xx Introduction 



whose young left their nest the moment it was disturbed. The 

 branch which held this nest was thereupon sawn off, and 

 mounted in a convenient spot beside a barn which happened to 

 be near, one of the young being used as a lure. While this nest 

 was being moved, I placed the fledgling under an old-fashioned 

 wire screen used to cover food, when the mother, true to her 

 parental instinct, came promptly with an insect and alighted on 

 the wire net. Some photographs were later made, but, although 

 in this case parental instinct was the force employed, the dis- 

 placement of the nest had no significance. 



The first experiment in moving the nest, branch and all, was 

 made upon Cedar Waxwings, August 3, 1899. Two days later 

 the tent was pitched before their nest, and in a few minutes I 

 had the pleasure of seeing both birds approach and feed their 

 young with choke-cherries by regurgitation, as if nothing had 

 happened. The scenes were as fascinating as they were novel, 

 and a number of photographs were made from the tent, one of 

 which is reproduced on page 89 of this work. It thus became 

 evident that an important principle was involved, and that the 

 key to the problem of approaching the wild bird had been found. 

 Every subsequent experiment tended to confirm this conclusion. 



The method is based on the solid ground of animal instinct, 

 is capable of many refinements, and in judicious hands will add 

 wonderfully to our knowledge of birds during that most interest- 

 ing of all periods life in the home. 



IV 



With the opportunities of closest approach which this method 

 affords, it has been possible to give an exact analysis of nest 

 life. Attention will be called to the chain-like relation of the 

 different serial acts performed at the nests, such as the capture 

 and delivery of the prey, the inspection and cleaning of the nest, 

 and brooding and spreading over the young. We have found 

 the same type of behavior recurring with striking regularity in 

 those orders of birds already studied, which feed their young 

 for a considerable period, but the field is wide and unexplored 



