264 THE ESSEX NATURALIST.
remarkable. All the nests were built in small, frail hawthorns;
none of the nests being more than twenty feet from the ground
and many considerably less. The nests swayed when one
pushed against the trunks of the trees. The colony at St.
Osyth Priory is perhaps the largest in Essex. Its beautiful
situation may be responsible for the increase which has occurred,
as the birds are free from interference and in proximity to good
feeding ground. The Birch heronry, which comes second in
point of age, was the largest the county has been known to possess.
In 1890 there were 170 nests, but the number has been dwindling
for many years, and in 1928 there were no more than nineteen
nests. The smallest heronries are those at Skippers Island
and near Gosfield Park. Heronries come and go. We know
that as far back as 1594 there was one at Tolleshunt Darcy,
and we also know of the past existence of several others.
Thirteen is the largest number of nests known to have been
constructed on one tree in the county and nine species of trees
have been used for nesting purposes. The number of Herons
nesting in the county does not seem to have altered very much,
for in 1890 there were about 224 nests, whereas in 1928 there were
216 nests. It would seem, however, that there is now a tendency
to smaller colonies, as in 1890 there were four and in 1928 six,
and those which have been subsequently discovered are small.
Only three other counties, namely Norfolk, Somerset and Sussex,
have more nesting Herons than Essex.
There are six gulleries and they are all claimed by the Black-
headed Gull. They are situated in close proximity to the sea.
In four cases the nests are constructed on the short turf of the
saltings and in the other two among the reeds and sedge of the
fleets. A rough estimate shows that the total number of pairs
nesting in the six colonies would be about five hundred. The
largest colony is on Horsey Island, Hamford Water, where
about 150 pairs nest. The history of the gulleries is obscure.
It would seem that Black-headed Gulls have nested in Hamford
Water, although not on the present site, since 1662, when they
nested on Pewit Island. What may be the most recent of the
gulleries is situated on the north bank of the Crouch. It is
probably the nearest colony of its kind to London. It would
appear that the Black-headed Gull was a commoner breeder