NESTS AND NEST-BUILDING IN BIRDS 171 



of defence if the prisoner is attacked. At another extreme we 

 find the tree swifts (Macrodipteryx) , of India and Japan, making 

 the smallest nests, in proportion to the size of the builder, known. 

 In one species indeed (M. comatus), it is just large enough to 

 frame and hold the single large egg, but thin as " parchment," 

 and so frail as to be unequal to bear the weight of the builder; 

 accordingly this bird, when incubating, sits over rather than 

 on her nest, resting her feet on the twig to which her diminutive 

 " egg-cup " is attached. Such a nest can afford little protec- 

 tion to the young, and none whatever to the adult. 



A good instance of protection secured mainly through the 

 fighting and guarding instincts of the adult is afforded by the 

 American kingbird; though dull black above and white below 

 these flycatchers are much in evidence about their nests on 

 account of their bold aggressive natures. They build not onh' 

 open but highly conspicuous nests, often placing them on a 

 dead branch, ten or fifteen feet from the ground, and they lay 

 white, boldly spotted eggs. Few of our birds develop the guard- 

 ing and fighting instinct to a higher degree, the male in partic- 

 ular, which never hesitates to assail any marauder which enters 

 his premises. From his swift attack and fiery temper both hawk 

 and crow are quick to beat a retreat. The kingbird seems to 

 advertise its open nest, and because of its pugnacity, it can 

 perhaps afford to do so. 



In many of the eastern species of Icterus both sexes are equally 

 brilliant, but in our Baltimore oriole the female is more quiet in 

 dress than her firebrand of a mate. It is improbable that this 

 oriole would be any less protected when brooding eggs or young 

 if she donned a gayer dress, or that she would be any safer at 

 this time were the nest canopied, or completely concealed from 

 view both from above and below, for in this instance the great 

 element of protection lies in the position of the nest, in relation 

 to all the instincts of the adult, and in spite of certain actions 

 of the young. Their common method of stringing their nests 

 to small, pendent, swaying twigs, and often at a considerable 

 height, renders them practically immune from most attacks of 

 cat, squirrel, snake, jay, or crow. That it is the inaccessible 

 position of the elastic purse-shaped nest that protects the young 

 oriole is shown by a trait which develops a little later. When 

 about twelve days old these young begin to call loudly, at fre- 



