228 
MIGRATION OF BIRDS 
The last specimen to be seen was collected on April 18. 
It was solitary, and is in almost full plumage. Apparently, 
the first sign of coming maturity is the presence of the red 
throat, followed later by a lessening of the spots on the breast, 
which area later becomes pinkish brown and the rest of the 
plumage generally more fulvous. 
Flocks pass through Egypt in April. 
5. The White Wagtail ( Motacilla alba) breeds in the 
north of Europe and in England. Said to breed in Palestine, 
also breeds in Asia Minor. They arrive in breeding areas 
in April, leaving in September. Not a very common migrant 
to these parts ; most birds make their appearance in November 
and remain till February. 
It will be noticed that some males are in entire breeding 
dress in January, while others collected at end of February 
are scarcely showing any signs of assuming the summer 
plumage. 
6. The Blue-headed Wagtail ( Motacilla flava) breeds 
in suitable localities throughout Europe. Arrives in May 
and departs in September. Large numbers pass through 
Egypt, arriving in these parts in October, usually accompanied 
by the ashy and yellow species. 
So far as I could see, there were no adult birds in full dress 
in the flock that arrived in the Nairobi District last October ; 
all were young birds and hardly to be distinguished from 
young M. raii. By January some birds had commenced to 
assume the adult dress, and could then be picked out easily 
from M. raii. In these, as in others of this group, fully two 
thirds showed no signs of assuming the adult breeding dress 
when they left Nairobi in March. 
7. The Ashy-headed Wagtail (Motacilla cinereaca / pilla) 
breeds in the southern portion of Europe. It is not a common 
migrant to these parts. A few are to be found with M. raii. 
I collected a single specimen in full plumage on April 25 — 
probably a stray bird ; they seem to be more plentiful in the 
Kisumu district than elsewhere. The series exhibited contains 
specimens collected between October and April 1916-17. 
8. The Black-headed Wagtail ( Motacilla melanoce'phala) 
although not admitted by some authorities as entitled to sub- 
