306 LIFE-HISTORIES OF BIRDS 



parture in September or October. At- noonday 

 when most other songsters are silent, its song is 

 occasionally heard. The following expresses quite 

 accurately its ordinary ditty: tiviiii. This is 

 uttered sharply and with a gradually increasing 

 intonation. 



The Field Sparrow nests both on the ground 

 and in low bushes. The site of its nest seems to 

 depend upon its environment. In low grounds 

 and in marshes, bushes are usually chosen; whereas 

 in elevated regions, the nest is placed upon the 

 ground in the midst of tall grasses. It is a happy 

 foresight that enables a species to regulate its 

 habits in correspondence with changes in its sur- 

 roundings. Nests which are built upon v the 

 ground, are more loosely arranged than those 

 placed within bushes which are more carefully and 

 neatly constructed. There is a very close resem- 

 blance in some structural parts to the nest of 

 Melospiza melodia, but very little similarity to that 

 of Spizella social is. 



Nidification begins about the middle of May, 

 about four days after mating, and is entered into 

 with considerable diligence by both birds. At least 

 three days are devoted to the labor. Oviposition 

 follows on the ensuing clay, and lasts from four to 

 five days, according to the complement of eggs 

 deposited. Incubation commences on the day 

 following the deposition of the last egg, and con- 

 tinues during a period of 10 days. 



While the female is thus engaged, the male 



