2 THE ECOLOGY OF ANIMALS 



spend much of their Hves in the woods and fields, and 

 have become famihar with the habits of wild game 

 and birds and fishes. More highly educated people 

 also have for the last two hundred years taken an 

 increasing mterest and pleasure in wild life. They 

 study it for its beauty, or to make collections, or 

 because of the fascination of its complexity. Natural 

 history of this sort has a long and often brilliant 

 record and has created a widespread organization of 

 societies and clubs, with correspondingly large 

 numbers of publications. 



Ecology represents partly the application of scien- 

 tific method in natural history, and partly something 

 more. All the knowledge that has been referred to 

 above is folk-lore or practical knowledge or natural 

 history. When the species of animals are properly 

 identified by an agreed system of names, specimens 

 stored in museums for reference, the habitats of the 

 animals accurately described, the information tested 

 by various different workers, ingenious experiments 

 devised to find out causes, then we can say that 

 natural history has begun to be animal ecology. 

 Ecology means the relation of animals and plants to 

 their surroundings. As a science it may be said to 

 depend on three methods of approach : field obser- 

 vations, adequate systematic technique for determin- 

 ing the names of the animals, and experimental work 

 both in the field and in the laboratory. Or we may 

 consider the points of contact that animal ecology 

 makes with other subjects : animal behaviour leading 

 to comparative psychology, the action of physical 

 limiting factors requiring a knowledge of physiology, 

 the description of habitats with its reliance on 

 physical and chemical techniques, and on vegetation 

 studies, and so on. But when all this has been said 

 there remains a growing body of principles which 

 concern the more purely biological aspects of animal 

 life : the inter-relations of animals, numbers, social 

 organization, migration, food, and many others. 



