Following is the list of Top 10 Heaviest Living Birds as per Consensus Document on the Biology of Populus:
| Rank | Bird | Average Mass | Maximum Mass | Average Total Length |
| 1 | Ostrich | 104kg | 156.8kg | 210cm |
| 2 | Southern Cassowary | 45kg | 85kg | 155cm |
| 3 | Northern Cassowary | 44kg | 75kg | 149cm |
| 4 | Emu | 33kg | 70kg | 153cm |
| 5 | Emperor Penguin | 31.5kg | 46kg | 114cm |
| 6 | Greater Rhea | 23kg | 40kg | 134cm |
| 7 | Dwarf Cassowary | 19.7kg | 34kg | 105cm |
| 8 | Lesser Rhea | 19.6kg | 28.6kg | 96cm |
| 9 | King Penguin | 13.6kg | 20kg | 92cm |
| 10 | Dalmatian Pelican | 11.5kg | 15kg | 170cm |
