Development and Care of the Young 1 73 



dropped at a distance from the nest, while in others they are dis- 

 regarded altogether. At an early period of development the 

 slightest crack is likely to addle the egg, but unless it is actually 

 broken open it is usually allowed to remain in the nest. Many 

 wild birds will "incubate" stones, or addled eggs, showing in 

 this respect hardly more discrimination than the domesticated 

 hen, and the Great Herring Gull, after wasting much time over 

 a barren egg, will often use it as so much building material in 

 preparing a new nest. 



In one instance I have seen this Gull pick out the soft re- 

 spiratory sac from the shells, and devour it on the spot, a curious 

 and sporadic act, which is probably not confined to this species. 

 It suggests the well-known and useful instinct in many of the 

 higher mammals of eating all such parts as might betray their 

 presence to an enemy. 



II 



BROODING AND FEEDING THE YOUNG 



When the callow young are hatched, brooding is the order 

 of the day as well as of the night, and in some species the young 

 seem to require this kind of protection as much as food. During 

 the first days of life in the nest it is not easy to distinguish a 

 brooding from a sitting bird, but this is not the case when a 

 little later the mother begins to rest her wings over the rim, or, 

 spreading wings and tail stands astride the nest with back to 

 the sun. The young must be protected from heat, cold, and 

 rain, and the instinct to perform this duty is as strong with old 

 birds as that of bringing food. 



Cedar Waxwings and Kingbirds which I have watched, 

 brooded regularly at night, but I have known young Robins to 

 be left alone in the nest. Should the day be cloudy but with no 

 rain, or sunny but not too warm, little or no brooding has been 

 observed among the various species which I have studied, but 

 let the sun bea,t relentlessly upon the young, or the air become 

 laden with moisture, and the faithful mother is promptly at 

 her post. I have seen the Robin brood the young when eleven 



