THE BIRDS OF THE LEA VALLEY RESERVOIRS. 185
the only inland records of these species for the County, and
the Red-crested Pochard had been previously identified twice
only in Essex. It will be noticed that the list of ducks includes
six surface feeders and ten diving ducks. It is not surprising
that there should be a marked difference in the status of the
two representatives of our next group, the Steganopodes, namely,
the Cormorant and Shag, as the latter is a much more marine
species than the former. The Cormorant has been noted in
every month of the year except July and almost annually,
while the Shag owes its inclusion here to a single occurrence.
Of the five species of Grebe three are rare and two are
residents. The Slavonian has been identified on three, the
Red-necked on four occasions and the Black-necked once only.
The Little Grebe breeds in small numbers, becoming more
numerous in winter, but the Great Crested is the chief feature
of this group and one of the more noticeable features of the
reservoirs, particularly during the nesting season and tire
period of the autumnal migration. It is difficult to estimate
how many nest annually, but I have put the figure at from
twenty to twenty-four pairs. Nests with eggs may be seen from
April to September. Nesting operations are mainly confined
to the southern end of the group of reservoirs. The numbers
which appear during the autumn migration vary from year
to year, but they are increasing and as many as 150 have been
counted. The appearance of the Divers at the reservoirs is a
very rare event. The Red-throated has been identified on two
or three occasions and one has been obtained. The Black-
throated and Great Northern have each one occurrence to their
credit. All the records of these species refer to the winter
months.
The long list of Limicoline birds, waders, including twenty-one
species, demonstrates still further the influence of the inland
fresh water on the ornithology of the County. Some of the
information regarding this group has come to us fortuitously.
As the result of droughts in 1929 and 1933 the water-level in
the King George Reservoir was so far lowered as to expose
much mud, and during the autumn many waders, the majority
of which would have passed unnoticed, were identified. The
greater part of the waders are passage-migrants, and as such
most of them are irregular, and occur almost entirely during the