MIGRATION OF BIRDS 
229 
specific rank, appears to be quite distinct, and this is supported 
by its habits when in this country. My experience is that 
they are not common, that they keep to themselves, not 
mixing with others of their own family, and that they appear 
in this country much later on than do other species, and they 
do not travel so far south. 
They breed in the Eastern countries of Europe. 
9. The Yellow Wagtail ( Motacilla raii) is a summer 
visitor to the western countries of Europe where it breeds. 
They arrive in May and depart in September. Most go to 
West Africa, but during the season last year hundreds arrived 
in the Nairobi district ; in October they were present in large 
numbers right up to the end of March, and, when they left, 
scarcely half were in full plumage. 
Odd birds were procured by me through April and May. 
10. The Grey Wagtail ( Motacilla melanope) appears to 
be quite the most rare of this group, few visiting this country. 
As a summer resident they inhabit the countries from South 
Sweden to the Mediterranean. I have never seen them in 
flocks numbering more than four to six individuals ; most 
frequently they are seen singly. Of the two specimens ex- 
hibited one was collected in December, the other as late as 
June. The latter is not in anything like full plumage. 
We now pass on to another group, commonly called Butcher 
Birds or Shrikes. 
11. The Lesser Grey Shrike (Lanius minor) is widely 
distributed, breeding in South and Central Europe, north to 
Siberia, and east to Asia Minor and Turkestan. 
In winter it migrates to tropical Africa, arriving here in 
October. They can usually be found in pairs or small flocks 
up to March, but I have also obtained them in April and even 
in May. 
12. The Great Grey Shrike ( Lanius excubitor). Ex- 
amples of this species have been reported from this country, 
but it seems to me very doubtful whether they are the European 
bird. There are one or two local forms extremely like it 
which are resident in this country and whose numbers increase 
at certain times in the year ; but, having collected a very large 
series, I was unable to find a single specimen which agreed 
Vol. VI.— No. 12. R 
