THE HEIGHT AND SPEED OF FLIGHT 51 



The bird rose and soared in ever-widening circles 

 until it was a mere speck, even when seen through 

 powerful prismatic glasses ; the great stretch of its 

 wings alone enabled me to watch it for so long. 

 When at a great height I will not guess what 

 elevation it ceased its circling flight and made 

 straight for the north. 



In October I saw several flocks of redwings leave 

 the Spurn. The}' rose to a great height before 

 directing their flight southwards, although the 

 Lincolnshire coast was plainly visible. 



Great differences of opinion have been expressed 

 about the speed of migrating birds, and here again 

 Gatke's estimates, on account of the weakness of 

 his arguments and his immense presumption, cannot 

 be seriously considered. There are but few measured 

 speeds, and most of these, except perhaps the ducks 

 and geese referred to already, are of birds travelling 

 at low elevations. 



Many birds, especially day-migrating swallows, 

 hooded crows and other birds, frequently travel at 

 slight elevations ; it is not unusual to see birds at 

 sea flying a few feet only above the waves. Mr W. 

 Eagle Clarke, whose systematic observations de- 

 mand the profoundest respect, again and again urges 

 that the direction of the wind has little effect upon 

 migration, but that the force of the wind may make 

 migration impossible. At the Eddystone, where he 



