Vol \ \ X 

 j-.ii:t 



Bbrgtold, .1 Study of the House Finch, 71 



Counting fertile egga and batched young as potential additions 

 to our House Finch population, we find that the mortality is very 

 large with this species, even if estimated only to include the first 



four weeks after the eggs are laid. 



()\er forty percent of the eggs laid were ultimate failure,, the 



largesl factor in the loss being destruction of the eggS and young 

 by the English Sparrow, a condition to be considered shortly. 

 About ten percent loss is caused by late spring storms, climatic 

 conditions lasting hut ;i short lime, \v\. long enough to cause that 

 much loss. There arc a few minor accidents which have been re- 

 corded during this study: thus one nestling perished because it 

 could not be, or was not, freed from the sticky egg shell; another 

 became entangled in the fibrOUS nesting material, and, unable to 

 leave the nest when full grown, was abandoned by the old birds; 

 once a box was blown down and the eggs destroyed by the fall. 

 One young bird, recognized by its brass anklet, was found crushed 

 in t he street the same day it left the m t 



English Sparrow vs. House Finch. 



There remain at leasl one point in the data accumulated during 

 this study of the House Finch, which, while not relating wholly toil 

 is of so much importance in relation to its future that it rightfully 

 must be examined here. The question is, namely, the relation of 

 the House Finch to the English Sparrow. 



Cooke suggested (Birds of Colorado, March, 1897) that this 

 sparrow in its westward march would perhaps "meet, its first 

 real foe" in Colorado in the House Finch. The information gath- 

 ered in this study will shed some light on this question, which must 

 be examined not only concerning the contact of adult forms, but 

 al o with regard to the nesting habits, fertility, etc. The relative 

 length of the nesting and breeding periods is of first importance. 

 In Denver English Sparrows are commonly seen fighting each other 

 for nesting sites in November, December and January, and the 

 earliesl date when this sparrow has been noticed taking up material 

 for a nest, was January X, on which date a pair of English Sparrows 

 was seen breeding; and also by this time of the year completed 

 nests have often been observed. While both House Finch and 



