64 NORTH AMERICAN BIRDS. 



out from their retreats, and again disappear on the return of severer weather. 

 Later in the season, or early in March, they return and make a permanent 

 stay. 



When well treated, as the Bluebirds almost universally are, they return 

 year after year to the same box, coming always in pairs. The marked atten- 

 tions of the male bird are very striking, and have been noticed by all our 

 writers. He is very jealous of a rival, driving off every intruder of his own 

 species who ventures upon the domain he calls his own. Occasionally the 

 pair suffer great annoyance from vexatious interferences with their domestic 

 arrangements by the house wren, who unceremoniously enters their home- 

 stead, despoils it of its carefully selected materials, and departs. At other 

 times the wren will take possession of the premises and barricade the en- 

 trance, making the return of its rightful owners impossible. 



The song of the Bluebirds is a low warble, soft and agreeable, repeated 

 with great constancy and earnestness, and prolonged until quite late in the 

 season. Just before their departure, late in October, the sprightliness of 

 their song nearly ceases, and only a few plaintive notes are heard instead. 



The food of the Bluebird consists principally of the smaller coleopterous 

 insects, also of the larvte of the smaller lepidoptera. In the early spring 

 they are very busy turning over the dry leaves, examining the trunks and 

 branches of trees, or ransacking posts and fences for the hiding-places, of 

 their prey. In the fall their food partakes more of a vegetable character. 



The Bluebird selects as a suitable place for its nest a hollow in the de- 

 cayed trunk of a tree, or boxes prepared for its use. Their early arrival 

 enables them to select their own site. The nest is loosely constructed of 

 soft materials, such as fine grasses, sedges, leaves, hair, feathers, etc. These 

 are rarely so well woven together as to bear removal. The eggs are usually 

 five and sometimes six in number. There are usually three broods in a 

 season. Before the first brood are able to provide for themselves, the female 

 repairs her nest and commences incubation for a second family. The young 

 birds are, however, by no means left to shift for themselves. The male bird 

 now shows himself as devoted a parent as in the earlier spring he had proved 

 himself an attentive mate. He watches over the brood even after the second 

 family appears and claims his attention. We often find him dividing his 

 cares in the latter part of the season with two broods, and at the same 

 time supplying his mate with food, and occasionally taking her place on 

 the nest. 



The eggs of the Bluebird are of a uniform pale blue, measuring about .81 

 of an inch in length by .62 in breadth. 



In Guatemala is found a local race differing in its lighter under colors and 

 in the greenish tinting of its blue (S. azwrea). The S. sialis is also found in 

 the more open districts of the elevated regions where it is numerous. It is 

 there known as " M azulejo." 



