them, they will devise some means for its practical 

 protection. A very conservative estimate places 

 the average daily consumption of insects by this 

 bird at twenty five, hence we have 18,250 insects 

 destroyed by a single pair in one year. 

 Suppose they raise but one brood of seven, which 

 ought to average fifteen insects a day after they 

 are a month old; placing their period at nine 

 months we have a total of ,46,600 insects destroy- 

 ed by one pair and their offspring in a year. 

 From this it can be seen that a few pair of these 

 birds are of great economic value. 

 The Chickadee commences building about May 

 1st., some years as early as April 10th. 

 The period extends till late in the summer, \ fresh 

 sets having been taken July 15th. in Nebraska. 

 The nesting period of these birds in the same lo- 

 cality is very variable, within a radius of a few 

 miles the following variations may be found; 

 nesting commenced, partial clutch, full comple- 

 ment, and advanced incubation. 

 The reason for this is, probably, that some of the 

 birds wintering here also remain during the breed- 

 ing season and start to nest as soon as spring op- 



