BLUE OR METALLIC BLUE 507 



at San Diego flying out after insects, or skimming the 

 air like swallows, and hovering like hummingbirds. 

 They have a pretty fashion of quivering their wings a 

 moment as if loath to close them. 



Their song is a sweet clear " trually, tru-al-ly," like 

 that of the Eastern species, and a mellow warble. High 

 up in the mountain meadows, where these bits of azure 

 nest, they are usually seen only in pairs, and are fre- 

 quently the only pair in the neighborhood, and here their 

 feeding habits are those of the thrushes once more. 



Both male and female carry material to the old tree 

 which they have selected for a home. Usually the 

 cavity chosen is one excavated the previous year by a 

 woodpecker, but sometimes a natural hole in a dead tree 

 or a crevice about a house is selected. In any case it is 

 nearly filled with dried grass and feathers. Fourteen 

 days are required for incubation, and in this the male 

 often, but not always, shares. When not on the nest 

 himself he brings food to his mate, calling to her in 

 sweetest tones from the outside before entering the door- 

 way. The newly hatched young are of the usual naked 

 pinkish gray type, looking as like tiny new-born mice as 

 birds. On the second day down begins to appear in 

 thin hairs on head and back ; on the fourth or fifth day 

 the eyes show signs of opening ; on the sixth day they 

 open, and the down is well spread over the bodies. . 



Up to this time they have been fed by regurgitation, 

 the adult swallowing each bit first to moisten or crush 

 it ; but from the fourth day on fresh food is given occa- 

 sionally, and from the sixth or seventh day all the food 



