CHAPTER XVII 



Moulting 



A MOST important period in the life of any hawk arrives 

 when she begins to undergo the ordeal of moulting. 

 The annual or biennial change of plumage which occurs 

 naturally in almost all birds affects more or less powerfully 

 their health and condition, robbing them for the time of a 

 certain amount of their strength and vigour, as well as depriv- 

 ing them of a part of the actual mechanical apparatus which 

 serves as their means of locomotion. Thus we have seen that 

 skylarks, when putting on a new set of feathers in August, are 

 very much less able to escape from a hawk than when that 

 process has been completed. To the hawk, whose very sub- 

 sistence depends mainly upon his flying powers, it is obvious 

 that the loss of any big feathers in the wing must be at least a 

 very serious inconvenience, especially if it is combined with a 

 weakening of the whole bodily organism. Nature has not, 

 therefore, allowed the young hawk to mate or breed until 

 after the first moult. At the time when he or she would 

 naturally be busied with family cares — that is, when she is 

 nearly a year old — the minor but still formidable effort of 

 moulting is deemed a sufficient trial. Only when, after 

 assuming the adult plumage, she has kept herself through the 

 whole of a second winter is she called upon to undertake the 

 arduous task of feeding not only herself, but also two or three 

 ravenous and helpless youngsters. The first moult of the young 

 hawk is also arranged to take place at that time of year when 

 it is least difficult for her to find her own living. While the 

 big feathers of her nestling plumage are falling out and being 

 slowly replaced by new ones, the bird world is full of newly- 

 fledged quarry, or at least of quarry which are not yet very 

 strong upon the wing. In other words, the moulting of hawks 

 naturally takes place in summer, just when they are most able 



