THE BIRDS OF THE STOUR VALLEY (ESSEX ONLY). 137
I received news from a correspondent that a steady migration,
including Arctic Skuas, was taking place daily off Cley. Al-
though I did not expect to have much success, because if this
migration struck the Essex coast we should have more Skuas
recorded, I hurried off to Manningtree on 19th September, and
spent the two following days on that point at the entrance to
Hamford Water which I have already described, but the evidence
I obtained was completely of a negative nature ; there was not
the slightest sign of migration. This was no disappointment,
for it is important that we should have evidence, even though
it be negative. Probably this September migration, which is
seen at such points as Cley, follows the Norfolk coast to its most
easterly point and then moves directly southwards over the
sea. Dr. Eagle Clarke's observations conducted on the Kentish
Knock Lightship, which, it will be noticed, lies almost due south
of the east coast of Norfolk, prove that the north to south
movement of this date strikes this lightship. Speaking of the
Arctic Skua, Dr. Clarke (Studies in Bird Migration vol. 2, p. 38),
states : "Present daily from 24th September onwards, chiefly
engaged in bullying the Kittiwakes and sometimes the Lesser
Black-backed Gulls." A glance at the map will show that if
this is the route taken by this particular migration, the birds
would pass a long way out at sea off the Essex coast.
I must again quote Dr. Clarke (vol. 1, pp. 83-4) : "The East
and West Routes :—The southern section of the east coast of
England is the scene of the arrival in the autumn, and departure
in the spring, of a very considerable number of bird-travellers.
These form a group of migrants of a particularly interesting
description, consisting of certain species which cross the southern
waters of the North Sea by a more or less direct east-to-west
flight in the autumn, and by movements in a reverse direction
in the spring. They are Cental European birds, and in the
autumn are either on passage to lands beyond our shores, or
are bent on passing the winter with us. Day after day in late
September, and throughout October, this stream of migration,
which is often of great volume, is observed sweeping past the
numerous lightships stationed off the coast between the Straits
of Dover and the Wash, towards the coasts of Kent, Essex,
Suffolk, and Norfolk. It has its centre on the Essex coast and at
the mouth of the Thames, and towards these the migrants