bird louse vs louse

bird louse and louse both are nouns.

Word	Noun	Adjective	Verb	Adverb
bird louse	Yes	No	No	No
louse	Yes	No	No	No

As nouns, bird louse and louse are synonyms defined as:

bird louse and louse: wingless insect with mouth parts adapted for biting; mostly parasitic on birds

Other synonyms of bird louse include biting louse.

bird louse (noun)	louse (noun)
wingless insect with mouth parts adapted for biting; mostly parasitic on birds	wingless usually flattened bloodsucking insect parasitic on warm-blooded animals
	any of several small insects especially aphids that feed by sucking the juices from plants
	wingless insect with mouth parts adapted for biting; mostly parasitic on birds
	a person who has a nasty or unethical character undeserving of respect