;-304 Transactions. — Zoology. 



followed in season by heavy falls of snow on the suiTOunding 

 hills : but no swarm of rats visited the locality in the suc- 

 ceeding spring : whereas this year, after an unusually niild 

 winter — sufficient snow to whiten our hill-tops not having once 

 fallen — and the crop of fruit on the low lands being very 

 moderate, the rats have made their appearance precisely as 

 they did in 1884. 



The most generalh-received explanation of the periodical 

 appearance of the bush-rats in the northern portions of this 

 island is that they migrate hither from a more southerly dis- 

 trict. Hearing that Kaikoura is supposed to be their place of 

 departure, I made particular inquiries, and find that the animal 

 is unknown there — at least, on the seaward side of the range. 



Putting aside the question from exactly whence these rats 

 come, I will take one of the natural subdivisions of the County 

 of Sounds, and examine what takes place there during the 

 periods of swarming, and how far it coincides with the mi- 

 gratory theory. 



The curiously irregular block of land that divides the 

 waters of the Pelorus and Queen Charlotte Sounds, and in 

 which Mount Stokes forms a prominent feature, contains nu- 

 merous small valle>s or groups of valleys, separated from each 

 other bv rugged wooded ranges rarely less than 1,000ft. in 

 elevation. The only connection this district has with the 

 mainland is the long, narrow mountain-ridge that forms the 

 southern shores of the Kenepuru Eeach. Where the public 

 road crosses this ridge, from the head of Torea Bay, in Queen 

 Charlotte Sound, to Portage Bay, in Kenepuru, is a low 

 saddle about 400ft. high, the distance between the two 

 waters being oidy about 40 chains. The land here is mostly 

 in grass, and is occupied by a settler's family. During the 

 spring of 1884, while the bush-rats were so numerous in 

 Picton, and in the Pelorus, Kaituna, and other inland valleys, 

 they were equally numerous in the valleys round Mount 

 Stokes before mentioned. Now, supposing the migi'atory 

 theory to be correct, the whole of the vast throng of animals 

 must "have found their way thither over the narrow neck of 

 land between Portage and Torea Bays, must have crossed 

 the public road, and nuist have passed the homes of the 

 l)eople there settled; but no such movement was b>- any one 

 observed. Indeed, one fact which I carefully verified this 

 spring seems to me irreconcilable with the migratory theory. 

 It is the simultaneous appearance of the rats in this isolated 

 portion of the Count>- of Sounds and in certain inland valle\s 

 to the south. 



Early last August, noticing that the rats were coming 

 about the low land on the north bank of the Pelorus River, 

 and having occasion at the time to visit Kenepuru, I made 



