During the teleportation mishap in the Half-Life 2 chapter 'A Red Letter Day', Gordon is first sent into the Wasteland, which is filled with crows, one of which gets caught in midair by Lamarr.Crows (npc_crow) are found in City 17, Ravenholm and the Outlands.There are three known types of birds in Half-Life 2 and its episodes: the pigeon, the crow and the seagull, although many other types of birds (such as woodpeckers or miscellaneous birds of prey) can be heard in the Outlands.Civil Protection officers and Overwatch Snipers can be seen shooting them from time to time, and Xen creatures attack them occasionally as well. As with most NPCs, birds can be killed.

No explanation of this particular survival is given in-game.

With the humans, birds are the only Earth creatures seen during the Combine occupation.

In the non- canonical CTF mode of Opposing Force, Snarks are replaced by penguins with a grenade attached to their backs, serving the same purpose - just with a more explosive result. Sound file names suggest they consist of hawks and quails. Birds can be heard outside of Black Mesa.

Half life 2 prefabs