THE NATURAL ENEMIES OF BIRDS 133 



exterminated, Mr. Forbush estimating that it had 

 been reduced at least ninety-five per cent. 



During the winter of 1911-12, which was excep- 

 tionally severe, many reports received from por- 

 tions of the northeastern United States indicated 

 that many birds perished. The sleet and snow cov- 

 ered their food so that the birds fell easy victims 

 to the low temperatures. Water-fowl perished by 

 the thousands on the Delaware River. In Iowa it 

 was estimated that seventy-five per cent of the 

 bob-whites and prairie chickens perished. In New 

 Jersey it was reported that grouse and quail were 

 dying from hunger on account of a coating of ice 

 beneath the snow, through which the birds could 

 not dig holes for food. Similar reports came from 

 Kansas. The marshes and coves by the sea, where 

 water-birds usually stay, froze so that the birds 

 were not able to secure food. 



In the late winter of 1895, bluebirds were over- 

 taken by a spell of cold weather hi the South, as a 

 result of which thousands perished. The diminished 

 number of bluebirds was very noticeable for many 

 years afterward. 



Mortality during spring. Dr. T. S. Roberts re- 

 ports in " The Auk " a Lapland longspur tragedy 

 that occurred in southern Minnesota and northern 

 Iowa in March, 1904. Apparently a great host of 

 these birds were migrating to their northern home 

 on the night in question, when they were over- 



