Swallow

From Halopedia, the Halo Wiki

There is more information available on this subject at Swallow on the English-language Wikipedia.

Swallows are a species of bird native to Earth, believed to have originally evolved in Africa. Africa maintained the greatest diversity of swallow species, though today they are common around the planets continents.

They appear in Halo 3, and can be seen on the multiplayer maps Standoff, Ghost Town, and The Pit, where they fly around in the rafters.