MAPS OF DISPERSAL. 



Ixxxv 



day. The map also shows a very much more recent colonising, taking 

 evidently an absolutely opposite direction, viz. from congestion in 

 the south, and expansion northwards. This map therefore shows 

 two distinctly different movements in dispersal of the same, or (?) 

 closely related, races of Starlings, — one from the north and east 

 (and possibly from Faroe also (?) ), and one by purely increase 

 and extension from the south. As far as carefully collected dates 

 can guide us (and they seem to me sufficient) this map is deeply 

 interesting. 



In the map of the Tufted Ducks' nesting-dispersal, the advance 

 is shown of a species coming for the most part from the south 

 by simple increase, but suggesting also — from the peculiar circum- 

 stance that Caithness and Foeth hold the oldest as well as the most 

 numerous tenancy of this species — suggesting, I say, more than 

 merely a south-to-north direct increase, and something of a possible 

 arrival from the east, along the two very principal routes which are 

 followed by migrants at the present day — as I long ago pointed out 

 and still maintain — viz. the Isle of May and the Pentland Firth. 

 But it is strange, is it not, that the great open, g^-ping of the 

 Moray Firth is not equally honoured by their earlier arrivals ? The 

 Tufted Duck seems a bird amongst Ducks of sluggish habit, and not 

 a perfervid migrant. Once at a place, it seems inclined to remain, 

 and the rushy, reedy lochs of Caithness seem very easily indeed to 

 have arrested their (perhaps involuntary) migratory flight. Once 

 arrived, they remained happy and stay-at-home. I only ask my 

 readers, or rather such as really care to make a study of such 

 matters, to consult also the continental distribution of the species, 

 and see what the conclusions are which they may come to. I may 

 frankly state, conclusions have been almost forced upon me, with 

 ever-increasing conviction, since I first took up the subject of " Dis- 

 persal of Species," and I have tried to illustrate these convictions all 

 through this series from first to last ; and I have already gone back 

 and tried to indicate the progress of my views in this opening 

 chapter of the final volume. 



The last of the maps illustrates Mr. Eagle Clarke's record of the 

 invasion of Little Aicks. These Arctic strangers have not been made 

 happy, nor have they remained to dwell with us. The object of 

 this illustrative map is both to show their enforced flights and 



