Squawk

Squawk was a bird made of living metal from Pheros. He served Baltazar as a spy. His father was Caw, whom Squawk mourned. Squawk was disguised as a small brooch given to Martha Jones by Caw. Squawk eventually revealed himself to be alive and flew away. When the Doctor's TARDIS was hijacked by the space pirate Baltazar, the Tenth Doctor waited until Squawk had grown big enough to ride upon and travelled to the Infinite to rescue Martha. After the Doctor defeated Baltazar, Squawk took him to the prison planet Volag-Noc, where he belonged. (TV: The Infinite Quest)