How to Study Birds 57 



only infrequent, but the observations themselves are apt to be inconclu- 

 sive or susceptible of more than one interpretation. 



As an excellent species on which to conduct a series of observations 

 during the mating season, the student is commended to the English Spar- 

 row. What significance have its battles, struttings and general vociferous - 

 ness when it is mating ? 



THE NEST 



Probably less than twenty, possibly not more than ten, per cent of 



,, ,. ^ the eggs laid by birds bring forth chicks which reach 



Mortality of c u x • u r u- i 



, ,^ . maturity, bo great, therefore, is the mortality among birds 



the Nesting , . . . , ' . , ' . ^ , 



o during nesting time that the continued existence of a 



species depends largely upon the degree of success with 



which it encounters the enemies of the young bird in the egg or in 



the nest. 



It will add to our appreciation of birds' resources, and most assuredly 



r. . , to our sympathy with bird -life, if, before studying the nest 



hnemies of , "• ■ ,• r l- j i 



,7- . and nesting habits of birds, we merely mention some of the 



Nesting . , . , • , , , • , 



„. , enemies and dangers which threaten birds at this season. 



They are of two kinds: First, the elements; second, preda- 

 tory animals, including parasites. 



High winds, heavy rains, floods, hail-storms, excessive heat, are among 

 the weather phenomena often fatal to the life of the nest ; while, in 

 this region, chief among the animals that prey upon birds' eggs, or ^^oung 

 birds, are Crows, Jays, cats, squirrels, opossums, minks, weasels, skunks, 

 snakes, and man, who either directly, as an egg collector for the table or 

 cabinet, or indirectly, in mowing fields or otherwise altering birds' nest- 

 ing haunts, has more than won a prominent place among the enemies of 

 the nest. 



With such an array of adverse conditions and relentless foes the bird 



who lives to acquire the powers of adults of his kind may be said to 



have escaped nine -tenths of the dangers to which bird -flesh is heir. One 



J. realizes, therefore, how important it is for birds to select a 



Importance • ■ -u j l x. ■ ■ 1 • , 



^ J site, build a nest, and care for their young in a way which 



of Instincts , , , , • > 1 r . ■ • , , 



has proved to be most desirable for their species; and how 



readily lack of instinct or inability to conform to new conditions may 



mean failure to rear a brood and, in the end, extinction of their race. 



The nature of a bird's nesting site appears to be determined by (i) 



the necessity for protection; (2) habit, whether arboreal, terrestrial or 



p , . aquatic; (3) haunt, whether in woodland, field, marsh, etc. ; 



Selection , . . . 



r o- l4i temperament, whether social or solitary ; \S) conditions 



of a bite , , . . . 



of the young at birth. 



Protection may be secured by hiding the nest, by placing it in more 



