318 LIFE-HISTORIES OF BIRDS 



parent-birds destroy great numbers of noxious 

 caterpillars. 



Its flight is low, firm, and but slightly sustained. 

 Its general movements are the inpersonation of 

 agility. It is mainly terrestrial in habits, and sel- 

 dom attains to any considerable height in its 

 search after food. 



Its ordinary call-note may be quite accurately 

 expressed by hwl repeated at irregular intervals. 

 A simple twlche, the last syllable repeated quite 

 sharply, is expressive of anger; while its cry of 

 vexation and disappointment is indicated by twl- 

 twl-twjo, twi-twl-twoo, iterated in a harsh and dis- 

 agreeable manner. Finally, its song lacks both 

 variety and expression, and is in striking contrast 

 with the songs of Melospiza mzlodia, and Spizella 

 pusilla, and cannot fail to attract attention by its 

 utter inharmoniousness. 



This bird mostly builds in a hollow tree or a 

 box. In walls overgrown with the ivy, scores not 

 only find comfortable shelter during the rigorous 

 winter months, but also suitable accommodations 

 for nesting purposes. Where the above conveni- 

 ences are not available, actuated by a true parental 

 instinct, a couple sometimes nidificate between the 

 forked branches of a maple. A case in point 

 came under our immediate observation during the 

 summer of 1874. 



During favorable seasons nidification ordi- 

 narily commences in the early part of April. 

 The spring of 1875 being an unusually backward 



