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TUTIRA 



rushed through good and bad alike. Without a base, however, he 

 perished from insufficient numbers ; like the seed in the parable, when 

 the sun was up he was scorched, and because he had no root he withered 

 away. I could never trace the movement beyond the southern edge of 

 the Poverty Bay plain. It passed along the east coast like a comet 

 through the heavens, fading away in front and leaving no trace 

 behind. 



The origin of movements seems to be congestion. Where there 

 is no great increase of numbers, as in the case of the pheasant, the 

 quail, the rook, and other species, there is no accentuated move- 

 ment. Spread is almost fortuitous, a merely negative pursuit of the 

 summum bonum of animals food, shelter, and breeding accommoda- 

 tion. On the other hand, species whose rate of increase is great multiply 



about the spot of liberation until 

 the limit of food - supply, clean 

 quarters, and breeding accommoda- 

 tion is reached. The normal spread, 

 perhaps, of a species is circlewise 

 from a centre, perhaps also it would 

 continue with equal speed in all 

 directions for all time were exactly 

 similar environments anywhere to 

 be discovered. Sooner or later, 

 however, weather conditions, physi- 

 cal and geographical barriers, limit such circular extension. Where a 

 barrier is touched in any one quarter, pressure of growth is trans- 

 ferred to other segments of the circle, its original shape is lost. 

 At last, where resistance is least great, the living contents break forth. 

 It may be that disinclination to move persists for a considerable period 

 after the limits of comfort have been reached. There is a dread of new 

 conditions, greater or less according to the nature of the breed, which 

 prevents many species from severing widely the bond of one another's 

 company. They prefer discomfort to disintegration ; leadership is un- 

 coveted it is a post of danger and dread, the desire of each 

 is not to lead. As all, however, cannot be followers, the position of 

 danger is distributed over a large number of individuals. A 

 flock of sheep, not yet listless with dogging or careless on a well- 

 known road, travels with a head formation rather blunt than broad, 



Mob of travelling sheep. 



