RECONSIDERATIONS 373 



redpole. The trek of the sparrow through the very heart of the 

 North Island is second to none in interest, but he followed the track 

 of man the king's highway. 



Speaking in general, after a time the overpowering impulse to move 

 onwards on a certain line, never to cease to follow a leader, begins to 

 wane. The migratory fever dies down ; a check occurs in the march 

 forward, a check sometimes permanent, sometimes temporary. In 

 either case every link in the long chain of migration is at once affected. 

 The check may be compared in its action to the stopping of the engine 

 of a train, when each carriage is in turn affected, or perhaps better, to 

 the damming back of a stream. The sluice is closed, the stoppage of 

 the head-waters stills the draw of the current behind until at last all 

 seems quiescent, or to continue the metaphor until the dam breaks, 

 giving way at last to irresistible pressure, until in one burst the waters 

 once again rush forward. 



The rabbit, for example, after only three or four seasons, began to 

 settle on its tracks, its earnestness of endeavour to get forward became 

 less keen. Its vanguard had reached the deep swift-flowing Mohaka. 

 The presence of that barrier had been communicated backwards along 

 the whole line, not in any occult mysterious fashion, but, I imagine, 

 simply by a cessation of forward movement by the leading rabbits, by 

 the leading files of rabbit their halt reacting on the second file, that 

 of the second on the third, and so on through the miles-long chain. It 

 is for this reason that there is no huge immediate piling-up of rabbits 

 against a newly-erected rabbit fence the news of a check is automatic- 

 ally passed backwards along the line. There seem to be three phases in 

 a migratory movement the first, that of follow my leader, old and young 

 alike moving onwards in a definite direction ; the second period begins 

 after the van has sustained a check, when the individual links of the 

 living chain begin to breed circlewise, when they begin to stock the 

 country in breadth as well as in length ; the third, of which I have seen 

 one notable example, is the bursting of the containing barrier and the 

 sweeping bare of the breed from grounds previously overcrowded and 

 overstocked. 1 



1 At Peel Forest, South Canterbury, where in the early 'eighties I was cadeting, I waa 

 witness to what I have described as the third phase in a migratory movement. At the date 

 mentioned hares swarmed about the westermost end of Peel Forest run. There were hundreds, 

 there were thousands of them. During the breeding season I have counted seventeen and 

 eighteen running amorously together. They were migrating westwards, and had reached a 



