6 ANIMAL ECOLOGY 



we might mention the work of the American Bureau of 

 Biological Survey (which was first started in order to study 

 problems raised by the introduction of the English sparrow 

 into the United States), and of other institutions in that country, 

 and similar surveys undertaken under the initiative of the late 

 Dr. Annandale in India. It is clearly necessary to have a list 

 of the animals in different habitats before one can proceed to 

 study the more intricate problems of animal communities. 

 We shall return to the question of biological surveys in the 

 chapter on '' Methods." 



2. Various schemes have been proposed for the classifica- 

 tion of animal communities, some very useful and others com- 

 pletely absurd. Since, however, no one adopts the latter, 

 they merely serve as healthy examples of what to avoid, namely, 

 the making of too many definitions and the inventing of a host 

 of unnecessary technical terms. It should always be remem- 

 bered that the professional ecologist has to rely, and always 

 will have to rely, for a great many of his data, upon the obser- 

 vations of men like fishermen, gamekeepers, local naturalists, 

 and, in fact, all manner of people who are not professional 

 scientists at all. The hfe, habits, and distribution of animals 

 are often such difficult things to ascertain and so variable from 

 time to time, that it will always be absolutely essential to use 

 the unique knowledge of men who have been studying animals 

 in one place for a good many years. It is a comparatively 

 simple matter to make a preliminary biological survey and 

 accumulate lists of the animals in different communities. 

 This preliminary work requires, of course, great energy and 

 perseverance, and a skilled acquaintance with the ways of 

 animals ; but it is when one penetrates into the more intimate 

 problems of animal life, and attempts to construct the food- 

 cycles which will be discussed later on, that the immensity of 

 the task begins to appear and the difficulty of obtaining the 

 right class of data is discovered. It is therefore worth em- 

 phasising the vital importance of keeping in touch with all 

 practical men who spend much of their lives among wild 

 animals. To do this effectually it is desirable that ecology 

 should not be made to appear much more abstruse and difficult 



