WOOD THRUSH 105 



area as his song perch. This form of courtship was observed even 

 after the nest was built. Dr. A. A. Allen (1934) states that he believes 

 the act of copulation normally takes place on the ground. On one 

 occasion I observed what appeared to be copulation but it took place 

 in flight. The birds made several circular flights after which one went 

 to a small trickling stream for a drink. Then the two met in the air. 

 With a flutter of wings and with wings spread, the male lowered him- 

 self to contact the female. This took place about 8 feet above the 

 groimd, just over the top of a bushy shrub. They continued to fly 

 around after each other. 



Nesting. — The nest of the wood thrush is much like that of the robin. 

 Both contain a middle layer of mud or plant material mixed with mud. 

 The wood thrush's nest can be distinguished from the robin's by the 

 presence of dead leaves and sometimes moss. Each wood thrush nest 

 I examined was lined with brown rootlets, whereas the robin's nests 

 were lined with dried grass. 



All except two of 20 nests examined contained paper, cellophane, 

 white cloth, or some white material. One of the two exceptions had 

 long pieces of dried grass hanging from the bottom, yet this was in a 

 position within easy access of paper. The other was away from 

 habitations where such materials were not available. These pieces 

 of paper or rags used in the foundation of the nest would seem to 

 make it more conspicuous. Dr. A. A. Allen (1934) suggests that 

 perhaps enemies do not recognize such large affairs as nests. My 

 interpretation is that its use follows the theory of concealing coloration 

 in that it breaks the nest contour. The bird's white underparts were 

 sometimes used also. The female fluffed her flank feathers so much 

 that they and the under tail coverts were visible, thus breaking the 

 contour lines of the bird. Also, the incubating bird, in holding her 

 head high, shows the white triangle of the chin and throat. It was 

 also noted that when something happened to frighten the incubating 

 bird, she pressed her body more deeply into the nest and held her 

 head back farther, pointing her bill upward. This made the white 

 throat still more conspicuous. 



In all cases where rags, cellophane, and paper were used they were 

 white or transparent. In two instances in which it was known that 

 nests had been broken up or new ones were started, pieces of colored 

 paper, cellophane, and tinfoil were scattered about to see if these 

 would be used. In one case the second nest was already built; in the 

 other the birds moved beyond the area of the scattered materials so 

 the experiment came to naught. White paper was used in both these 

 second nests. 



The nest is a firm, compact cup of grasses and weed stalks with a 

 middle layer of mud or leaf mold. In a few cases where the nest was 



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