PART THREE 



INTRODUCTION 



If I should count them they are more in 

 number than the sands. 



Psalm 139:18 



IT WOULD have been most satisfactory if, in Part III, we could 

 have supplied a complete check list of the parasites of British birds. 

 Such compilations make dull reading but from the practical, scientific 

 angle would provide a valuable and badly needed piece of work. The 

 chief bar to drawing up a check list of this type is the vast numbers of 

 scattered records of parasites recorded abroad from birds on the British 

 list, coupled with the paucity of genuine records from birds in Britain. 

 A list restricted to the latter parasites would be altogether misleading 

 and practically valueless, even if the species likely to occur in this 

 country were included, whereas the compilation of the former list 

 represents a herculean task few would feel inclined to undertake — 

 certainly not the authors. 



The following chapters are, therefore, intended to give the reader a 

 rapid survey of the main groups of bird parasites in Britain and to point 

 the way to further ecological and systematic work, and, in particular, to 

 emphasize the need for further collecting and the accurate identification 

 of specimens. 



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