THE POWER OF BIRDS TO ENDURE COLD 9 



daily over the snow in pursuit of bluebottles. All 

 these birds must have perished in the end. 



ii 



The fortitude of birds in resisting cold so long as 



they do not run short of food is very 



The power 



remarkable. On one of the early days of Birds to 



endure cold 



of what afterwards proved to be the 



memorable frost of 1895, I watched some wildfowl 

 on a half-frozen lake in Scotland. It was a day to 

 congeal human marrow ; it was freezing hard under 

 an iron sky, and a blinding blizzard flew before a 

 roaring south-easter. There were several hundreds 

 of mallard, widgeon, and teal, with pochards and 

 tufted ducks, and there was shelter for all in the 

 bay behind a wooded island. A few of them took 

 advantage of it, but rather by chance than by 

 choice, it seemed, for by far the larger number of 

 them sat outside for hours on the ice, in the teeth of 

 the piercing blast. Most of them remained motion- 

 less, asleep, with breasts to the wind, and head 

 tucked, not under the wing (a bird never sleeps with 

 its head under its wing), but among the soft scapular 

 feathers above the wing. How is circulation main- 

 tained in their feet? What is the structure of a 



