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TUTIRA 



well to give a general account of the routes by which these uninvited 

 guests have invaded the run. 



The movements of masses of living things may or may not be blind 

 and involuntary. In any case, it is certain that some roads of expan- 

 sion are favoured over others, and that, in the selection of these, birds 

 and animals follow, like man, the law of the line of least resistance. 

 That line may, in the North Island of New Zealand, be generalised 

 as the line of light. 



There are three natural highways by which imported animals 

 have chiefly travelled from centres of acclimatisation north and south 

 of the run. Each of them is a line of light fringing or piercing the 

 dense vegetation of a fertile, warm, well - watered land. They are 

 the coastal route, the hill-top route, the river-bed route. 



During their journeyings to the run from different centres of 



Line of light coast showing native clearings. 



liberation, many of the migrants especially the bird migrants have 

 at different periods, passing through different districts, used all 

 of these ways. The coastal route on the whole has been most 

 helpful ; upon it certainly the final laps of many species have been 

 accomplished. It has, in the first place, offered superior attractions to 

 any other line of ingress in the matter of warmth. By following the 

 coast - line, which in New Zealand happens, generally speaking, to 

 be also the line of human settlement, Maori or European, migrants 

 have not only procured food more easily, but have, through man's 

 tillage of the ground, found food of a suitable sort. It must be 

 always remembered that the alien vegetation of New Zealand was 

 well established on pioneer plots before the majority of the alien 

 animals and birds had arrived ; that there were procurable the seeds 

 and tender leaves of imported garden plants, grasses, and weeds. 



