Evening star., 1935-07-28
Death Trap for
Birds
BY Frederic J. HGskin.


tional Capital, arranged partly for deco
rative purposes, but largely to prevent
airplanes from crashing into the huge
pile on dark nights, may have saved
the lives Of some aviators, but they have
had the reverse effect on birds. A
study of migrating birds in Washington
has revealed that the food lights serve
to attract the birds which crash head
long into the Monument and fall, either
dead or injured.
To what extent the birds consciously
use the reflected light of the Monument
as a beacon directing them on their
way, and to what extent they may be
dazzled or blinded, has not been def
nitely established. 1t has been estab-
lished, however, that more bird casual
ties occur when the Monument Is tlluml-
mated than when it is not.
1t is thought probable that the birds
in some cases may be caught in wind
currents eddying about the Monument
and dashed against the stone when at
tempting to avoid the obstacle. Their
efforts to make a laSt-second Swerve TO
avoid the structure prove unavailing.
According to one observer, Miss
Phoebe Knappen, the bird mortality at
the Monument is greater on nights OF
storm Caught in the wind, the birds
are dashed against the stone with great
force. Even on calm nights, fast-fying
birds may kill themselves from the force
of their own momentum, but the death
rate appears higher when the wind
force is added.
When the SlightneSS of the space occu-
pied in the air by the relatively slender
shaft of the Washington Monument, in
comparison with the unoccupied space
all around, is considered. it seems odd
that so many birds should come to their
deaths in this manner. This fact lends
credence to the theory that the lighted
sides of the Monument have the effect
of attracting the birds.
In Path of Heavy Migration.
Observations show that birds are af-
fected by illumination. For example, on
moonlit nights the birds fly at a much
higher altitude and, thereby, avoid col
liSion with structures. The fact that
they fly nearer the ground on dark
nights is believed TO indicate that they
utilize the glow of artificial lights on
human habitationS, streets and electric
signs to guide them. Just how much
the death of the birds is due to use
of lights as aids to flight and just how
much to a sort of f1amelike attraction,
as in the case of moths and other
insects, is q matter for conjecture and
further observation.
The District of Columbia is in the
path of huge bird migrations, Spring
and Autumn, and observers often check
the flights, noting the arrivals. It was
on the night of September 5. 1882. that
the effect of the flood lighting of the
Monument on the birds was first noted
There had been a severe thunderstorm,
accompanied by high winds. A some
what dramatic result was that, in addi-
ton to the heavy precipitation of rain,
it literally rained birds about the base
of the Monument. Eighty eight of these
birds were identified as belonging to
l6 different species. These formed
about one-third of the total which had
met their deaths in that single stormy
night.
After that the Monument was visited
nearly every night by observers who
usually patroled the base, but sometimes
mounted to the top, SIS feet aloft, and
listened to the cries of the birds as
they sailed past or over the shaft. This
type of observation was continued in
the Spring and Fall seasons for two
years, and in the period from September
S, 1892, to May 27, 1884, no less than
718 birds which had dashed against the
Monument had met their deaths. Some
we're too badly mangled to be examined
or preserved for the Survey or National
Museum collections. In some cases,
prowling cats and dogs caught the
falling birds and preyed upon them.
The best estimates which the observers
could make was that at least 500 birds
lost their lives at the Monument in
the single migration season OF the
Autumn of 1892.
The amazing fact is that the dead
birds collected over this period were of
So distinct kinds. The District OF CO.
lumbia is rich in bird life. There are
over 100 species to be found in the
District in the Summer months, and
this number is nearly tripled if the birds
of passage are added. The high num-
Der meeting their deaths against the
narrow shaft of the Washington Monu-
ment indicates that light has an attrac-
ton for most birds, regardless of species.
A number of bats were also killed
against the Monument. A special rea-
son is assigned for this. The bats, Of
course, were not all engaged in migra-
ton, but were, for the most part. at
tracted to the fiooded-lighted walls by
the clouds of insects. The insects had
been attracted by the lights and the
bats found the premises to constitute
an excellent feeding ground. Then they
either blindly dashed against the stone
or were blown helplessly by the wind.
Feed BY Day, Fly By Night.
That the birds we're not attracted
by the insects is indicated by the fact
that post -mortem examinations OF the
stomachs of the fallen revealed that
nearly all were empty. The principal
flights, therefore, were of birds employ.
ing the night to move on to their next
station. Apparently most OF these
migrants use the day in which to feed
and the night in which to fly. In con-
trast, the Stomachs of the bats were
filled with the Monument insects.
The average layman would doubtless
find surprise in the great variety OF birds
killed at the Monument by their own
impetuoSity of flight, many OF them
being unfamiliar to any but ornitholo-
gists. Warblers and kinglets and vireoS
were picked up in large numbers and
also song sparrows.
The nature of the injuries of the
birds was also looked into. Some wings
were broken and in some cases the force
of the shock was great enough to break
k.ott, y,,opdihloS 0f the hills There varP