This is, as the name suggests, the largest hummingbird of all, more than twice as large as the second largest. In hummingbird measures, weight and length are enormous: 0.6-0.9 oz and 9.1. in tall. In the picture you can distinguish the white eye-ring and the light bill, which is about the same length as the rest of the head. Due to its unusually long wings, this species can actually perform gliding flights, something virtually impossible for other hummingbirds. Because of its relatively high calorie requirements, it can also enter a kind of hibernation when food is scarce, with a greatly reduced body temperature - and yet be alert if something threatens it.