sky·lark (skī'lärk') n. An Old World lark (Alauda arvensis) having brownish plumage and noted for its singing while in flight. intr.v.
sky·larked, sky·lark·ing, sky·larks To play actively and boisterously; frolic.
the common European lark, 1686, from sky + lark. The verb meaning "to frolic or play" is recorded from 1809, originally nautical, in ref. to "wanton play about the rigging, and tops."