tree sparrow vs true sparrow

tree sparrow and true sparrow both are nouns.

Word	Noun	Adjective	Verb	Adverb
tree sparrow	Yes	No	No	No
true sparrow	Yes	No	No	No

As nouns, true sparrow is a hypernym of tree sparrow; that is, true sparrow is a word with a broader meaning than tree sparrow:

tree sparrow: Eurasian sparrow smaller than the house sparrow
true sparrow: any of several small dull-colored singing birds feeding on seeds or insects

Other hypernyms of tree sparrow include sparrow.

tree sparrow (noun)	true sparrow (noun)
Eurasian sparrow smaller than the house sparrow	any of several small dull-colored singing birds feeding on seeds or insects
finch common in winter in the northern U.S.