STUDY OF BIRD BEHAVIOUR 599 



Experimental observation is most easily carried out with domestic or captive animals, and does 

 not here concern us. For a good account of its methods, with many examples, the reader is 

 referred to Washburn's Animal Mini/, already quoted. 



There are two ways of using the following guide : either to take one section or sub- 

 section of it and use it as a basis of observation upon a large number of species; or to confine 

 observation to a few species, and extend the scope of the inquiry to several or all sections. In 

 either case, it will prove helpful and save waste of time if the foregoing pages of the British 

 Hi i-il Book are consulted in order to find what is already known on the subject chosen, and in 

 what special directions new inquiries should be directed. The Index will make this preliminary 

 labour a matter of no great difficulty. 



Under each of the following heads one or more works will be quoted, which will provide 

 an introduction to the subject. 



1. GENERAL CLASSES OF BEHAVIOUR 



The general question as to whether any particular form of behaviour is instinctive, 

 intelligent, or rational is placed here to avoid its repetition under each of the following heads. 

 The test of an instinctive act is that it is performed for the first time without having to be 

 learnt. The test of intelligent behaviour is that it is the product of experience, whether this 

 be direct or imitative. One example will illustrate both instinctive and intelligent behaviour. 

 A chick, taken from its mother, therefore without opportunity of imitating, will peck for the 

 first time at any small object within reach. The act of pecking is clearly instinctive. These 

 first instinctive pecks are not perfect ; the bird's beak may indeed miss the object, but its aim 

 improves with practice. The improvement is the product of experience, and therefore falls, 

 according to the definition, under the head of intelligent behaviour. The criterion of rational 

 behaviour is the capacity to form a mental image, but here the difficulty is to find any 

 satisfactory way of discovering whether on a given occasion a mental image is formed. In 

 dealing with this part of the subject, the utmost caution in interpreting the animal's behaviour 

 is necessary. See works quoted on p. 598 ; and for the physiology of nervous structure see 

 W. M'Dougall, Physiological Psychology. (Temple Primers. Dent.) 



Imitation. In recording all cases of imitation, it is important to note that an act done in 

 imitation of another may be instinctive or intelligent. For example, a young bird utters for 

 the first time in its life a note on hearing another young bird of the same species do so. The 

 first bird may be said to imitate in that it follows the example of the second, but it is not learn- 

 ing by imitation, for the ability to utter the note is instinctive in the species. The utter- 

 ance of the second chick simply provides the stimulus that evokes an instinctive response from 

 the first. But if a bird imitates the note of another species, it has learnt to do something it 

 could not do before, which is the product of its experience, and is, therefore, intelligent. 

 Literature : Lloyd Morgan, Animal Behaviour, chap. v. 1 ; Washburn, Animal Mind, p. 237. 

 See also below, 3, 2, " Song and Notes." 



2. GENERAL ORIGINS 



It would be useless to attempt in a few words to explain the difficulties involved in any 

 question of the origin of instinctive and other behaviour. For an adequate statement the 

 reader is referred to Professor Lloyd Morgan's Animal Behaviour. See also, for general allied 

 questions, R. H. Lock, Recent Advances in the Study of Variation, Heredity, and Evolution, 

 3rd or later edition (Murray); and J. A. Thomson, Heredity, 2nd or later edition. 



