150 BEHAVIOR OF PIGEONS. 



activities. Feeding-grounds and breeding-grounds are illustrations. In the pigeon 

 most of these needs center around the nesting-site and its immediate vicinity. 

 Such animals must be able to react to topographical relations. An instinctive 

 organization will hardly suffice for an animal whose relation to the environment 

 is exceedingly complex and variable. Instincts are adaptations to the relatively 

 fixed and constant aspects of environmental conditions. The ability to learn easily 

 and quickly a complex system of topographical habits would thus be one of the 

 fundamental needs of animal organization. Most animals have the degree and 

 kind of intelligence which their life demands. Many illustrations of this capacity 

 of pigeons are given. The preference for a roosting-site may be established in 

 one night. In "pair D" the preference for a new nesting-site in a box filled with 

 dry dung was fixed with one experience of an hour's duration. A male broke one 

 nesting habit and developed a new one in 5 or 6 trials. The nest is not wholly an 

 object, but partly a position in reference to other objects. Freed birds at first 

 are lost, but they learn to locate the nest in a large yard in a couple of trials. The 

 ability of homers is supposed to consist of this capacity to learn quickly and retain 

 tenaciously a complex system of topographical habits. Viewed from this stand- 

 point, one is almost tempted to assert that pigeons possess as much intelligent 

 capacity as humans for these particular lines of activity. 



(2) Pigeons are also able to acquire rather readily systems of differential 

 reactions to the individuals of the group. Because a bird can acquire a habit of 

 reacting to another bird as an individual, e.g., a mate, it does not follow that as 

 a matter of fact it does acquire a habit for each individual of the group. The 

 differentiation may be between mate and not mate, species and foreigners, member 

 of flock and stranger, etc., but individual reactions are possible. While certain 

 distinctions such as species, sex, and enemy find a basis in instinct, yet instinct 

 does not provide in advance for all possibilities of individual differentiation. While 

 such species differentiation is partly innate, it is to a large extent acquired. 



A novel species reaction was acquired by a young geopelia at the age of 7 

 weeks. Placed with its own kind, a new reaction was acquired in less than 4 days. 

 The selection of a mate is at first a process of discovery; each bird reacts instinc- 

 tively to a certain type of behavior. After the mating is established, however, the 

 members of a pair react to each other on a different basis. They react to each 

 other as individuals and recognize each other at a distance. This new mode of 

 reaction is acquired and easily established. A pair of young brought up with each 

 other will have learned at the age of 4 weeks to respond differently to each other 

 than to others of like age and species. Inside of a large group smaller groups are 

 formed and differential habits established. Attitudes of fear, distrust, and confi- 

 dence toward individual birds are very easily modified with experience. 



(3) Many acts are improved through exercise. The influence of experience is 

 probably influential upon all of the fundamental activities. Illustrations noted in 

 the manuscripts refer to such activities as egg-laying, flying, drinking and eating, 

 and methods of fighting. 



