WOOD THRUSH 109 



pillar, then sang his full song. This was four hours before the hatch- 

 ing of the first egg. 



It took six minutes for the first egg to hatch. Four minutes later 

 the young was free from the shell and it called and opened its mouth. 

 The female fed it with a small insect she had picked up in the nest. 

 She waited 15 minutes after the hatching before she carried away the 

 shell. After leaving the blind, I found the shell about 50 feet southeast 

 of the nest. She took the small end first, then six minutes later carried 

 away the other piece. After she had disposed of the first piece, the 

 male brought food. The female tried to give the food to the young 

 but gave up and ate it herself. Later the male came again with food. 

 The female took it from him and swallowed it. 



The time required for the hatching of an egg varied greatly. In one 

 case it required 22 hours after the shell was pipped. Another egg in 

 the same nest required only 5}i hours. In another instance the shell 

 was pipped one-half inch at 8 p. m., but the egg did not hatch until 

 4:25 the next morning. The time probably varies with the vitality of 

 the young bird as well as with the temperature of the egg. 



The actual hatching is not a consistent procedure. The move- 

 ments of the young cause the shells to open differently, so the young 

 must use various means of freeing themselves from the shell. In one 

 case 10 minutes after the shell was completely cut the left wing pro- 

 truded from the opening. In another 10 minutes the right wing and 

 head were free. The feet were freed last. The head of the bird lies 

 in the large end of the egg. The head is bent downward causing the 

 egg tooth to cut the egg at the large end at a distance of about one- 

 fourth the length of the egg. 



The egg tooth is a small whitish dot on the upper mandible near the 

 tip. It is still visible at the time when the young birds are ready to 

 leave the nest. 



No one procedure was followed consistently in disposing of the egg- 

 shell. In one instance the female carried the two halves separately to 

 a distance of 50 feet. Another time she carried away the larger part 

 but ate the smaller part. In one case she ate the broken bits of the 

 shell as it was being opened by the young. 



Progress of a typical wood-thrush nest: 



Building nest, 5 days, May 28 to June 1. 

 Eggs laid, 4 days, June 2 to June 5. 

 Incubation, 13 days, June 3-4 to June 16-18. 

 Hatching, 2 days, June 16 to June 18. 

 Brooding, 12 days, June 16 to June 30. 



The number of young hatched from 43 wood-thrush eggs laid in 

 1937 was 27, or 63 percent. In 1938, of 51 eggs, 33 young were 



