bluebird vs thrush

bluebird and thrush both are nouns.

Word	Noun	Adjective	Verb	Adverb
bluebird	Yes	No	No	No
thrush	Yes	No	No	No

As nouns, thrush is a hypernym of bluebird; that is, thrush is a word with a broader meaning than bluebird:

bluebird: blue North American songbird
thrush: songbirds characteristically having brownish upper plumage with a spotted breast

bluebird (noun)	thrush (noun)
blue North American songbird	songbirds characteristically having brownish upper plumage with a spotted breast
fruit-eating mostly brilliant blue songbird of the East Indies	a woman who sings popular songs
	candidiasis of the oral cavity; seen mostly in infants or debilitated adults