Vulture

Vultures are scavenging birds of prey that live off the carrion of other dead animals.

Background
They can be seen flying above most settlements in the Capital Wasteland, like Megaton, Temple of the Union, and Evergreen Mills and can also be seen in the sky in New Vegas. Vultures survived the Great War and its many nuclear blasts, and do not appear to have been affected by the radiation at all, uncommon but not unheard of amongst the wild animals.

Fallout 3 and Fallout: New Vegas
Vultures circle around certain areas that contain some degree of notability, such as Megaton, Old Olney, and the alien crash site.

Fallout 76
The body of a large, mutated vulture can be found pinned to Seneca Rocks.