°j^(, J Australasian Ornothologists" Union. I "jg 



Ryan, of Nhill (Victoria), spent two days in the Mallee fringe, 

 where an interesting lot of birds were observed. The notes 

 obtained will form the subject of a short paper in some future 

 issue.] 



Report on the Birds of Kangaroo Island : a 



Comparison with Mainland Forms. 



Bv A. G. Campbell, Melbourne. 



It is difficult to believe that all forms of life have been evolved 

 by the influence of differing conditions, though it seems obvious 

 that numbers of species have had a common ancestor. In a 

 general way there are influences creeping in which there are now 

 no means of gauging, so far back are their beginnings, but it is 

 most interesting to search out connections between allied forms 

 of the present day. 



One form in one locality is only worthy of being made a 

 species separate and distinct from another form in another 

 locality if its points arc fairly constant. The characters of 

 each must not grade toward and merge into one another, or they 

 must be considered one and the same species. 



Slight differences must be expected if the theory of origin by 

 adaptation to environment holds good. For slight differences 

 will in time become the more marked ones that differentiate 

 species. 



Where geological change has occurred and where a sea or a 

 desert has crept in and divided two parts of a similar area, 

 differences at first sight would become more and more distinct. 

 Ultimately a species on one hand would be found with no 

 connecting links to one on the other. This is still more marked 

 if the break occurs on an east or west line, and if one section be 

 forced to a more southern habitat than the other. 



South-eastern Australia has its own quota of bird life. In 

 Western Australia there are many species the relation of which 

 to forms in the south-east can be distinctly seen. But they in 

 most instances show some constant difference that makes them 

 worthy of another specific name. Midway — that is, in South 

 Australia — there might be expected some intermediate dif- 

 ferences. But as these cannot be traced sufficiently it was with 

 great interest that Kangaroo Island was searched. The results 

 were not disappointing, for many forms distinctly worthy of 

 being termed links between eastern and western species were 

 discovered. This island has been locked up, so to speak, for 

 many years, and was found to contain a good record of condi- 

 tions that on the mainland have long since been interchanged 

 away. It is interesting to record, too, that the affinity of 

 Kangaroo Island birds is with those of Victoria, and not with 

 those of South Australia, as might be expected. 



