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 Sternums
The members of the Auk family fly somewhat heavily, owing to the small size of their wings, but as these are used for flying under water as well as above it, the breast muscles and sternum are large. For the same reason the Penguins, which do not fly at all, have a large sternum, since they swim entirely with their wings, presenting in this respect an analogy to the eared seals, which swim with their fore limbs.
The keel of the sternum is very much reduced and the body of the sternum greatly shortened in birds which sail, this mode of flight involving the expenditure of comparatively little muscular energy. The Albatross has a small breast-bone, and the Frigate-bird smaller still, and these birds are those which fly with the fewest movements of the wing. On the other hand, birds that fly by strokes of the wings have large breast muscles and a correspondingly large sternum, these reaching their maximum in the Hummingbirds, whose skeleton when brought up to the size of a Pigeon is seen to be very powerfully built. The Pigeon, by the way, exhibits the development of the sternal keel for powerful flight.
The front part of the sternum bears the coracoids; the ribs are attached to its sides, while the body of it supports the viscera. In all water birds the breast-bone, is long, corresponding to the long bodies of these birds. The hinder portion of the breast-bone may be entire, perforated, or notched, the notches being two or four in number, reaching their extreme in the fowls in which the body of the sternum is very small and the lateral processes extremely long and slender.
The front of the breast-bone may bear a projecting process, or”manubrium,”and this may be developed from the inner face of the bone, spina interna, or outer, spina externa, at the region of the keel. The manubrium may be a spine (Curassows), or low projection (some Owls), while the extreme development is found in the long”Y”-shaped process so characteristic of the Passeres, the Woodpeckers coming next in this respect. These characters are apparently not associated with any corresponding modifications in the habits of birds, and are, therefore, of great importance in determining the affinities of various groups.
On either side of the breast-bone are little prominences to which the ribs articulate, and in many birds these articulations are found well forward and on a triangular-shaped process, termed the costal process.
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