms of tyrant bird include flycatcher, New World flycatcher.

tyrant bird (noun)	tyrant flycatcher (noun)
large American birds that characteristically catch insects on the wing	large American birds that characteristically catch insects on the wing