Our friend from Sesame Street may be a big bird, but he’s tiny compared to some real birds that have roamed the earth in the past. Here are a representative few of these big birds we will never see alive again. In some cases, that’s a comforting thought.
There were four or five species of the bird genus Gastornis that lived in North America, Europe, and Asia 55 to 40 million years ago. The North American bird was previously known as Diatryma before it was reclassified. Gastornis were big flightless birds, the largest species being Gastornis giganteus, which grew to 6.5 feet tall. But they weren’t anything to be afraid of -unless you were a plant. Its powerful beak was used to crush seeds and fruit. That’s right, this bird was a vegetarian! However, it could well have used that beak as a defense against attackers. The top picture is a 1917 illustration of what Gastornis may have looked like.
2. Pelagornis Chilensis
Just a few years ago, it was thought that Pelagornis chilensis had the largest wingspan possible for a bird at 17 feet. P. chilensis lived in Chile 5 to 10 million years ago, where it skimmed the ocean surface for fish. That large wingspan was necessary to carry a 64-pound flying body. It is classified as a pelagornithid, or bony-toothed (“pseudotooth”) bird. Some other species of pelagornithids may have survived long enough to have been seen by humans.
3. Pelagornis Sandersi
The idea that 17 feet was the upper wingspan limit for flying birds was shattered in 2014. Pelagornis sandersi is largest flying bird yet found, with a wingspan of up to 24 feet! The fossil was found in Charleston, South Carolina in 1983, but it was kept in storage for thirty years before anyone studied its measurements. And now that we know how big this pseudotooth was, the mystery that remains is how it ever achieved liftoff with such long wings. It’s possible that the bird jumped off seaside cliffs.
Andalgalornis steulleti was a Phorusrhacid that stood 4.5 feet tall and weighed about 90 pounds. Phorusrhacids, the 18 species of the family Phorusrhacidae, are commonly called “terror birds,” because they were huge apex predators during the Cenozoic era. Andalgalornis lived in Argentina around 6 million years ago. Its skull was distinctively thin as seen from above, but its narrow beak appears huge from the side. Andalgalornis had a rigid-boned skull that gave it a powerful bite compared to other birds with more lightweight construction.
The largest terror bird was Kelenken guillermoi, which lived 15 million years ago in Argentina. Kelenken stood somewhere between seven and ten feet tall. Its lower leg bone is 45 centimeters (18 inches), and it had a skull 71 centimeters (28 inches) long with a 45 centimeter beak. This flightless bird weighed around 500 pounds and killed its prey with its massive beak.
6. Titanis Walleri
The terror bird Titanis walleri became an American Phorusrhacid as a result of species moving over the Isthmus of Panama about three million years ago. Its fossils have been found in Texas and Florida. T. walleri lived from 5 to 2 million years ago. This bird stood eight feet tall and weighed over 300 pounds. The species, in a fictionalized form, stars in the 2006 novel The Flock by James Robert Smith.
7. Haast’s Eagle
Haast’s eagle is extinct, but not exactly prehistoric. Scientists believe the youngest fossils may be only 500 years old, which means the eagle’s extinction was probably due to human hunting of the eagle’s main prey, the moa. Haast’s eagle (Harpagornis moorei) was native to New Zealand, and was the largest eagle that ever lived. The female, larger than the male, weighed 10–15 kilograms (22–33 pounds) and had a wingspan of 8-10 feet. The species had a relatively short wingspan for its weight.
Speaking of New Zealand, it was once home to an extinct bird genus that actually resembled Sesame Street’s Big Bird. Dinornis, or the giant moa, was the main food source of Haast’s eagle until it was hunted to extinction by the Māori in the 15th century. The female of the species Dinornis robustus stood 12 feet tall and weighed over 500 pounds, possibly up to 600 pounds! New Zealand had no mammals before human settlers arrived from Polynesia, and so they thrived for 40,000 years, despite Haast’s eagle.
With an estimated wingspan of 23 feet, Argentavis magnificens is the only extinct bird found so far that can approach Pelagornis sandersi in wingspan. And we have more fossil specimens of the “magnificent bird of Argentina.” It existed more recently than many of the birds on this list, living around six million years ago. A. magnificens weighed between 60 and 80 kg (140-180 pounds), so it is a mystery how it managed to take off, but it is inferred that the bird soared on thermal currents instead of flapping its wings. Argentavis ate carrion instead of swooping down on live prey. A. magnificens is related to modern vultures.