This patch moves the gaia/fauna_hawk.xml template to birds/buzzard.xml, because according to the relevant forum post, our hawk is actually a common buzzard (Buteo buteo).
Birds do not inherit from template_gaia.xml, do not provide any resources, and do not interact, do not even have <Identity>, therefore they don't really belong in the gaia/ folder. A separate birds/ folder makes sense (cf. rubble/, territory_pulls/) and allows for future additions (eagles, falcons, hawks, vultures, etc.).
Apply the patch, then run the following line to adjust all map files:
find binaries/data/mods/public/maps/ \( -name '*.js' -o -name '*.json' -o -name '*.xml' \) -print0 | xargs -0 sed -i 's,gaia/fauna_hawk,birds/buzzard,g'
See also D2774.