316 HOMING WITH THE BIRDS 



not have been built through a subconscious im- 

 pression from her ancestors, since they did no such 

 building. It is going beyond any mentality I 

 have ever attributed to a bird in natural history 

 work, but this nest proves a number of separate 

 mental conceptions on the part of the bird. She 

 had to realize the confinement of her usual struc- 

 ture, which gave her no means of escape in case 

 of attack from above. She had to resent her shut- 

 in condition while brooding, and decide that she 

 would try to remedy it. The nest proves her first 

 trial a failure. She outlined a window and began 

 weaving around it; then realized that it was too 

 high for her to brood and use it at the same time. 

 So she abandoned her first effort and designed and 

 completed her window where she could sit on her 

 eggs, and at the same time, have light, air, and a 

 view from her location. Also, the window was 

 large enough to afford her means of escape in case 

 a squirrel or screech owl attacked her from above. 

 This nest was also stayed at one side so it would 

 hold firmly in a gale. Notice the lashing of cord 

 that runs from the nest to the branch which holds 

 it at this twig, where it is plainly tied in two slip 

 knots, then carried back into the body of the nest. 

 The heavier stay wound several times around the 

 top limb outlines the window and is then carried 

 below and looped around the limb, brought back, 

 and woven into the nest. The entire structure 

 gives evidence of extraordinary skill in construe- 



