Nest Life of the Catbird 169 



Incubation. 



No data on incubation was secured in either of the first 

 two studies and nothing" very definite as to the length of the 

 period in the last one. Nest C was found on July 9 and the 

 first egg hatched on the twenty-first while the last one did 

 not hatch until the morning" of the twenty-second. This would 

 make the incubation period at least twelve or thirteen days. 

 The position the female assumed while incubating was char- 

 acteristic. She came on the nest facing the blind and settled 

 into it by a series of motions from side to side, working the 

 feathers of the breast and belly well around the eggs. When 

 she was down in the nest her tail stood almost perpendicular 

 to the body and the head was well thrown back. 



Hatching. 



Mr. Smith watched the hatching of one of the eggs in 

 nest B while two out of three in nest C hatched during the 

 time the nest was under observation. The first egg in nest 

 B hatched before the study began but the second was ob- 

 served to hatch on the morning of July 3. The other two 

 eggs never opened as the nest was deserted on this same 

 day. Mr. Smith says concerning the hatching of the second 

 egg: "At 4:55 a. m. one more egg was pipped, evidently by 

 the old bird, as it was chipped inward and directly around 

 the center of the egg. This egg hatched at 5 :55 a. m., the 

 young bird forcing the shell open by rolling and plunging 

 gently and by some use of the feet and wings. At 6 :45 the 

 female carried away half of the shell and returned at 6 :48 

 with something in the bill which she swallowed, tho I could 

 not determine whether it was the crushed shell or food. She 

 left the nest at 6 :53 only to return at 6 :55 and take away 

 the remaining shell." 



in nest C the first egg was pipped at 9 :00 a. m. on July 20 

 and at 7:00 p. m. all three were pipped in practically the 

 same place. The first break in each shell came from within 

 and was a little beyond the center of the egg toward the 

 larger end. It was simply a slight bulging evidently pro- 



