Birds radiate into the empty sky
The few surviving lineages of ground-dwelling birds expand into most of the orders alive today.
- When
- —
- Duration
- 10 million years
- Known to
- ± 2 million years
- Era
- Paleocene, Cenozoic
Only a handful of bird lineages cross the boundary, and the evidence suggests the survivors were small ground-dwellers rather than tree-dwellers — consistent with a world whose forests had just burned. From that narrow base the group re-radiates fast, and molecular phylogenies show most modern orders separating within about fifteen million years of the impact. Every one of the ten thousand living bird species descends from those few survivors, which makes birds the only dinosaurs left and their diversity a direct consequence of the disaster.