Sparrow

A sparrow was an bird native to Earth. They became extinct by the mid-22nd century due to the Ozone Purge of 2106. (PROSE: Lucifer Rising)

The Seventh Doctor, while defending his refusal to take down Sherilyn Harper himself, stated that he refused to be responsible for the fall of every sparrow. (AUDIO: The Fearmonger) He once again said he couldn't be held responsible for every sparrow that falls when Death reminded him of the man who died on Yemaya 4. (PROSE: Sleepy)