Hummingbirds, which are tiny, colorful, thin-beaked birds, get their name from the humming noise that occurs when they flap their wings very fast. Some facts: Hummingbirds have 1,000 to 1,500 feathers, the fewest number of feathers of any bird species in the world; they cannot walk or hop, though their feet can be used to scoot sideways while they are perched; An average hummingbird’s heart rate is more than 1,200 beats per minute. In comparison, a human's average heart rate is only 60 to 100 beats per minute at rest; The calliope hummingbird is the smallest bird species in North America and measures just 3 inches long. The bee hummingbird is the smallest hummingbird species in the world and measures 2.25 inches long; Hummingbirds have no sense of smell but have very keen eyesight.