12
BIRDS AS THE FOOD OF FISHES
BY WILLIAM E. GLEGG
[Read November 30th, 1946]
THE result of many years' observation at reservoirs, parti-
cularly the Essex series in the Lea Valley, convinced me
that much of the destruction of young aquatic birds, such as
coots, moorhens, grebes and ducks, was attributable to pike,
although other enemies such as rats and carrion-crows were also
responsible. Strong as my conviction was I could not produce
that evidence which would be accepted as proof.
The first personal experience which could be adduced as
evidence occurred in an unexpected manner. On 30th May,
1930, my wife and I were enjoying our lunch at the edge of a
lagoon at the Campo dell' Oro, Corsica, while watching a party
of white-winged black terns, which were careering about with
the buoyant flight characteristic of marsh-terns, when one swept
to the surface of the water. To our astonishment, for marsh-
terns are unknown to dive, the bird disappeared under the water.
It did not reappear and I am driven to the conclusion that it
was seized by a large fish.
In 1943 the subject attracted some attention, and I decided
to institute an investigation. Fortunately, I did not confine
myself to ornithological channels and gleaned helpful information
from ichthyology. As a result of my enquiries I have obtained
evidence of 39 species of birds having been attacked by nine
kinds of fishes. As would be expected, most of the birds attacked
are aquatic, but the list includes a number of species which are
strictly land birds. The information at my disposal deals with
many parts of the world, but for this contribution it may be of
special interest to consider separately the evidence which has
been obtained in the British Isles.
I find that for this country it has been recorded that 18 species
of birds have been attacked by seven species of fishes, of which
three were fresh and four salt water. The fresh water fishes are
pike, eel and trout and the salt water are angler, cod, angel-
fish or monk-fish and thresher. Of the fresh water fishes, the
pike is the greatest enemy of birds, so much so that it might be
described as the fresh water shark, and in this respect the angler
comes first among marine fishes. The amount of evidence of
eels and trout attacking birds is small, but a waterhen has been
found in the stomach of the former. The depredations of pike
reach remarkable dimensions and on occasion are of an extra-
ordinary nature. In July, 1824, on the Derwent at Malton a
pike was seen to dart out of the water and seize a swallow.