FAUNAL POSITION. 



149 



present area and certain localities on our west coast — such as the 

 island of Tiree — which lie at the west or south-west extremity of 

 the great main trough of the Great Caledonian Glen. Evidence of 

 this extension, we think, can be made patent to those of our 

 readers who care minutely to follow the history of extension of 

 range — whether of breeding species or of merely migratory ones — 

 both as regards woodland species. Waders, Raptors, or certain 

 species of water-fowl. There are others, no doubt, such as the 

 Grey Phalarope, and species of more western and north-western 

 distribution, to which these remarks are riot applicable — conditions, 

 or alterations in conditions — which we trust it is not necessary to 

 insist upon with those who appreciate the general direction of 

 our argument.^ 



There are fluctuations also, dependent upon meteorological con- 

 ditions, which may, and do, cause extraordinary departures from 

 the common law — what, indeed, may be looked upon as causing 

 abnormal occurrences of species far out of their usual tracks. 



A sketch of the 'Witch-ground' occurs in an article by Mr. 

 George Sim on ^ Lumpenus lampetriformis on the Coast of Scot- 

 land' (Joicrnal of the Linncean Society, vol. xx., 'Zoology,' No. 116, 

 p. 43 q.v.). 



We may here add, as bearing on what we have just mentioned, 

 that local observers during a long series of years have noticed that 

 there has been a considerable change among the birds of their 

 district since they were schoolboys. ' Some sorts,' writes Mr. 

 Mackessack, ' which were fairly common then have almost dis- 

 appeared, while others, which were then unknown, or at least very 

 rare, have now become fairly common.' 



This experience of Mr. Mackessack is shared by most, if not all, 

 of our observers who have been long resident in one district, and 

 we mention it thus pointedly, as its bearing upon migration and 

 extension of range is pertinent to our argument. 



^ It appears to us to be somewhat significant that so many of our rarer species 

 bred in Strathspey and within our present area much more commonly prior to 

 1851. This, we know, is the case with the Woodpecker, the Black -throated 

 Diver at Lochindorb, and such species of our Raptors as the Osprey, Kite, Hen 

 Harrier, and others which now have disappeared or become much scarcer, and of 

 such thoroughly isolated species as the Crested Tit, Honey Buzzard, etc. 



