This card's effect that Special Summons a "Harpie" monster from your Deck starts a Chain. (It does not target.)[1]
This effect can be activated optionally at the end of the Damage Step if a "Harpie Lady" or "Harpie Lady Sisters" in your Monster Zone is destroyed by battle.[1]
This card's effect that Special Summons a "Harpie" monster from your Graveyard starts a Chain. (It targets 1 "Harpie" monster in your Graveyard.)[1]
This effect will activate when this card is destroyed by your opponent's card effect or by your own "Harpie" card's effect. (It will also activate during the Damage Step.)[1]
Q&A Rulings
Q: "Skill Drain" is face-up in my opponent's Spell & Trap Zone, and its effect that negates the effects of face-up monsters on the field is applying. In this situation, if a "Harpie Queen" on my field is destroyed by battle, can I activate the effect of "Alluring Mirror Split"?