The sirens are well suited for luring men off a passing boat for a quick meal. Well armed with a seraphic alluring voice, they easily entice men into the water. Their powerful ,mystical voices were known by all sailors ,but that powerful strength means there is a horrible weakness.
Sirens are cooped up like birds in a cage. With all freedom stripped away. Confined to a single island for forever, always wondering when their next meal will come floating to. This is told in Homer's The Odyssey when Circe told odysseus about the