[electric guitar riff] Birds are descended from a group of dinosaurs called theropods Which includes the mighty T Rex. However Birds are not dinosaurs. Birds evolved from theropods millions of years ago Birds have a sense of smell that is about as good as that of a dog And much better than that of a human. Some birds Like kiwis and vultures Have an especially acute sense of smell While others Like songbirds Have a poor sense of smell Most birds have at least two vocalizations a song And a call [bird call] (squaaaak) Birds have specialized vocal organs that allow them to make multiple sounds at once Some birds Like the lyrebird and the nightingale Can sing incredibly complex songs While others Like the crow Are known for their calls [melodic interlude, electric guitar solo] Some birds Like pigeons Use the Earth's magnetic field to navigate. They can even sense slight changes in magnetic fields. Scientists are not entirely sure how birds do this But some researchers suspect it has to do with specialized photoreceptors in the eyes (photoreceptors in the eyes) (photoreceptors in the eyes)