THE GREY-BACKED WAGTAIL. 
157 
very pure and perfectly free from even the slightest admixture of black. 
The greater wing-coverts are margined with white, and in the closed wing 
the amount of white on this part of the plumage is much less conspicuous 
than in ikf. leucopsis. 
There has been much controversy as to whether M. dukhunensis, the 
bird found in India, is identical with M. alba^ the bird found in Europe. 
It has been contended that the Indian birds have much more white on 
the wing than the European ones, and that they differ in some other 
minor points, such as the coloration of the young. After examining as 
many specimens from both continents as were accessible to me, I am of 
opinion that the two supposed races are identical, and that in the case of 
the majority of the birds it is impossible, without looking at the labels, to 
tell with certainty from which continent they have come. On the whole, 
perhaps, the Indian birds have whiter wing-coverts, but this is a character 
liable to much variation and consequently not of much value. A point 
insisted upon by Mr. Brooks, an advocate of the specific distinctness of the 
races, is that the young of M. alba are yellowish about the head, whereas 
the young of M. dukhunensis never have this yellow tinge. A great pro- 
portion, however, of the birds of this species that are obtained in Burmah 
have the yellow tinge well developed on the head, and I can attach no 
importance to this diagnostic point. 
The Grey-backed Wagtail is sparingly distributed over Pegu during the 
cold weather, and is much rarer than the preceding species. Mr. Davison 
found it in Tenasserim as far south as Moulmein. Capt. Wardlaw Ramsay 
procured it in Karennee. It is probably spread over Arrakan. 
In winter it is distributed over a large area. It occurs over the whole 
of India, South-western Asia, Southern Europe and North Africa. It also 
appears to be found pretty abundantly in China and Cochin China. In 
summer it passes to Central and Northern Europe and to Northern Asia, 
but very little is known about its distribution in this latter continent. 
Mr. Seebohm found it on the Yenesay river as far north as latitude 7I^°. 
He observes : — The geographical distribution of this bird is very curious. 
As Middendorff did not find it, we may take the watershed between the 
Yenesay and the Layna as its eastern boundary, whence it extends west- 
wards as far as the Atlantic on the continent of Europe, but only appears 
accidentally in the British Isles. As you ascend the Yenesay from the 
Arctic Circle this bird abounds on the banks of the rivers until you near 
Yenesaisk (about lat. 59°), when it suddenly disappears, and its place is 
taken by M. per sonata. Erom Yenesaisk to Krasnoyarsk and westwards 
until you cross the meridian of Calcutta, M. per sonata abounds, after 
which, across Siberia and Europe, you find no white Wagtail but 
M. alba:' 
In habits this species is very similar to M. leucopsis, frequenting the 
