IO JOURNAL OF SCIENCE. 



chattering and noise, evidently on the lookout for the enemy, and con- 

 gratulating themselves upon having secured a victory. I have heard of 

 sparrows attacking and driving away pigeons and other birds, but do not 

 remember any record of their daring to attack a hawk. In this part of 

 the Colony the breeding season of the sparrow begins in spring, and 

 ends late in the autumn. The first broods appear in September, and 

 the last in April. I have examined a great many nests, but never 

 found less than five eggs under a sitting bird, more often six, and 

 frequently seven. These are usually all laid in one week. Incubation 

 occupies thirteen days. The young are fed in the nest for eight or nine 

 days. They then return to the nest for two or three nights, after which 

 they have to feed and lodge themselves, sometimes assisted by the male 

 bird. In five instances fresh eggs were found in the nest, along with 

 partly-fledged young. Both parent birds work in feeding the young till 

 they leave the nest, and at first 1 was much j^uzzled to account for the 

 fact that the second laying of eggs was not spoiled during the absence 

 of the mother. From my observation I am convinced that the chief 

 portion of the work of incubation, that is, after the first brood is 

 hatched, is thrown on the young birds; for it must be apparent that the 

 heat arising from the crowding of five or six young birds into a nest 

 would be sufficient to cause incubation. So that by the time the young 

 birds are finally turned out, the earlier laid of the next batch are within 

 a few days of issuing from the shells. Therefore the mother is confined 

 to the nest for little more than half the time to hatch the first brood of 

 the season. Then after a very few days the process is again repeated. 

 This does not occur in every nest, but it is a very important item to be 

 noted when considering the "rate of increase." Moi - eover, in one 

 instance, at least, the young birds belonging to the first brood, raised in 

 September, were themselves breeding at the end of March. I can speak 

 positively, as in the hope of proving whether the birds of one brood 

 mated among themselves, I fastened a bit of red stuff round the leg of 

 each. The only one I saw after they were turned out by their parents 

 was a hen, which had mated with a male from another brood, built a 

 nest close to her old home, and actually reared a brood of her own at 

 the same time as her mother was closing her arduous duties for the 

 season. From two nests I was able to prove that seven broods issued 

 the year before last, but for the purposes of the calculation I am about 

 to make, we will take it that the average is five broods of six each. 

 This is below the mark. "We then allow one-third of the annual 

 increase for deaths. . Here are the results ": — 



Mr. Kirk then read his calculations, of which the following is a 

 summary. Starting with one pah - , Ave shall have — 



At end of First Year (allowing for deaths one-third) 1 1 pairs. 



„ „ Second „ „ „ „ 121 „ 



„ „ Third „ „ „ ., 1,331 „ 



„ „ Fourth ., „ ,, „ 14,641 „ 



„ „ Fifth „ „ „ „ ,,146,051 „ 



He concluded as follows : — 



"This does not take into account those early broods which are them- 

 selves breeding ; nor does it allow more than five broods a year, while 



