ANATOMY OF BIRDS
Bird Wings
Bird Bone Structure
Bird Feathers
Bird Pectoral Muscles
Bird Sternums
Bird Leg Bones
Bird Perching Bones
Bird Pelvic Bones
Bird Vertibrae
Bird Scull Structure
Woodpecker sculls
Bird Beaks
ANATOMY OF BIRDS
GEOGRAPHICAL DISTRIBUTION
MIGRATIONS OF BIRDS
CLASSIFICATION OF BIRDS
LIZARD-TAILED BIRD
AMERICAN TOOTHED-BIRDS
THE OSTRICHES
THE RHEAS
EMEUS AND CASSOWARIES
THE TINAMOUS
THE KIWIS
THE PENGUINS
LOONS AND GREBES
ALBATROSSES & PETRELS
STORK-LIKE BIRDS
GOOSE-LIKE BIRDS
FALCON-LIKE BIRDS
FOWL-LIKE BIRDS
CRANE-LIKE BIRDS
PLOVER-LIKE BIRDS
CUCKOO-LIKE BIRDS
THE ROLLER-LIKE BIRDS
SPARROW-LIKE BIRDS
Birds and Birding's Guide to:
Watching THE ANATOMY OF BIRDS
Bird Bone Structure
This possession of characters in common with reptiles is why it is considered that if birds have not been directly derived from reptiles, they have had a common origin. From the strong resemblances between birds and dinosaurs it was long thought that these reptiles were the parent stock of birds, but this theory has been practically abandoned.
Professor Seeley has thought that the resemblances between birds and pterodactyls was more than superficial, but he stands practically alone in this view, I the most commonly accepted working theory being that birds and dinosaurs have had a common ancestry.
The extent to which the skeleton of a bird is permeated by air usually bears a direct and apparent ratio to its mode of life. Thus the Condor and other soaring birds, such as the Frigate-birds, Cranes, and Screamers, have very lightly built skeletons, and Ducks and other water fowls have the cavities of the long bones filled with marrow, while the bones of the strictly aquatic Penguins are filled with bony tissue.
That the lightness of the skeleton does not necessarily appear in connection with the power of flight is shown by the Hornbills and especially by the larger species, for in these birds of heavy, lumbering flight, the air penetrates to the very tips of the toes. On the other hand, in birds like the Condor and Frigate-bird this pneumaticity, or presence of air in the bones, is believed to aid in oxygenizing the blood and in adjusting the air pressure when a bird descends rapidly from a great height. It may also be connected with lessening the sudden shock that takes place when a Gannet or Brown Pelican plunges headlong into the sea.
It is usual to commence the description of a skeleton with the skull, but while the skull is of the utmost importance to the systematist, it is a complicated structure whose topography is by no means easy to understand, and whose numerous parts bear equally numerous and unfamiliar technical names. So we may slight this, leaving it to be briefly described later on, and begin with the wings, which, next to the feathers, are the most obvious features of a bird.
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