BIRDS OF THE THAMES VALLEY (ESSEX ONLY). 157
numbers of Starlings and Skylarks which were crossing the
North Sea, from the Kentish Knock lightship as far as South-
end, and he adds that the birds were still trooping up the Thames
valley in considerable numbers when he left the ship.
During the course of my observations a little confirmatory
information has been obtained, although all my records refer to
emigration. In spite of the fact that all the movements which
I noticed were of birds making their way to their winter quarters
farther south, yet the river was followed by birds in both directions,
that is to say, some species took their departure down the Thames,
while other forms proceeded westwards. On September 9 1927,
a remarkable emigration of Swallows was noted, birds passing
seawards constantly during the five hours I was on the sea-wall
between Tilbury and Mucking. An example of movement in
the opposite direction, namely towards London, is that of terns.
Movements of these birds were observed in both 1926 and 1927.
At the end of the third week of August of the former year terns
were noted as high up the river as West Tilbury steadily making
their way up stream in small numbers. A similar movement was
noticed early in September, 1927 at East Tilbury when the river
was alive with these birds. Curiously enough in each year a
particular part of the saltings was utilised by the birds to settle
on. Other movements will be remarked upon in the systematic
list.
The proximity of the district to London made it possible to
carry out all the work by means of day visits. Observations
were made during all months of the year except June.
A total of 94 birds was identified, and, following the pro-
cedure of previous papers, I have mentioned every species identi-
fied; the status of those unaccompanied by data will be taken to
be normal.
Hooded Crow (Corvus c. cornix L.). One seen on Stanford-le-
Hope Marsh, 26/12/26. This is the only one I have seen on the
Thames at any time, which confirms the evidence of previous
papers that on the Essex coast the Hoodie is scarce in the south,
becoming gradually less so until we reach the north, where it is
fairly common. My observations have brought to light the very
remarkable fact, difficult to believe unless actually experienced,
that while on the north bank of the Thames this species is very
rare, yet on the south side it is not uncommon, and may be almost