CHAPTER VI. 



WHERE BIRDS SLEEP. 



... I 



TTTHEN I was a boy, nothing connected with 

 ^ * the life of birds puzzled me so greatly as the 

 question of where they slept. I often tried to watch 

 them to roost, but with little success. That birds 

 sleep very lightly, and are easily awakened, is a 

 fact I have proved over and over again by casting 

 a small pebble in the air in such a way that it 

 would fall vertically into a large evergreen where I 

 knew a number of House Sparrows were roosting. 

 Although the stone made very little more noise in 

 its descent through the leaves than a big rain-drop 

 would have done, it instantly sent several birds out 

 in a great flutter of alarm. I have also noticed 

 how exceedingly difficult it is to approach Golden 

 or Green Plovers at night-time, especially on peaty 

 soil, which easily transmits the slightest vibrations, 

 and thus, I am persuaded, assists to a very con- 

 siderable extent in awakening sleeping birds. 



To many people it is a profound puzzle how a 

 slumbering bird retains its balance on a slender 

 twig or branch that is liable to be swayed more or 

 less violently to and fro by a strong breeze. The 

 answer is very simple. Birds only roost on such 

 branches as they can grip firmly with their toes 

 and claws, and in sitting down upon them the 

 bending of the knee joints so contracts the muscles 



