Birds (class Aves or clade Avialae) are feathered, winged, two-legged, warm-blooded, egg-laying vertebrates. Aves ranks as the tetrapod class with the most living species, approximately ten thousand. Extant birds belong to the subclass Neornithes, living worldwide and ranging in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. The fossil record indicates that birds emerged within the theropod dinosaurs during the Jurassic period, around 150 million years ago. On 31 July 2014, scientists reported details of the evolution of birds from theropod dinosaurs. Most researchers agree that modern-day birds are the only living members of the Dinosauria clade. Modern birds are characterised by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. Extant birds have wings; the most recent species without wings was the moa, which is generally considered to have become extinct in the 16th century. Wings are evolved forelimbs, and most bird species can fly. Flightless birds include ratites, penguins, and diverse endemic island species. Some species of birds, particularly penguins and members of the Anatidae family, are adapted to swim. Birds also have digestive and respiratory systems that are uniquely adapted for flight.
We only see it in one scene in the early Paleocene segment.After the extinction of the dinosaurs, a bird flies over the ground, while the narrator says birds are the last dinosaurs. It was live-acted by a vulture.