The Silent Flight of Owls at Night
The Owl is a fascinating nocturnal bird and one of the quietest flying bird species in the world. The Owl’s ability to keep completely silent while in action is based on the Owl’s unique feather design, which is unlike any other bird species.
The Owl has five different types of specially designed feathers that result in the bird’s silent flight. The first type is Contour feathers, which cover the entire body including the tail and wings. The second type is Down feathers, which are soft and velvety. These feathers trap air and create an insulation layer, which provides the Owl with warmth. The third type of feathers is called Semi-plumes and their role is to fill in any space that is left open between the contour and down feathers.
Bristles are the fourth type of feathers and these are found around the eyes and around the base of the bill. Bristles are small, stiff feathers that have barbs near the base of the feather. The last type of feathers that the Owl has is called Filoplumes, which are fine and almost hair like in appearance with barbs at the end. The other feathers cover the short Filoplumes, which act as vibration and pressure receptors. The Owl also has Filoplumes on its bill and feet, which helps the Owl to react when it touches prey or other objects.
These five feather types assist the Owl in many ways, including flight. But there is one more adaptation that the Owl has, which assists in producing silent flight. The primary wing feathers have “fimbriae” or “flutings” – edges which are serrated and look similar to a comb. Other bird species don’t have this adaptation, so when they fly air moves over the wing surface, creating turbulence and a swishing sound heard by most prey. The Owl, on the other hand, lessens the amount of turbulence experienced with its comb-like feathers. The turbulence is broken down into groups of micro-turbulence, which muffles the sound and gives the Owl its silent flight.
The ability of the Owl to fly silently is imperative to its survival and its ability to catch prey during the quiet nights. Its silent flight reduces the noise that the Owl and the prey can hear and allows the Owl to hear and locate its prey and capture it with stealth.