POSITIONS ASSUMED BV BIRDS LN FLIGHT. 163 



slow to analyze and follow the different movements, 

 and the only impression the mind receives is one of rapid 

 beating motion, as is so noticeable in the flight of bees 

 and other insects. Too often is this the case when trying 

 to follow the flight of some small bird, the beating of the 

 little wings being quite too rapid for our senses. We will 

 here confine ourselves to those birds possessed of ample 

 expanse of wing, for, generally speaking, the larger the 

 wing the less rapid is the beating, and therefore the more 

 easily can we follow its movements. 



To gain the velocity in order to create the resistance 

 necessary for the support of aU heavier-than-air 

 " machines," some birds run or swim, others simply 

 spring into the air and by the vigour of their flapping 

 achieve the same result ; while others, again, launch 

 themselves from some coign of vantage — a tree or rock — - 

 and in falling gain the desired resistance. In this article 

 I give some particulars regarding the latter method, 

 illustrated by photographs of the Gannet (Sula hassana). 



Stepping to the cliff-edge, and, if there is no cause for 

 undue haste, having raised and partly unfolded its wings, 

 the bird prepares to dive into space. This dive, it should 

 be noted, is not directed downwards, but rather as 

 horizontally outwards from the cliff as may be (sometimes 

 it appears to have even an upward tendency). If the 

 bird is one possessed of broad large wings not much 

 altitude is lost, and it skims through the air in much the 

 same fashion as does a piece of cardboard thrown 

 horizontally. If, however, as in the case of Auks, the 

 wings are small and narrow and the body heavy, then the 

 bird at first drops nearly vertically, only being able to 

 gain a more horizontal course as its velocity increases. 



Sometimes birds of this latter class, presumably through 

 misjudgment of the space they have to work in, do not 

 get the horizontal course in time, and crash into the 

 rocks or sea at the foot of the cliff. This is very noticeable 

 when a group of Puffins {Fratercula arctica) hurriedly 

 takes fiight from a steep boulder-strewn slope. Under 



