96 The Scottish Naturalist. 



ficatlon also pass further than others to the southward in 

 winter. Thus the migratory Fieldfare, visiting regions north of 

 the limits of the Thrush and Blackbird, on their southward 

 migration, leave their more sedentary relatives behind. The 

 Brambling, which passes the Chaffinch in Norway, leaves it also 

 in Europe, and crosses the Mediterranean every winter to the 

 Barbary States. The Egyptian and Collared Turtle-doves' 

 remain throughout the year in Syria and north Africa, but the 

 Common Turtle {T. auritis Temm.) so abundant in those 

 countries in summer, never leaves a straggler behind in 

 November, and yet in spring advances a thousand miles nearer 

 to the Pole than they do. 



Though this is one of those laws of migration so little under- 

 stood, we have a very striking exception to it in the Snow 

 Bunting ( Flectrojyhanes nivalis), bearing on the theory that 

 constitutional causes in some measure influence the extent of 

 migration in birds. The Snow Bunting never much exceeds 

 the limits of the central parts of Europe on its southern migra- 

 tion, there only being three instances of its being found so far 

 south as Malta * (and I have seen no record of its ever having 

 been noticed in Africa) ; and yet the Wheatear, who goes equally 

 far north, nesting almost side by side with it far within the 

 Arctic circle, goes into the interior of Africa, and is never found 

 in Europe in winter. While to the westward, Canon Tristram 

 found it in the Sahara (Ibis, 1859, p. 300); to the eastward, 

 Mr. S. Allen (Ibis, 1864, p. 238) says, it does not even 

 winter so far north as Egypt, but goes into the interior 

 of Nubia, not returning to Egypt till the beginning of 

 March. Mr. Cavendish Taylor and Mr. Shelley mention 

 the same fact (Ibis, 1867, p. 61, and 1871, p. 51). Why 

 is this ? The Wheatear, though insectivorous in its habits, 

 would no doubt get a sufficiency of food suitable to it 

 in the extreme south of Europe, or northern Egypt, during the 

 winter, but being of a more delicate constitution than the 

 Snow Bunting, is compelled to seek a warmer climate. The 

 Snow Bunting, again, is granivorous : but so is the Bram- 

 bling. The former, strong and robust in habit, is enabled to 

 stand our winters with impunity, some few even wintering as 

 far north as Shetland : the latter winters in many parts of 

 this country, but never in Shetland ; and on the continent it 



Ibis. 



