318 HOMING WITH THE BIRDS 



of Ohio." Professor Jones found this nest in 

 Iowa, and graciously permits me to reproduce it 

 here. The twin nests would not be so remarkable — 

 female birds often locate in colonies or near each 

 other — had the nests been the work of two females; 



Double vireo nest 



bui Professor Jones asserts that the double struc- 

 ture was built by one pair, that the female divided 

 hereggs between them in laying, while both male and 

 female were brooding when lie found the nest. I 

 can not attribute the work on this structure either 

 to " instinct" or "subconscious mind." It appeals 

 to me as plain knowledge. The birds surely knew 

 thai they were building two nests and why they 

 built them. The hen knew she was laying in two 

 nests and I he male bird that he was brooding when 



