1. Sonam Tshering Tshering leki Sherab Chophel
Birds
Sonam Tshering
Tshering leki
Sherab Chophel

2. Outline topics 1. special features (characteristics of birds)
2. secret mechanism in birds
3. features that catch aerial mode of life

3. Special features of birds
Birds are unique. In the animal kingdom birds have two reasons for being special. First, all birds have feathers. And second, all birds live in a hurry.
They breathe faster than any other animal. Their heart beats faster, and their body has high temperature and metabolic rate. Birds have a backbone. Young.J.Z. the life of vertebrates(page;323)
Birds are warm blooded.
Birds lay eggs(oviparous) and defend themselves with a bill or a beak. All birds have wings, but not all birds fly.
Air sac are present.
Four chambered heart.
Fore limbs adapted for flight and hind limb for walking.
Fertilization is internal. (from sir’s note)

4. Beaks and Feet bird beaks
The beak or bill of a bird is another unique feature. A bird does not have a heavy jaw bone and teeth, but a lightweight beak. The shape of a bird's beak varies with the type of food it eats.
bird beaks
All birds have 2 legs and 2 feet. On the ground most birds get around by walking, hopping or climbing. The shape of the feet and legs is different for each type of bird. It is dependent upon use and function.
bird feet
The majority of birds have 4 toes on each foot – one of them points backwards. Climbing birds have two toes pointed to the back to give it more grip.

5. Secret mechanism
Birds are the only animals with feathers. They weigh very little , but birds could not live without them. They help them fly, keep them warm and keep rain and snow away from their skin.
A feather is made up of a central shaft that is very stiff. The vanes on both sides are made up of thousands of tiny barbs.
One of the things that really helps birds to be able to fly is that they are lightweight.
Birds are more lightweight than other creatures because they have special hollow- like bones, and beaks that weigh much less than jaws! Birds also have feathers, which help them to catch the air that keeps them in flight!

6. The bones that birds have are also made for lightness
The bones that birds have are also made for lightness. The bones they have are hard but thin. The powerful flying birds have medium weight skeletons. Birds that don't fly have the heaviest skeleton. In birds many bones are fused together. In this way not as many muscles are needed. The biggest muscles a bird has are its flight muscles. These are very strong because they have to raise the entire body into the air.
The structure of a bird's eyes is very special. Birds have 3 eyelids. The actual image a bird sees depends on the placement of the eyes. The eyeballs of birds are flatter than those of humans. And the retina of a bird's eye is 2 times as thick as a man's. A sparrow hawk can see 8 times more clearly than man.
Hearing is another sense that is strong in birds. The ears not only hear well but are used for maintaining balance. This is critical during flight.

7. Basic mechanics of bird flight
Lift
The fundamentals of bird flight are similar to those of air craft. Lift force is produced by the action of air flow on the wing, which is an air foiled. The lift force occurs because the air has a lower pressure just above the wing and higher pressure below.
Gliding
In gliding flight, a bird's wings deflect air downward, causing a lift force that holds the bird up in the air.

8. Flapping
The wings flap with an up-and-down motion. When the bird flaps its wings, the feathers on the wing act like a propeller, the low pressure area of the feather is at the front of the wing.
Drag
When a flying bird wants to slow down in speed or wants to land they use drag by spreading their tail and lowering there feet or if landing they push there body onto the ground, when the wings are lifted upwards, secondary flight feathers also help the bird to lift. (

9. Internal Power System
A large bird burns extra energy taking off and a small bird uses extra
energy keeping warm. So they both need to be well designed for supplying
energy to their bodies, while maintaining lightness. Birds are warm blooded
animals. They must have extra power to keep a constant body temperature.
Birds have a natural way to solve this power problem. All the inside organs of
a bird run at high speed. This makes for high energy, but shortens the life span of the bird.
The kinds of foods eaten by birds must be "high-octane". These foods are
high in calories.

10. To create energy from the foods they eat, birds must burn them up
To create energy from the foods they eat, birds must burn them up. This is called combustion and oxygen is needed to do this. Oxygen is taken into the body through the lungs where it passes into the bloodstream. Birds need a very fast system to supply the energy they need. Also, in birds there are air sacs next to the lungs. They never run out of breath. The lungs of birds work faster than ours. Birds fly into breath. The heart pumps all the blood through the system. A bird's heart beats much faster than other animals. This makes the blood travel through a bird in seconds. Because of this fast blood travel, a bird's body temperature is 7 or 8 degrees higher than a mans.

11. Features that captures aerial mode of life
Streamlining body: lesser resistance while propelling in the air
Centralization: central of gravity is well adjusted below the wings. Thus helps to balance the streamlined body.
Lightness and rigidity: must be light and strong enough to support the external forces.
Sustain the power of flight: There should be continued supply of energy for mechanical action of flight.
Stearing and balancing: Big or small adaptation in their entire body of the animal contributes for successful adaptation

12. References
Retrieved from birds-01.html on 10th May, 2011 by Sonam Tshering
Retrieved from on 5th May, 2011 by Sherab chophel
Retrieved from on 5th May, 2011 by Tshering Leki
Young.J.Z. The life of vertebrates (page;323)