My turn, y'all. I'm gonna follow the rules of birds and how they're introduced in-game, so I will omit any birds that aren't primarily ground dwellers:
- Arctic: Rock ptarmigan
- South America: Greater rhea
- Australia: Australian brushturkey
- Aquatic: Atlantic puffin
- Southeast Asia: Victoria crowned pigeon
- África: Helmeted guineafowl
- North America: Wild turkey
- Europe: Capercaillie
- Wetlands: Mallard
- Conservation: Whooping crane
- Twilight: Black-crowned night heron
- Grasslands: Greater roadrunner
- Tropical: Scarlet ibis
- Arid: Secretary bird
- Oceanía: Black swan
- Eurasia: Red junglefowl
- Barnyard: Muscovy duck