124 The Wilson Bulletin — No. 84. 



eight in eig'ht days. It was as if a baby that weighed ten 

 pounds at birth increased his weight at the rate of twenty 

 pounds on the second day, eighty pounds on the eighth day, 

 and one hundred and sixty pounds on the sixteenth day. The 

 gain in weight of No. 3 that weighed 46 and 1-2 grains in 

 the beginning was even more remarkable. On the eighth 

 day No. 3 weighed 420 and 1-2 grains. 



Specific notes on the daily progress of the four young 

 Olive-backed Thrushes. 



July 11, the beginning of the first day in the nest. As be- 

 fore stated, on the tenth day of incubation^ at 11 :30 a. m. I 

 foimd two limp young Thrushes lying prostrate in the nest. 

 They had been out of the shell sufficiently long for the dark, 

 burnt-umber, natal down, one-half inch long to dry. The 

 birds, including their beaks, feet, and legs were a tint of burnt- 

 orange. They rested on the belly, had a tendency to curl up 

 in the form of an egg and roll until stopped by the legs and 

 wings. 



The end of the first day. The three oldest birds lay prone 

 in the nest, vibrating as one. One gave the food reaction in 

 the nest, but when removed from the nest, none gave the 

 food reaction. Their beaks, feet and legs were a trifle yel- 

 lower than the rest of the body. 



The end of the second day. The three oldest birds bid not 

 gave the food reaction out of the nest. The natal down on the 

 fourth nestling at 11:55 a. m. was not entirely dry. When 



Length of (all measurements in inches.) 



Body. Bird 1. Bird 2. Bird 3. Bird 4. 



July 11 1 and 11-lG 1 and 11-lG 



July 12 2 1 and 3-4 1 and 11-16 



July 13 2 and 3-lG 2 and 1-8 land 7-8 laud ^MG 



July 14 2 and 9-lG 2 and 11-lG 2 and 1-lG 1 and 13-16 



July 15 2 and 13-16 2 and 14-16 2 and 9-16 2 and 1-32 



July 16 3 and 1-8 3 and 3-16 2 and 11-16 2 and 1-4 



July 17 3 and 1-2 3 and 5-8 3 and 1-8 2 and 11-16 



July 18 3 and 5-16 3 and 5-16 3 and 3-8 2 and 7-8 



.July 10 3 and 3-8 3 and 5-lG 2 and 13-16? 3 and 3-8 



July 20 3 and 3-4 3 and 3-4 3 and 7-16 3 and 3-8 



July 21 4 and 11-16 3 and 5-8 



