236 Tranmctions. 



If the process was continued at the same rate for five more 

 years, and if all the birds lived, the single pair, at the end of 

 ten years, would be represented by 51,874,849,202 sparrows. 

 When figures are placed together in that way, of course, they 

 are absurd. The increase assumed would never be reached, 

 even by rapid breeders like sparrows. I may add that an 

 American ornithologist, on whose system the table has been 

 drawai up, states that it is no unusual thing for a pair in the 

 latitude of New York to rear twenty or thirty young in a year, 

 and, assuming the annual product of a pair to be twenty-four, 

 and that they all lived, he works out the progeny of that pair 

 for ten years at 275,716,983,698. It is only fair to state that 

 he points out that the actual increase must be only a small 

 fraction of that total, which is based on assumptions that are 

 never likely to be realised. His investigations show that it is 

 probable that the large colonies at Galveston (Texas), Salt Lake 

 City, Utah, and San Francisco have resulted wholly, or at any 

 rate to a large extent, from the few pairs originally introduced 

 at those places ; but he finds that it is impossible to apply the 

 same remark to most of the other centres of abundance in the 

 United States. 



The evidence I have been able to gather seems to point to 

 the fact that the five sparrows liberated by Captain Stevens in 

 Lvttelton in 1867 must have been responsible for large numbers 

 of the sparrows that spread over Canterbury in the following 

 vears. If there was only one pair in that little consignment, 

 it must by this time have produced sufficient progeny to stock 

 a large portion of the South Island. 



I have endeavoured to ascertain whether the rates of in- 

 crease are affected by the different ohmatic conditions in this 

 colony, but these birds seem to have such remarkably strong 

 constitutions that they thrive equally well in the cold of Otago 

 and Southland and the warmth of Auckland. All the informa- 

 tion supplied points to the fact that they are more numerous 

 in the southern provinces than in the northern ones, and breed 

 as rapidly in one as in the other. It is true that they are 

 sometimes found dead in large numbers in the severe winters 

 of the south, but this is more Ukely to be attributed to lack of 

 food than to the severity of the climate. Wherever there is 

 close settlement, in fact, sparrows are found in countless num- 

 bers, and in the enjoyment of the very best of health. It is 

 stated that in America they do not increase as rapidly or as 

 steadily in cold climates as in temperate ones, but I certainly 

 carmot say that that is the case in New Zealand. 



It is interesting to note that the first sparrows were taken 

 to the United States in 1850, seventeen years before Captain 



