28 THE ENGLISH SPARROW IN AMERICA. 



fed in the nest for about a week, and then. for several days (sometimes 

 as many as ten) after leaving it. More eggs may be laid in the same 

 nest as soon as the young leave it, and in this way it is possible for a 

 pair of Sparrows to rear one brood each month for five or six months, 

 but it seems probable that generally the broods do not follow each 

 otber quite so rapidly. 



It has been claimed that Sparrows which are hatched in the early 

 spring often pair and rear young during the ensuing summer or autumn, 

 but although several of our correspondents state this to be the case, 

 we have not received sufficient evidence to justify us in supporting 

 these views. Another theory which would account in part for the rapid 

 increase of Sparrows is advanced in the following communications: 



Dr. W. H. Bergtold, of Buffalo, N. Y., writes: 



As regards the number of broods and young reared by a pair of Sparrows in a year, 

 I wish to make a statement and put forth a theory that I have never seen advanced 

 before. I have repeatedly examined nests of this bird containing nearly full-fledged 

 young, two or three young in more or less advanced stages of development, and sev- 

 eral eggs of various degrees of incubation, some being nearly fresh, while others were 

 about to bi\ ak through. I gather from these facts that the Sparrow, at least in some 

 cases, lays and continues to lay a succession of eggs so long as the weather is not too 

 cold; and as the young attain a sufficient amount of strength they are expelled from 

 the nest. Assuming such to be the case we can easily see how much of the incuba- 

 tion work is taken from the parents and thrown on the young, who, by their bodily 

 heat and proximity, readily take up such duties (quite unintentionally, I imagine), 

 and also how much work cau be given to the proper maintenance of a generous food 

 supply for both the old and young. 



This constant stream of outpouring Sparrows accounts for the rapid manner in 

 which this species multiplies. (August 21, 1886.) 



J. B. Stockton, of Toronto, Kans., writes: 



The Sparrow had a nest under the eaves, and all summer there seemed to be fresh or 

 newly-hatched birds in the nest. There were eggs in the nest all the time, and the 

 warmth of the unfledged young hatched the eggs, so that there was a continuous and 

 uninterrupted stream of full-fledged birds coming from that same nest all the season, 

 and unfledged ones of various degrees at the same time remaining in the nest. I have 

 never kuown or noticed anything of the kind with any otber bird. (October 6, 1886. ) 



Although such cases as the foregoing may occur with more or less 

 frequency, they certainly are not the rule, as it is certain that in most 

 cases all the eggs are laid before any are hatched, and all the young 

 leave the nest at about the same time. 



Moreover, itisnot necessary to resort to such a theory to account fortho 

 rapidity with which the Sparrow increases. It is a hardy, prolific, and 

 aggressive bird, possessed of much intelligence and more than ordinary 

 cunning. It is domestic and gregarious in habit and takes advantage 

 ol the protection afforded by proximity to mau, thus escaping nearly 

 all the enemies which check the increase of our native birds. Moreover, 

 for many years it was looked upon with favor, and both food and shelter 

 were provided for it. 



Its fecundity is amazing, and from the testimony submitted itis evident 

 that it is no unusual thing for a single pair, in the latitude of New York, 



