° 1918 J Perry, Vesper Sparrow and Hermit Thrush. 315 



tail. They were able from the first to raise their large heads on 

 their long, wobbly necks, and open their mouths for food. In fact, 

 they seemed able to do this before the down had scarcely dried. 

 They soon became rather active, ill-mannered, aggressive nestlings, 

 squabbling over their food. Their bodies began to be marked with 

 distinct feather tracts. On the third day the wing pins had broken 

 through the skin. Their eyes began to open about this time, and 

 they could make a faint call. This became a loud "zee, zee" by 

 the sixth day. They no longer remained quietly huddled in the 

 bottom of the nest, but began to assume a definite position, with 

 their heads resting on the rims of the nest, their breasts against 

 the sides, and their claws firmly clasped in the lining. When they 

 raised their heads and opened their mouths, they looked like a 

 bowl of queer flowers. Now and then they stood up and flapped 

 their wings. When they were six days old, they began to preen 

 their bursting feathers. This they did by seizing each feather at 

 the base, and drawing the mandibles over it toward the apex. 

 This helped to remove the dried sheath. 



In order to estimate the rapidity of their growth, I weighed 

 them every day. Since they soon became too active to keep on 

 the scale pan, I made a cheese cloth bag to put them in while I 

 weighed them. To distinguish one from another, I marked them 

 with paint on different parts of the body. Having the birds 

 marked also gave me an opportunity of determining if the parents 

 fed them impartially. I decided that they fed indiscriminately. 

 The nestling stretching out its neck the longest, received the most 

 food. In spite of this, however, the following table shows an 

 approximately equal increase in the weight of each of the three. 



Table I. 



SHOWING WEIGHT IN GRAMS OF NESTLINGS FROM DAY TO DAY. 

 Date July 19 July 20 July 21 July 22 



Clear Cloudy Cloudy Cool 



