This brings us to the game birds — the world-wide tribes of partridges, 

 pheasants, grouse, turkeys, jungle fowls, peacocks and the like — which are of large 

 size, run about on the ground, and are of interest to sportsmen and epicures. With 

 few exceptions these must put forth a large complement of eggs (eight to twenty) 

 in order to bring to maturity enough young to replace the yearly mortality, for the 

 ground-built homes and huddling chicks encounter a multitude of dangers to 

 which birds in trees, or even the small-sized ground-nesters, are not exposed. One 

 exception here singularly favors the rule. The Thibetan Peacock Pheasant inhab- 

 its the heights of the Himalayas, where it has to contend with only three or four 

 nest-robbers, instead of the countless foes that infest the lower jungles; hence its 

 ample breast warms but two eggs. 



The doves and pigeons lay only two eggs, and a few lay but one ; but this 

 seems to be due to the fact that their extraordinary powers of flight render them, 

 as adults, unusual immunity from capture and famine, rather than to any special 

 safety pertaining to their method of nidification. 



Hawks and owls in general have four or five eggs, and as this is about the 

 average number of the small birds on which they largely prey, it seems evident 

 that their chances of life and the difficulty of sustaining it are, on the whole, no 

 less than are met with by their victims. The owls, however, vary much among 

 themselves in this respect; the snowy owls, whose home is in the snowy north, 

 where a nest in the tundra moss is accessible to every marauder, and the burrow- 

 ing owl, whose underground homes are constantly robbed, being obliged to lay 

 twice as many eggs as the remainder of the family in order to overcome the high 

 percentage of casualties due to these unfortunate situations. 



An odd feature in the nidification of some of the Arctic-breeding owls, where 

 the nesting must take place at an unreasonably early and cold date in order to 

 give the fledglings time to reach mature strength before the succeeding winter 

 assails them, is that these birds deposit their eggs at intervals of a week or ten 

 days. In this way the mother can envelop in her plumage and keep thoroughly 

 warm one egg and a callow fledgling at a time, and is assisted, in respect to the 

 latter eggs and fledglings, by the warmth of the older young in the nest. 



This brings us to tribes of little singing birds, with which we started, whose 

 average is about five ; but a few interesting exceptions may be noted. Our whip- 

 poor-wills and nighthawks, for instance, lay only two eggs. These are placed on 

 the ground in the woods surrounded by no nest, and are so precisely the color of 

 the dead leaves that nothing but the merest accident would lead to the discovery 

 by the eye alone. The same is eminently true of the bird itself. None of the 

 almost uncatchable humming-birds needs to lay more than two eggs in order to 

 recruit the ranks of its species to the full quota permitted it in the numerical 

 adjustment of bird life. 



I have gone into this matter somewhat at length, though by no means ex- 

 haustively, because I am not aware that the matter has ever been exploited, and 

 because it embodies a general law or principle. Thus we see that the nest comple- 



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