82 BIRDS THROUGH AN OPERA-GLASS. 



unsuspecting insect he has been lying in wait for, 

 and before you breathe settles back on the branch 

 with a spasmodic jerk of the tail. 



And now, as he sits looking for another victim, 

 you have a good chance to note, through your 

 glass, the peculiarities of the bill that gave such 

 a resounding " click." Birds' bills are their tools, 

 the oriole's is long and pointed for weaving, 

 the chickadee's short and strong to serve as a 

 pickaxe ; but when the nest does not "call for a 

 tool of its own the bill conforms to the food habits 

 of the bird, as the white man's needs are met 

 by knife and fork, and the Chinaman's by chop- 

 sticks. So the bills of the robin and bluebird, 

 you remember, are long, thin, and slender, well 

 fitted for a worm diet, while the sparrows, who 

 live mostly on seeds, have the short, stout, cone- 

 shaped finch bill. In the same way flycatchers' 

 bills are specially adapted for their use, that of 

 catching the insects upon which they live. At 

 the base there are long stiff bristles, and the upper 

 half of the bill hooks over the lower so securely at 

 the end that when an insect is once entrapped it- 

 has small chance of escape. 



The phoebe is fond of building in a crotch of 

 the piazza, on the beams of old sheds, and under 

 bridges, apparently indifferent to the dust and 

 noise of its position ; but away from the immediate 

 haunts of man it usually nests in caves or rocky 

 ledges, and sometimes takes possession of the up- 



