11/10/2019

Birds General characters, classification and flight adoptation (Theory)


General Classification of birds
    Phylum:                   Chordate  -     Presence of notochord in embryonic condition.
    Sub Phylum:            Vertebrate – Presence of vertebral column
    Division                   Gnathostomata – Presence of Jaws
    Class:                       Aves

General characters of birds
1.     Presence of feather is the unique characteristics of birds
2.     Fore limbs are modified in to wings
3.     Wings are used in flight.
4.     Hind limbs are power full and with claws used for bipedal movement.
5.     Warm blooded animals.
6.     Body is divisible into head, neck, trunk and tail.
7.     The bones are spongy and  hollow I.e. pneumatic bone
8.     The modern birds have no teeth in jawas.
9.     Skull is monocondylic.
10. Tail is supported by compound caudal vertebrae called pygostyle.
11. Tail is used to change direction during flight.
12. In fore limb carpals and metacarpals are united to from carpo-metacarpas.
13.  In hind limb tarsal  and metatarsal unite to form tarso-metatarsus.
14. To store food bird hve well developed crop chamber.
15. Stomach is divided into glandular proventriculus and posterior muscular gizzard.
16. Respiration by lung.
17.  Lung is surrounded by non-distensible 9 air sacs.
18. Lung and air sacs meant for double respiration.
19. Heart is four chambered.
20.RBC are nucleated, oval and biconcave.
21. Vocal cords are absent.
22.Syrinx is sound producing organ.
23. Kidney is meta-nephric consist of three lobes.
24. Urinary bladder is absent.
25. Presence of cloaca.
26. Eyes are well developed . vision is monocular.
27.In eye presence of comb like pectin.
28.Brain is well developed.
29. Cerebellum consists of three lobes.
30.  13 to 16 bones of pelveic region are united to form synsacrum.
31.  Clavical bone unite to form  ‘V’ shaped forcula.
32.  Sternum is broad keel like to which muscles are attached.
33.     Sexes are separate. Sexual dimorphism is indistinct.
34.    Fertilization is internal
35.   Birds are oviparous.
36.  12 pair of cranial nerves. 





Order Falconiformes  Eg.  Hawks, eagles, falcons

1.      These birds are carnivorous.
2.      Gregarious bird.
3.      They are diurnal raptorial birds, birds of prey.
4.      Beak or bill is sharply pointed, curved.
5.       The margins of the beak are sharp.
6.      Beak is adopted for piercing and tearing the animal flesh.
7.      The toes are strong and power full with 4 toes. Three toes directed forward    
       and  1st to directed backward.
8.      The toes are terminated with sharp claws.
9.      Lower surface of toes is rough for capturing prey.
10.  Flight is power full and long.  
11.  Sexes are more of similar in plumage but males are smaller in size than female.


Order Galliformes  Eg.  Fowl, Peafowl,. Pheasants, Old World quail, grouse, turkey etc.
1.      These are terrestrial birds often hunted as game birds.
2.      They are gregarious
3.      No power full flight.
4.      Feet are long with four toes. 3 toes facing front and 1 toe directed backword.
5.      Beak or bill is short and weak adopted for eating seeds (Grainivorous  beak) .
6.      Feet are adopted for scratching.
7.      Gizzard is large and muscular.
8.      Intestinal caeca are large.
9.      Keel is well developed.
10.  Well developed after shaft.
11.  Tarsal spur are present in many species is sexual dimorphic characters.
12.  Beautiful plumage is present in many species.
13.  Flight is power full but short.

Order Columbiformes  Eg. Pigeons and Doves
1.      These birds are with small head and having wide range of plumage and colors.
2.      They are gregarious bird.
3.      They feeds on grain and  insects.
4.      The hind limbs are short with reticulate scales.
5.      Beak or bill is weak with fleshy cere at the base of the bill.
6.      They have large crop.
7.      During breeding season inner lignin of crop produces substance known as “Pigeon milk” which is fed to young ones.
8.      Feathers are without aftershaft.


Order Psittaciformes  eg. Parrots, Parakeet
1.      They are feeds upon fruits (frugivorous).
2.      They are gregarious.
3.      The colour of feather is green, red, yellow, blue, etc.
4.      Beak is stout and hooked.
5.      Fleshy cere present at the base of beak.
6.      Upper beak or mandible is movable.
7.      The toes are short.
8.      the toes are zygodactyls modified for climbing on stiff vertical tree trunk.
9.      Scales are present on legs.



Order Passeriformes  Eg. Perching Birds such as sparrow, house crow, robin etc.
1.      This is the largest order of birds comprising over half of the known bird species of the world.
2.      They also include song birds.
3.      They are smaller to medium sized birds.
4.      Beak is weak adopted for variety of food, either granivorous or frugivorous
5.      Bipedal movement.
6.      Toes are slender adopted for perching the twig or any kind of such support.

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