birdseed vs bird food

birdseed and bird food both are nouns.

Word	Noun	Adjective	Verb	Adverb
birdseed	Yes	No	No	No
bird food	Yes	No	No	No

As nouns, birdseed and bird food are synonyms defined as:

Other synonyms of birdseed include bird feed.

birdseed (noun)	bird food (noun)
food given to birds; usually mixed seeds	food given to birds; usually mixed seeds