fiddleheadin' \'fid-ul-hed-din\ v - The act of harvesting fiddleheads, the edible juvenile fronds of the ostrich fern (Matteucia struthiopteris), which resemble the heads of violins; "Uncle Richard's goan fiddleheadin' and he wants to borrow your rubbers." Fiddleheads are a local delicacy, and a former dietary staple of the Micmac and Maliseet natives. They grow in boggy areas bordering on rivers and streams, and are delicious. Attempts, some quite ambitious, to cultivate fiddleheads commercially have met with little success. CAUTION: Don't go fiddleheadin' if you don't know what you're doing: mature ostrich ferns (and other wild ferns) are toxic!