( 184 ) 

 A PRACTICAL STUDY OF BIRD (ECOLOGY. 



BY 



H. G. ALEXANDER. 



CEcoLOGY, or ecology, is defined by Dr. H. F. Gadow 

 as the relation of organisms to their environment. The 

 relation of this science to the study of geographical 

 distribution, from the ornithologist's point of view, 

 was expounded by Mr. S. E. Brock in a recent number 

 of British Birds. It is evident that a study of oecology, 

 properly conducted, would reveal much that is still 

 liidden with regard to the lives of birds. Perhaps, 

 even, it may be said that the modern desire to learn 

 something of the psychology of animals can only be 

 satisfied by a thorough study of oecology. 



Botanists have already done a good deal of research 

 into the cecology of plant-life ; for them the science 

 is less difficult than it is for ornithologists. It is com- 

 paratively easy for a botanist to choose a certain piece 

 of ground (perhaps only an acre or two), note all the 

 plants growing there at each season of the year, observe 

 which are the most abundant, whether they grow in 

 patches or scattered here and there, what aspect they 

 choose — exposed or sheltered from wind or rain, — the 

 exact nature of the soil, the rainfall, and any other 

 circumstance capable of modifying the plant-association. 

 A similar study of birds is obviously much more difficult. 

 Birds do not remain always in the same environment ; 

 this is the great difficulty. Moreover, the number of 

 circumstances to be taken into account is far greater. 

 Plants, it is true, occasionally depend on the presence 

 of insects or birds or animals : everyone knows that 

 nettles are common on a rabbit-warren ; but birds 

 habitually depend for food, nesting-sites, shelter, and 

 other necessities of their life on the presence or absence 

 of plants, and they frequently depend also on the 

 abundance of insects. If, therefore, we wish to learn 

 the oecology of any bird we must take into consideration 



