150 TiJi: W'ji SON IUllktix, Xo. 72-73. 



This record shows that the increase in the average weights 

 is upward of one hundred grains per day for the first eleven or 

 twelve days, after that from twenty-five to forty grains daily. 

 All my records show that there is a period of four or five days 

 somewhere hetween the thirteenth and twenty-second day 

 when there is little increase, or sometimes a decrease in weights 

 for a few days. Several other species, whose growth by 

 weight has been studied, have furnished similar examples, and 

 as this period of very slight increase, or possibly decrease in 

 weight occurs not far from the time the nestlings begin to show- 

 fear, and their wing-feathers burst from enclosing sheaths, it 

 is probable that three points of interest center about this period 

 of their lives. 



Although Flickers remain in the nest much longer than luany 

 of our common birds, and their rate of growth is very fast at 

 first, yet the scales show that this growth is not proportionately 

 very much greater than that of some other birds. Taking the 

 following species on the ninth day of their lives we may find 

 that the Flicker weighs twelve times as much as it did when 

 hatched. Phoebe and Red-winged Blackbird have each in- 

 creased their weight ten times, the Song Sparrow and Catbird 

 eight times, while the Mourning Dove weighs but seven and a 

 half times its first weight. 



Numerous attempts have been made to ascertain the amount 

 of food brought to the nest for one meal. The young were all 

 removed from the nest except one hungry fellow that was 

 weighed just before and after the visit of the parent. The in- 

 crease in weight must have been that of the dinner just deliver- 

 ed. Experiments show that to a nestling weighing 7 4;i grains 

 was given a breakfast that weighed 70 grains, to one weighing 

 1430 grains a dinner of 118 grains, and to another that tipped 

 the scales at 1530 grains a supper of 103 grains. Proba])ly the 

 wei<7ht of the averac^e load is not far from one hundred grains. 



The numher of daily visits increases with the age of the 

 nestling from about ten on the first day to four or five times 

 that nuiuber later. Six or seven meals niav be served within an 



