A bird, said to be very salacious, hence a prostitute or courtesan.
“Here's Agamemnon, an honest fellow enough, and one that loves
The Ilaid of Homer is based on the story that Agamemnon, being obliged to give up his mistress, took the mistress of Achilles to supply her place. This brought about a quarrel between Agamemnon and Achilles, and Achilles refused to have anything more to do with the siege of Troy.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894