BIRDS OF PREY 19 



buzzard and peregrine, divide up the land between them- 

 selves with definite beats of considerable extent, and object 

 to trespassers of their own species or any other that by the 

 rules of the wild they consider their inferiors. Probably the 

 surviving species are still as thickly distributed in some of 

 the wilder mountain and sea-coast districts as they were 

 many centuries ago. But although birds resent trespassers 

 of their own species on their special territory at the breeding 

 season, the prohibition does not extend in many cases to 

 pairs of other kinds. Partly this tolerance may be due to 

 the absence in such instances of conjugal jealousy. But it is 

 largely due to the fact that birds of different species prefer 

 different prey, even when they are of the same general 

 habit ; and thus there is room for a pair of buzzards and a 

 pair of sparrow-hawks and a pair of kestrels on the same 

 stretch of moorland and wooded dingles, though any single 

 pair of the three species would require the whole or almost 

 the whole territory for itself, if its rivals were of its own 

 kind. 



There was probably never a time when the sky over a 

 Scotch deer forest or English woodland in summer was 

 thickly peopled with eagles, hawks, and buzzards, as is 

 sometimes represented in fanciful pictures of the past. The 

 only occasion when birds of prey periodically appear in 

 anything that can be called a flock is at the migration 

 seasons in spring and autumn, when considerable numbers 

 are going northward or southward at the same time, and 

 they feed on the smaller birds, which are also massed in 

 unusual crowds on the same errand. Exceptional abundance 

 of some form of prey — as, for example, the field voles in the 

 famous years when they swarmed in the south of Scotland — 

 will also attract large numbers of birds of prey. But this is 

 precisely an exception that proves the rule ; the birds of 



