Swallow

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 planet.

Swallows are adapted to an insectivorous diet, using streamlined bodies and long, pointed wings to give them endurance and maneuverability while hunting for their winged prey.

Swallows build mud nests close to overhead shelter to protect their eggs or young from the weather and from predators, and are notorious for making their nests in barns and the corners of bridges.

They appear in Halo 3, and can be seen on the multiplayer maps Standoff and The Pit (they fly around in the rafters of the latter).