280 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



eggs, which are five to six inches long and nearly as thick, 

 are laid naturally in shallow hollows scooped out in the sand 

 of the desert, and the hot sun and the male birds do most of 

 the incubating. The young hatch in from seven to eight 

 weeks, and can run about immediately. 



Ostriches used to be hunted and killed for their feathers, but 

 since the discovery that they can be reared in confinement and 

 a superior quality of plumes thus obtained, their hunting has 

 been given up. They have been domesticated in South 

 Africa since about 1865, and now about half a million tame 

 birds exist there. The present annual value of the ostrich 

 plume output is about $10,000,000. Good average birds will 

 produce $50 worth of feathers a year, and are worth from 

 $700 to $1000 a pair. The plumes grow on the rudimentary 

 wings and tail, and the plucking does not hurt the birds in any 

 way. 



Water and Shore Birds. The typical water birds include the 

 order Pygopodes, or loons, grebes, auks, etc. ; the Longipennes, 

 or gulls, terns, petrels and albatrosses; the Steganopodes, or 

 cormorants, pelicans, and boobies; and the Anseres, or swans, 

 geese and ducks. Among these the cormorants and gulls 

 are of some special use to man as scavengers along the sea- 

 shore, the gulls especially doing much to rid harbors of refuse 

 thrown overboard by the ships. But it is among the Anseres 

 especially that are found the water birds that interest the 

 economic zoologist particularly. The order includes about 

 sixty North American species, of which three are swans, 

 sixteen geese, and the rest ducks. In all, the bill is more or 

 less flattened and is also lamellate, i.e., furnished along each 

 cutting edge with a regular series of tooth-like ridges. The 

 feet are webbed and the legs short and set far back on the body, 

 an adaptation for effective swimming. The food consists of 

 roots and seeds of plants, worms, insects, small molluscs and 

 even small fishes, and only in occasional instances, as in the 

 invasion of grain fields by geese, are the food habits likely to 

 cause loss to man. 



On the other hand, both geese and ducks are among our most 

 abundant and largest game birds, and certain species, such as 



