16 ANNALS OF SCOTTISH NATURAL HISTORY 



mainland of Argyle, and in most of the isles simply swarms, 

 as may be gathered from our own notes in our " Fauna of 

 Argyll and the Inner Hebrides." But it is interesting still 

 to find traces of farther extensions up towards the hills, from 

 the valleys and from the haugh-lands to the mountain-slopes 

 or remoter shepherds' houses and shooting- lodges, in quite 

 recent years ; filling up, as it were, blanks in its universality 

 right and left of its main lines of least resistance, owinsr to 



o ^> 



the pressure upon the centres of earlier colonisation, and 

 congestion. 



Whilst the vanguards pushed on and populated the 

 straths in the earlier stages of their advent, the later 

 younger arrivals, whether reared on the spot, or migrants 

 from other nurseries, were obliged to press up the hill-sides 

 and more remote glens, as we believe is the case with many 

 other more or less assertive species. 



A difficulty now is suggested here, which at present we 

 will only mention : Whence came the vanguard of Starling 

 immigration to Argyle mainland, and whence came the 

 immigration to Argyle Isles ? Did they both come from 

 the same sources and the same directions, or from two 

 diametrically different sources and directions, viz. from the 

 " Clyde " and South- West entirely, from the Outer and Inner 

 Hebrides entirely, or was its population drawn from the two 

 sources South-East and North- West alike ? More minute 

 and more numerous data are required, we believe, before we 

 can say whether or not the Starling population on the west 

 of the backbone of Scotland drew its battalions from the 

 older and equally vast centres of long, long standing on the 

 pathway of the great autumn migration which, as we believe, 

 is well proved, occurs down the range of the Outer Hebrides 

 and crosses salient points of the Inner Isles (following the 

 shore-lines and nearest shore-cuts), past " Clyde " to the Mull 

 of Galloway, and thence, as we have endeavoured to indicate, 

 shooting off to Ireland ; or whether Argyle mainland is 

 indebted to an advance over the mountain passes between 

 the gates of the Highlands in the east and the wild west 

 glens across the great backbone of Scotland ? 



