Origin of Birds Debated

Dinosaurs are living birds, nearly all scientists agree, but a debate still continues about when that first early bird glided or flew into the Mesozoic scene.

Paleontologists who study fossils think the first modern birds evolved from dinosaurs about 60 million to 65 million years ago, right about the time most dinosaurs went extinct. But biologists who investigate DNA measure the origin of birds at about 100 million years ago.

Scientists hoped that a new study analyzing all of the available genetic data with new statistical models might narrow the gap, but instead it has reinforced it and definitively put the DNA-dating estimate at 100 million years ago.