I04 PRESIDENTIAI, ADDRESS SECTION D. 



previous year. " When an enumeration of birds was suggested,'", 

 says the author, " the project was the subject of much good- 

 natured banter and some criticism from those who declared the 

 scheme utterly visionary," but these animadversions were based 

 upon the misunderstanding of methods to be employed and the 

 objects in view. The average bird population of that part of the 

 North-Eastern United States devoted to agriculture has been 

 determined with sufficient accuracy to furnish data having various 

 practical and scientific applications, and some useful general 

 information has been obtained in reference to the rest of the 

 counti"y. The average in the North-Eastern States is about 800 

 pairs of birds to the square mile. It is not yet possible to estimate 

 the population of each species, except for a few of the com- 

 monest and most widely distributed, such as the English sparrow 

 and the robin, for which the reports are sufficiently numerous to 

 permit an approximate estimate. The most elaborate report 

 received in 1915 was that of the Campus of Cornell University. 

 Its 256 acres were divided into six blocks, and the survey of each 

 was made by a different person, the whole being in charge of 

 Professor Allen. The densest bird poi^ulation was found on a 

 small private estate near Washington, D.C.,with 135 pairs nesting 

 on five acres, and the most varied population in the bird sanctuary 

 and park, known as Woollen's (iarden, near Indianapolis, wuth 62 

 species on 44 acres." I quote this as illustrating the efiforts of 

 the American Government. In that country a great deal of 

 attention is now being given to the study of Animal (Ecology and 

 animal communities. This most important study is necessary if 

 we are to attempt to comprehend the significance of " Balance in 

 Nature." The ruthless destruction of certain types of animals, 

 notably birds, the importation of an exotic pest, have many times 

 demonstrated the existence of such a " balance." This is very 

 patent in the case of insect pests. Our experiences in this country 

 with the Australian wax scale is a case in point. An understanding 

 of this balance necessitates a knowledge of Animal Oncology, the 

 prelude* to which must be a more or less complete census of our 

 species, and their distributions. Other countries have realised this, 

 and South Africa should fall into line. 



But independent of the directly economic aspect, such a 

 survey would enable us to deal more effectively with the origin 

 and distribution of our fauna. Botanists have realised that the 

 .scientific basis from which we must orientate in grappling with 

 the problem of distribution is oecological, and a great amount of 

 research is accomplished already in that direction. The claim is 

 equally strong to the zoologist. There are portions of our fauna 

 — particularly terrestrial invertebrata — which are practically 

 unknown. The same state of affairs exists in regard to the distri- 

 bution of our littoral shallow-water and deep-water marine 

 forms. As we are living to-day in a time when the generalisations 

 in any one science are so markedly overlapping those of other 

 sciences, the necessity for a deeper knowledge of faunal distri- 



