The Anatomy of Aviation

Indian Roller in display at Sakteri,Haryana

Birds are masters of the air. Other animals can           fly, but none can match the sheer speed, agility,   and endurance of birds. Qualities which have been  refined by millions of years of evolution. We all know how birds fly, they have hollow and light bones, they have a streamlined body and they have feathers to push air back and take flight. We must acknowledge that all these facts are the most important ones, yet there is more to the art of  flying in birds.

 Flight is the most distinguished feature of birds  which differs them from other animals. Flight helps them while feeding, breeding, migrating, fleeing. The Indian Roller even uses its amazing flight to impress its partner for breeding by performing aerobatics and stunts in the air. Bird flight is a very vast topic and different birds have different flight patters and techniques. Some birds use their wings for gliding, some for hovering, some for soaring and so on. Nature has perfectly crafted flight patterns to different birds as per their needs.

All basic bird anatomy starts from a prehistoric creature known as the Archaeopteryx, which is considered to be the first bird ever. Its feathers only supported gliding and it had woodpecker like hand and feet which helped it grab onto trees. Today 150 million years after the the transition from dinosaurs to birds, we have over 10,500 species of birds around the world, all with distinct features, different colours, calls, flight patterns and behaviour.

The basic concept of flight lies in lift and drag. Lift is produced by the action of air flow on the wing, which is an Airfoil . The airfoil is shaped such that the air provides a net upward force on the wing, while the movement of air is directed downward.

Aerodynamic drag is the force which acts opposite due to which the bird exerts energy and pressure to the flight.

The shape of the wing of a bird is also very important for flight and there are many types of wing shapes. If the wing's shape is not balanced properly i.e if one of the wing is longer or heavier than the other, birds will not be able to fly at all, just like a plane crashing if the if one of its wing is only an inch longer.

Different birds have different wing shapes for different needs. 
Hummingbirds and sunbirds have short and triangular wings which are ideal for fast wingbeats while Eagles and vultures have Broader wings to catch rising air currents. I saw this phenomenon for the first time in Morni, Haryana from an observation point which was at a great height. At that point we saw a Himalayan Griffon Vulture which flew at a point and then suddenly gained a great height.When the vulture gained a great height, it flew across the whole land in a straight path and scanned for prey. After a while several more vultures stormed the same point and did the same thing. Mr. Daman, who was with us that afternoon and is an aeromodelling instructor in the Air Force told us that the vultures are catching warm air currents called thermals to get a better view. These thermals are present only at some points, and when the warm air which rises up, raptors identify it and it basically acts a lift for them to get to a higher level. It was very satisfying and fun to watch raptors catching thermals at different locations.

Himalayan Griffon after catching a thermal.

Birds also have different flying patterns. You may have seen that Cormorants and ducks during flight use rapid and regular wing beats while when you see a Swallow or Bee Eater, they randomly glide and flapp as they hunt insects in mid air. The different types of flight include: Gliding, Hovering, Flapping, Bounding, Random flight which are all self explanatory. Several times I have seen birds such as Kingfishers, Kestrels, Black Winged Kites and Short Toed Snake Eagles hover in mid air over their prey. They are able to do this by flying upwards just fast enough push against gravity against a wind current.

Take offs and Landings also have to be very precise. Birds such as Ducks, Cormorants, Herons and all other waterfowl have heavier bodies and have to exert more energy and pressure than other birds. Many waterbirds such as ducs and cormorants take a run-up and make the water their runway before taking off, while some birds just launch themselves.

Black Eared Kite at take off.

Landings have to be very accurate. If the bird does not land properly and aims for the wrong place, it will go crashing down into the ground. Birds extend their feet just like a plane unfolds its landing gear and perfectly co-ordinate their wings with slowing down a halting. Hence, almost all of our Aerodynamic Vehicles have been inspired from the flight and flight structures of birds.

Black Kite balancing before landing.

The tail also plays a major role in flight and gives direction to the angle on which the bird flies. In birds such as Bee-Eaters, the tail helps them take extreme turns in mid air when they are trying to catch insects and when this happens they also make a small "krrrk" sound if you observe closely.

A Blue Tailed Bee-Eater in flight.

Well, this was all I could observe about the flight of birds after 3-4 years of birding.There may be many more concepts and facts about bird flight that I need to learn, but now at least we now that why the birds keep preening their feathers.