Scirroco is the Silverwing leader of the group of the banded bats, which included Penelope. He renamed the bats and tricked them with optical illusions, which are actually the result of his echoprojection.
The banded bats resided in a cabin, which was attacked by Goth and Throbb. While Penelope and most of the other bats escape, Scirocco's fate is unknown. It is implied that he was eaten by Goth or Throbb.