(The). Shakespeare refers to two peculiarities of this bird; (1) to allure persons from its nest, it flies away and cries loudest when farthest from its nest; and (2) the young birds run from their shells with part thereof still sticking to their head.
“Far from her nest the lapwing cries away.”
Comedy of Errors, iv. 2.
“This lapwing runs away with the shell on his head.” —Hamlet, v. 2.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894