58 REPORT ON THE MIGRATION OF BIRDS. 
observation also proves that the earlier arrivals, as a rule, refer 
to the young of the year, and the later to old birds, but with 
many exceptions. 
Birds also continue persistently, year by year, to follow the 
same lines of flight both in the spring and autumn, and at least 
nine-tenths of the arrivals at the latter season come directly 
from the east or from points south of east, moving to the west 
and north-west. In the spring, when leaving the east coast, 
they travel in the reverse direction, but still following the old 
lines. The occurrences of migrants coming from points north 
of east is quite exceptional. 
The fact of a double migration or passage of birds of the same 
species across the North Sea in the spring and autumn, both to 
the E. and 8.E. and W. and N.W., is very clearly established 
(see General Remarks, 1884 Report, East Coast of England, pp. 
69 and 70). This phenomenon is regularly recorded on the 
whole of the east coast, but specially observable at those lght- 
vessels which are stationed in the south-east district included in 
this report; at the same time, it is invariably persistent and 
regular year by year. 
An examination of the reports, seven in number, already 
issued by the Committee, will show the extreme reeularity and 
precision in time during which the migration of each species is 
carried on. This applies both to the vernal and autumnal 
passage; in the vast majority of cases the commencement of 
the migration occurring on the same day, or within a few days, 
of a fixed period, so that it would not be difficult to tabulate in 
advance with almost certainty the normal movement or migra- 
tion of each species. 
The arrivals of rare and occasional visitants have been unusu- 
ally few ; perhaps those of chief interest are the occurrences of 
the Arctic Bluethroat and Desert Chat at Spurn, the Black- 
Bellied Dipper in Lincolnshire, the Woodchat Shrike, Serin 
Finch, and Spoonbill in Norfolk, and the Spotted Eagle in 
Northumberland. 
In the spring the earliest occurrence of our summer visitants 
is as frequently recorded at the northern as at the southern 
stations ; instance the arrival in 1885 of the Swallow at Spurn 
on April 8th; the Swift, several, on April 20th; and the 
Cuckoo at Whitby on April 8th; and in 1886 the arrival of 
