164 MIGRATION AND DISTRIBUTION 



by others. It is, indeed, hardly too much to say he 

 despaired of an answer ever being brought forward to 

 the great question in his own time, at all events. 



With much that you say I wholly agree, though I 

 can't attach much value to what has hitherto been 

 written about " Land routes " of migration and so on. 

 There may be such things, indeed, I will go so far as to 

 say that such things probably exist, but as yet we really 

 know next to nothing about them. The worst of it is, 

 I don't see my way at present to knowing much more, 

 for want of well-placed and trustworthy observers. 

 The ordinary man who records his first Swallow and so 

 on, however faithful he may be, goes very little way to 

 help, and how to improve him I don't know. 



Even if I had kept a record of my own observations 

 on birds travelling by night, since I took up my permanent 

 abode at Cambridge, it would tell me very little that 

 would be of use ; and I take it that in all that time few 

 people have had opportunities so good as mine ; for my 

 habit of working late at night and, except in really cold 

 weather, with a window open, is not one that many 

 indulge. I can only, as a general result, say that when 

 the sky is clear one hears nothing ; but given a cloudy 

 sky, from the end of July to the middle of October, the 

 chances are one hears birds fly over. What birds they 

 are it is nearly always impossible to say, because the 

 generality seem to use a different language when travel- 

 ling. 



After long experience I have come to the supposition 

 that certain notes are uttered by Oyster-catchers ; but 

 I never heard an Oyster-catcher utter such a note by 

 daytime or when he is at home ! It is very rarely that 

 one catches an unmistakable note, a Cuckow's, a Red- 

 shank's, or a Golden Plover's, yet hundreds of them must 

 be passing over. 



There is plenty more to be done in the migration way, 

 if we only knew how to do it.* 



* Letter to J. A. Harvie-Brown, September 9, 1900. 



