72 Bbrqtold, I Study of tha Houst Finch. [j"n. 



English Sparrow seem stimulated to mating and nesting by mild 

 warm weather, yet the second species seems much more suscep- 

 tible to this stimulus, and responds much earlier. At the other 

 extreme oi the year parallel conditions obtain: The House Finch 

 has never been seen, by the writer, building a nest or having eggs 

 iu one, after August, \\hilo the English Sparrow habitually con- 

 tinues egg laying and incubation during this month, in September, 

 and fresh eggs of this species have been taken during the third 

 week in October, It would thus appear that the English Sparrow's 

 season of nidification extends throughout almost the entire year. 

 exceeding that of the House Finch by many weeks, h thus is 

 apparent that the English Sparrow gets its young into the hold 

 earlier and during a much longer period than does the House Finch, 

 which, in itself, would almost certainly cause it to win against the 

 House Finch in a struggle between the two species. The male 

 English Sparrow does as much oi the nest building as its mate, while 

 the male House Finch does nothing in this way to help its mate. 

 a difference which may hasten and facilitate the completion oi an 

 English Sparrow's nest in a shorter time than that oi the House 

 Finch. 



'The Sparrow's large bulky nest, wherever situated, with its usual 

 lining of feathers, is far more resistant to snow or rain than is the 

 open Finch nest, another factor tending to promote the multiplica- 

 tion of the English Sparrow, under conditions in which the young 

 House Finches perish. The English Sparrow's greater adapta- 

 bility is also in its favor. This flexibility oi nesting exhibited by the 

 English Sparrow comes into prominence in its habit, in Denver, of 

 using abandoned nests of Bullock's Oriole (/, bullock^ in which to 

 raise its \ oung. 



The loss of nests, eggs and young oi the House Finch through 



direct destruction by the English Sparrow is very large. It was 

 lb" , in some of the nests studied by the writer, and. moreover, 

 this lb 1 J loss of eggs does not include the very large potential loss 

 of House Finch eggs and young brought about by destruction of 

 nests b\ English Sparrows before the House Finch eggs are laid in 

 them. One should remember also that there must be a loss of 

 House Finches greater than 16% through the English Sparrows 

 when they are not prevented from harassing the House Finch. 



