Of the twelve flying birds, I have chosen five species that would need free-flying but the other seven are species that, although they are kept in aviaries, would not look out of place spending most of their time on the ground. I have also tried to choose species from six continents:
1. Ruppell's griffon vulture (Africa): Desert, Grassland - Critically Endangered
2. African sacred ibis (Africa, Asia): Aquatic, Grassland, Temperate, Tropical - Least Concern
3. Wrinkled hornbill (Asia): Tropical - Endangered
4. Mindanao bleeding-heart dove (Asia): Tropical - Vulnerable
5. Hyacinth macaw (South America): Grassland, Tropical - Vulnerable
6. Scarlet ibis (South America): Aquatic, Grassland, Tropical - Least Concern
7. Bald eagle (North America): Aquatic, Desert, Grassland, Taiga, Temperate - Least Concern
8. Greater roadrunner (North America): Desert - Least Concern
9. Black woodpecker (Asia, Europe): Taiga, Temperate - Least Concern
10. Atlantic puffin (Europe, North America): Aquatic, Temperate, Tundra - Vulnerable
11. Flame bowerbird (Oceania): Tropical - Least Concern
12. Superb lyrebird (Oceania): Temperate - Least Concern
Of the larger ground-based birds, I feel like I had to choose eight species, as there are enough good options to warrant it. Again, I have tried to choose birds from multiple continents:
1. Grey crowned crane (Africa): Aquatic, Grassland - Endangered
2. Southern ground hornbill (Africa): Grassland - Vulnerable
3. Painted stork (Asia) - Aquatic, Grassland, Tropical - Near Threatened
4. Ocellated turkey (South America): Temperate, Tropical - Near Threatened
5. Grey-winged trumpeter (South America): Tropical - Near Threatened
6. Great blue heron (North America): Aquatic, Grassland, Taiga, Temperate - Least Concern
7. Dalmatian pelican (Asia, Europe): Aquatic, Grassland, Temperate - Near Threatened
8. Australian bustard (Oceania): Desert, Grassland - Least Concern