THE HISTORY OF ESSEX HERONRIES.
257
The greatest number of nests was in 1915, when there were
seventy-four and the lowest in 1934 when there were twenty,
the average for the forty-four years being fifty. Ten is the
greatest number of nests seen on any one tree.
Writing in 1872, J. E. Harting stated that the trees used
were elms and wych-elms, but now almost all the nests are built
in oaks, rarely in chestnuts.
Young were seen in flight from tree to tree on 1st April,
1898. In 1928 when there were sixty nests on thirty-three
trees a count was made of the young birds found dead, the figure
reaching twenty-three.
Percy Thompson states that a dissection of pellets from
this heronry shows remains of water beetles, bones of water
vole, mole and other mammalian fur, claws of mole and the
claw of the rat ? ; bones of birds are included. One of the
pellets is interesting from the fact that in it is embedded a
portion of the sternum, with its characteristic spine, of the great
water beetle (Hydrophilus piceus) which is rare in the district;
another contains an elytron of the commoner aquatic beetle
Dyticus marginalis.
There is a large rookery in close proximity to the heronry,
but the Herons do not seem to have been adversely affected
by this feature. It is reported that a reduction in the Rookery
coincident with that in the Heronry has been noticed in recent
years. The majority of the Herons quit the nesting ground
at the close of the season, but a few remain throughout the
year. The heronry, which comes under the control of the
Conservators of Epping Forest, is excellently protected.
The Birch heronry has been in existence seventy-four years
and twice during this period the Herons have changed their