Development and Care of the Young 169 



numbers, subject to variations, some of which have been already 

 noticed (Chapter I.). 



The Chipping Sparrow mentioned in the last chapter laid 

 three eggs on successive days, very punctually at about half- 



Fig. 102. Great Herring Gull turning eggs with bill, on entering her 

 nest. 



past four o'clock in the morning. The molding movements 

 and habit of sitting for a few minutes in the nest were con- 

 tinued until close upon the time when the first egg was laid on 

 the 27th of June. At 4.40 A.M., June 28th, the female was on 

 the nest and came off at 4.49 A.M., leaving two warm eggs. In- 

 cubation began early in the afternoon of the second day. So 

 strong had the instinct already become that the bird even clung 

 to her eggs when I climbed into her tree and shook the limb 

 which held the nest. On the third day, June 29th, the Sparrow 

 left her nest, now containing three eggs, at 4.56 A.M. At three 

 o'clock in the afternoon the sitter was absent, but three quarters 

 of an hour later, when it was raining, the Sparrow returned. 



