75% of species died after a 10km-wide asteroid struck 66 million years ago, but surviving birds expanded into niches once held by non-avian dinosaurs, marine reptiles and pterosaurs.
3m-tall terror birds in South America became apex predators for more than 40 million years, while elephant birds in Madagascar and Australia’s 725kg demon ducks took over giant herbivore roles.
1.8m colossus penguins hunted as top ocean predators, and pelagornithids evolved saw-like jaws and wingspans above 7m to dominate aerial soaring niches left by pterosaurs.
Europe’s Gastornis and North America’s Diatryma were long cast as killers, but bone chemistry now points to giant herbivores that later gave way to mammals.
700 to 900 years ago, moas and elephant birds vanished after human arrival, underscoring how long birds ruled post-dinosaur ecosystems before mammals and people displaced them.