Bird

The Bird, also known as the Crow, is a miscellaneous character throughout many Valve titles and parent of Mr. Chubby Beak and other two unnamed chicks.

The Bird plays a minor role during the single player campaign, and returns later during the additional cooperative testing course, Art Therapy as the main antagonist.

Cooperative Testing Initiative
In the Art Therapy testing course,

Other games
Crows resembling the Bird make appearances in various other Valve titles, such as Half-Life 2 and the Left 4 Dead series, as generic npcs.

Half Life 2
Birds can be seen flying or gliding nearby beaches and forests, a similar crow sometimes appears inside City 17.

List of appearances

 * Half-Life 2
 * Portal 2
 * Left 4 Dead
 * Left 4 Dead 2

Trivia

 * All the sound files for the Bird in Portal 2 start with birdbirdbird, probably because in its first appearance, Wheatley shouts 'Bird Bird Bird!'