79 



Lab«ratory of Orni*UI»fly 

 159 Sapsucker \N»a4* R»acl 

 Cornell Univertity 

 Ithaca, New York 1485 i 



Fig. 68. Bluebirds like hirdboxes it the English sparrows are 

 kept away. 



Instantly a dazed expression comes over her. Something 

 is wrong. She looks long and steadily at the dazzling re- 

 flection coming from down in the grass, then peeks around 

 the limb at the sun that is still doing duty in its proper 

 place. The problem proved too great for her or else she 

 lacked the time to studj' over it longer, for she dived down 

 to her nest to see how her little ones were faring. 



A certain twig on a dead limb of the next tree^ was a 



