UNIQUE FEATURES OF BIRDS

The birds differ from all other vertebrates in having certain unique characters.
(Characteristics) as follows.

1) Birds are homeothermic (warm blooded) animals their body is covered by feathers which forms an insulator.

2) The epidermal exoskeleton is represented by feathers and a few scales as the legs similar to those of the reptiles.

3) The limbs are modified as wings. The hind limbs are attached forward to balance the weight of the body.

4) The endoskeleton is mostly spongy containing air cavities so that the body becomes light. The bones of the skull undergo early ankylosis . Only the lower jaw, quadrate,
Columella and hyoid are movable. There is only one occipital condyle. The premaxillae are large and form most of the beak. In modern birds there are no teeth.

5) There is a well developed sternum with the keel. In flying birds, the clavides to form well developed and are connected by an interclavicle to form furcula. The forelimb has only three digits.

6) The three metacarps age gused and there are only two separate carpels, other fuse with the metacarpels to form the carpomet acarpus. The thumb is often clawed.

7) In the digestive system, the gullet is dilated into a crop and the stomach is divided into a glandular proventriculum and muscular gizzard. A cloaca is also present.

8) The non exspansible lungs are provided with air sacs which many extend into the bones. The trachea has bony rings. A special vocal organ in the form of syrinx is present

9) The heart is four chambered, the right auriculo-ventricular valve is muscular. There
is only right aortic arch. The renal portal system is not well developed. The red blood corpuscles are oval and nucleated.

10) The brain has large cerebellum and cerebral hemispheres and the optic lobes are laterally displaced. The kidneys are three lobed. There is no urinary bladder.

11) Compared to other animals, birds have the wonderful capacity of adjusting their eyes vary quickly from a distant object to a nearby object.

12) Their ears are too small little holes on either side of the head. As they are covered by feathers, they are not easily visible. However their sense of hearing is very sharp and they use it for hunting self protection and mating purposes.


The smallest bird is the bee-humming bird while the largest is the Ostrich which weighs 180 kg.


The fastest of all creatures is the Spain tailed swift. The Ostrich is the fastest bird on legs and has a sped of 80 km/hr. The fastest mountain climber is the Chamois. It can climb 1000 m in 15 minutes. At this rate it can be climb Mount Everest in just over 2 hours.

BIRDS Km/h

Spine tailed Swift 171

Frigate bird 153

Spur-winged goose 142

Red breasted merganser 129

White rumped swift 124

Canvas bouk duck 116

Eider duck 113

Teal 109

Mallard 105

Pintail 105