170 On the Ornithology of Wilts {^Tetraonidce]. 



1863 this handsome species was almost unknown, not only in these 

 islands but on the continent of Europe ; when suddenly in the early 

 summer of that year a vast irruption of them occurred, more 

 especially on our Eastern coasts ; and it subsequently appeared that 

 this strange invasion extended over the whole of Central Europe. 

 Driven from its home in the steppes of Tartary, if not in the more 

 Eastern countries of China and Siberia., where it also abounds, this 

 horde of wanderers started westwards, and spreading themselves 

 over some twenty degrees of latitude, the more advanced portion 

 penetrated as far as our island. What numbers migrated in this 

 extraordinary manner ; what vast flocks in all probability started 

 on this lengthened journey ; how many halted on the way ; it is 

 impossible even to guess : but in a most masterly paper on the sub- 

 ject drawn up by my friend Professor Newton, the talented editor 

 of the Ibis, and published by him in that journal,' he has 

 satisfactorily proved that several hundreds are known to have 

 reached our shores, after a flight of, at the least computation some 

 four thousand geographical miles. What could have caused this 

 eccentric movement of the Asiatic species of Grous we are consider- 

 ing, this "Tartar invasion," or "Scythian exodus," as Mr. Newton 

 styles it, it is beyond my power to explain : whether the prevalence 

 of unusual easterly winds, or other atmospheric commotions impelled 

 them on their westerly course, as some have suggested ; or whether 

 the colonization by Russia of large tracts of eastern Siberia, and 

 the reclaiming of waste lands, once their haunts, as others have 

 surmised : or whether the remarkable drought that prevailed over 

 central Asia that summer, had dried the freshwater lakes, and 

 scorched up all vegetation, as others have concluded ; or whether as 

 Mr. Newton inclines to think, the natural overflow of an increasing 

 species, prolific as are all of its genus, and exempt in a great 

 measure from the enemies and risks which are apt to beset ground 

 breeding birds, forced it to drive forth as colonists its superabundant 

 numbers, I will not now stop to argue. Enough for us that, as in 

 early times the tide of human migrations set in steadily from the 

 east, and starting from the shores of the Caspian and the valleys of 

 > Ibis, vol. vi., pp. 185-222. ' 



