The Bluebird 49 



their range every winter, those who do not being but a handful in com- 

 parison. 



"What does this great downward journey of autumn mean? " you ask. 

 What is the necessity for migration among a class of birds that are able to 

 find food in fully half of their annual range? Why do birHs seek extremes 

 ior nesting sites? This is a question about which the wise men have many 

 theories, but they are still groping. One theory is that once the whole 

 country had a more even climate and that many species of birds lived all the 

 year in places that are now unsuitable for a permanent residence. There - 

 iore, the home instinct being so strong, though they were driven from their 

 nesting sites by scarcity of food and stress of weather, their instinct led them 

 back as soon as the return of spring made it possible. 



Thus the hereditary love of the place where they were given life may 



underlie the great subject of migration in general and that of the Bluebird's 



home in particular. 



Before more than the first notes of the spring song have 

 The Bluebird i i • i i- m i • i i i j 



^ „ sounded m the distance, Bluebirds are to be seen by twos and 



at rlome 



threes about the edge of old orchards along open roads, where 

 the skirting trees have crumbled or decaying knot-holes have left tempting 

 nooks for the tree-trunk birds, with whom the Bluebird may be classed. 

 For, though he takes kindly to a bird -box, or a convenient hole in fence- 

 post, telegraph pole or outbuilding, a tree hole must have been his first home 

 and consequently he has a strong feeling in its favor. 



As with many other species of migrant birds, the male is the first to 

 arrive; and he does not seem to be particularly interested in house-hunting 

 until the arrival of the female, when the courtship begins without delay, 

 and the delicate purling song with the refrain, "Dear, dear, think of it, 

 think of it," and the low, two-syllabled answer of the female is heard in 

 every orchard. The building of the nest is not an important function, — 

 merely the gathering of a few wisps and straws, with some chance feathers 

 for lining. It seems to be shared by both parents, as are the duties of hatch- 

 ing and feeding the young. The eggs vary in number, six being the maxi- 

 mum, and they are not especially attractive, being of so pale a blue that it is 

 better to call them bluish white. Two broods are usually raised each year, 

 though three are said to be not uncommon; for Bluebirds are active during 

 a long season, and, while the first nest is made before the middle of April, 

 last year a brood left the box over my rose arbor September 12, though I do 

 not know whether this was a belated or a prolonged family arrangement. 



As parents the Bluebirds are tireless, both in supplying the nest with in- 

 sect food and attending to its sanitation; the wastage being taken away and 

 dropped at a distance from the nest at almost unbelievably short intervals, 

 proving the wonderful rapidity of digestion and the immense amount of 

 labor required to supply the mill inside the little speckled throats with grist. 



