MORTALITY AMONG MIGRANT BIRDS 125 



of man. Sudden storms overtake hurrying clouds of 

 migrants, and batter them by the thousands into 

 lakes or seas where they drown miserably, leaving 

 windrows of bodies cast on lonely beaches as mute 

 witnesses of tragedy. Unseasonable cold may attack 

 birds in or near their winter homes and destroy 

 them in countless numbers. Such accidents have 

 beset our eastern bluebird, and on one occasion re- 

 duced its numbers appreciably for a period of years. 

 Cold, with consequent lack of food, has been re- 

 corded as the cause of death of myriads of swallows 

 in the Chaco of Paraguay, where most of the vic- 

 tims were species migrant from south temperate 

 regions, but among them were undoubtedly individ- 

 uals of our own barn swallow. 



W. E. Saunders ^ has recorded a catastrophe that 

 overtook bands of fall migrants passing across Lake 

 Huron in October, 1906. A sudden drop in tempera- 

 ture, followed by a fall of snow ranging from two to 

 eighteen inches according to the locality, apparently 

 caught a heavy rush of migration across the lake. 

 Thousands of birds fell into the water and were 

 drowned, to be cast up subsequently along the 

 beaches, where their bodies in places were said to lie 

 piled one on another. At one point the dead were 

 estimated at 1,000 to the mile, and at another place 

 at 5,000 to the same distance. The bulk of the birds 



^ Auk, 1907, pp. 108-110. 



