An Etymological Dictionary of the German Language/Annotated/Ammer
Ammer, feminine, from the equivalent Middle High German amer, Old High German amero (*amaro), masculine,’ yellow-hammer,’ with the derivative Old High German and Middle High German amerinc, ‘yellow-hammer,’ Middle Latin amarellus, which may have been formed from the German word; English yellow - hammer (Goldammer) is a corrupt form. Whether Old High German *amaro was derived from Old High German amar, ‘summer-spelt,’ is as doubtful as its relation to Amsel.