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 Pelvic Bones
In the vast majority of living birds (the Neognathae) the ilium and ischium are firmly united. The pubic bones, the long, slender, lowermost bones of the pelvis, unite posteriorly in the Ostrich, but are free in other birds and are frequently widely separated; they may even be nearly lacking, as in Eagles, in which the hinder portions only remain. The outward flare and generally open character of the pelvis below has to do with the question of room for the passage of the large and brittle egg. Birds while in water birds it is long and narrow, much the same condition being found in flightless birds which run much.
The neck vertebrae of birds are peculiar from the character of their articulations, which are saddle-shaped, concave one way and convex the other, a form termed heteroccelous, and one that allows great freedom of movement in both planes. Theoretically the ball-and-socket joint permits the greatest amount of motion, but in practice this form of joint is usually combined with some arrangement which checks its movements.
Thus in the snake, while there is the utmost freedom of movement from side to side, there is but little play vertically. The neck of the bird is always long and the vertebrae numerous; this is necessary in order that the bird may reach all parts of its body with the tip of its bill, and secondly, that it may obtain food. Thus long legs and long necks go together, or, as in the Sandpipers and Snipe, there is an increase in the length of the bill, while Swifts, Swallows, and Goatsuckers, which capture their prey in mid-air, have short necks. Swans, which do not dive, have much longer necks than diving birds, or Geese, which feed largely on land. The very long neck of the Darter is associated with its habit of suddenly straightening the neck and impaling fish on its sharp bill.
Usually the last two neck vertebrae bear free ribs, these being but the lengthening and freeing of the long processes running backwards from the sides of the front of the vertebras. That these are really ribs may be readily seen in a young Ostrich, in which they are free, but while later on they become united with the bodies of the vertebrae, the last two remain free, although they do not reach the sternum.
The thoracic region of a bird, the body proper, usually consists of a comparatively small number of vertebrae bearing long ribs, the foremost of which are attached to the sides of the breast-bone. Water fowl, like the Loons, Auks, and to a lesser degree Ducks, have the longest bodies, soaring birds the shortest. Several of the vertebrae in the center of the series are fused or ankylosed together to stiffen the body for flight, a free vertebra or two next the pelvis permitting some motion here.
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