160 million years ago: earliest birds.
The scientific consensus is that birds evolved from carnivorous dinosaurs around 165 to 155 million years ago. The famous English biologist Thomas Henry Huxley, better known as Darwin’s Bulldog, was the first one in the nineteenth century, to propose this idea.
To say that birds are dinosaurs is equivalent to say that humans are mammals.
The earliest bird fossil is Archaeopteryx litographica, dated from the Upper Jurassic, 168 million years ago, and found in a limestone quarry near Solnhofen, Germany. The first specimen was discovered in 1861, just around the same time when Darwin published his Origin of Species. He even he knew about this discovery. Since then, ten more specimens have been found.
Archaeopteryx was about the size of a crow, with short, broad wings and a long tail. Its feathers were similar to those of living birds, but had jaws with sharp teeth, three fingers ending in curved claws and a long bony tail. Some of its features resembled those of contemporary birds, like feathers, but it had teeth and a long tail like all dinosaurs.
All these characteristics, differing from modern birds, provide evidence that birds descended from dinosaurs.