Harpy

Harpies are flying enemies added in the 1.0.4 patch. They spawn at high altitudes, typically between the height of Floating Island and the top of the map. There are blue and red winged varieties and they fire projectiles in volleys of three.

Harpies can spawn in both day and night, it is possible that their spawn rate is increased during dawn and dusk.

Their spawn rate occurs more often the closer you are to the top of the map, as at the minimum depth Harpy is a rare spawn where other monsters can spawn in its place still, where at the top of the map there is nothing but Harpies.

The Harpy monster uses the obvious Flying AI but with a twist. Instead of just ramming into the target like a Hornet or Demon Eye would, the Harpy attempts to ram the target and also shoots volleys of 3 feather-like projectiles. These feathers cannot be deflected with a weapon and do 30 damage when unarmored (16 damage with full Molten Armor). When it rams into the player the damage is slightly less, dealing 25 unarmored (11 damage with full Molten Armor). The feathers are destroyed on contact with any block.

There can be up to 6 Harpies attacking you at once. They tend to eventually group together in 1 single bunch if left alive, probably a bug with its AI. This makes it seem like it unleashes an endless fury of feathers at you.

When killed, the Harpy's body is destroyed leaving nothing but its wings on the ground.

The Harpy seems to not drop anything other than 1-5 Silver Coins and a 0-5 Copper Coins, 4 and 5 silver being most rare but have witnessed a single Harpy dropping 8 silver and 3 copper coins.