BIRDS. 



301 



regarding the distribution in Tay, nor add much to our appreciation 

 of the paths followed on their spring and autumn migrations. 



My later information, dating between 1900 and the present time, 

 tends to show that an increase was sudden, and afterwards rapid, 

 especially about 1902-3; and further proof reached me in 190-i. M}' 

 correspondents remark upon the fact almost uniformly. And so far 

 as I at present am aware, I believe that I have quite the furthest 

 south record in Tay, and of their having bred there for the first time 

 in 1904. In fact, not only do they appear to have reoccupied many 

 long-deserted sites and hills, but they have given evidence of fresh 

 energy and further extension ; but there is one thing I hare not 

 ascertained^ and that is : Whether any diminution in their numbers 

 has taken place further to the north 1 That, I fancy, may be quite 

 possible, when we take into consideration the cold summers of these 

 years, as I have before pointed out (see Fauna of the Nmih-West 

 Highlands and Ski/e) under another species — viz. the Woodcock, which 

 was known to nest in most abnormal numbers, here and in other 

 parts of Central Scotland, in 1903 and 1904. My correspondents 

 when writing make some such remarks as the following: "I cannot 

 ascertain that the Dotterel has ever been found on this hill, nor 

 about this glen before " ; and another says : " It does seem as if they 

 were coming down to lower grounds," and so on. 



These movements may yet prove an increase, or otherwise a 

 permanent extended area ; or, what seems equally probable, they 

 may only result in a temporary abandonment of formerly more 

 exposed heights or aspects, and be followed by a retreat once more 

 to these in the event of the summers again becoming warmer ! I am 

 careful, however, to give them prominence here as undoubted facts, 

 so far as I have been able to ascertain them, but withholding details 

 which might lead to different causes of retreat or disappearance. 

 I think the subject is of sufficient interest to such of our naturalists 

 as find pleasure in watching any causes and effects which have a 

 bearing upon migration, distribution, and the processes of dispersal, 

 and which vre have endeavoured to maintain as a point in this 

 series. The land-routes of migrants do not appear to me so great a 

 mystery as some naturalists appear to consider ; but they are quite 

 right to endeavour to satisfy themselves, though that can only be 

 well done by those who have been, or who can be, constantly in the 

 field, or who can be sure of obtaining their facts from reliable sources, 

 and who know how rightly to read them when brought together and 

 arranged. 



I do not mean to say with any degree of definiteness that this 



