Electric beacons used to frighten wild ducks from grainfields

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United States Department of the Interior.
Fish and Wildlife oe

a heh! a ae oa Wildlife Leaflet 256

Chicage 54, Il. , 3 ee dune 1944

ee ELECTRIC BEACONS USED 70 FRIGHTEN | WILD DUGKS
~ ~~ -FROM GRAINFTELDS ms

By Ralph H. Imler, Biologist, Wildlife Research anenacee
Denver, Colo.

i Bu, */KEWHRODUCSTON

Wild ducks have greatly inerdaged in bombers during the past 10 years ©
and are destroying farm crops in certain localities. Corn and grain sor-
ghums in the Platte River Valley in Colorado and Nebraska, and wheat and
barley in the Dakotas are seriously damaged each fall. Injury to rice in
California, Texas, and elsewhere has also occurred.

Several frightening devices, including guns, scarecrows, flares, lights
revolved by the wind, and different types of pyrotechnics have been used in
attempts to keep wild ducks out of grainfields. All are helpful to some ex-
tent, but a combination of several frightening methods is usually more effec-=
tive than any one alone.

Electric beacons have been used for frightening ducks in Skagit County,
Wash. Robert N. Hart, State Game ‘Jarden of California, devised a rotary
duck beacon ‘that proved: successful in frightening ducks from crops in the
Imperial Valley. This béacon is compact and well built. A clockwork mecha-
nism turns the current on and off intermittently, and while it is on, ae
revolving light throws a steady beam over the field,

The beacon used in the experiments described in this leaflet is similar

to that referred to with the exception that the light flashes continually as ie

it revolves, ‘The flashing light seems to be more effective (nen a BOSS. Bion
beam.

DESCRIPTION OF B¥ACON

An automobile spotlight was used for this exverimental beacon (fig. 1)).
An ordinary headlight is satisfactory if it is equipped with a clear glass

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lens and a 50-candképower bulb; the spotlight is more suitable, however, be-
cause it has a stem that can be used in mounting the light. The beacon should
be so constructed that the beam may be raised or lowered. This adjustment is
necessary to accommodate the beam of light to undulations of the terrain.

The electric current is delivered to the revolving light by means of
two brushes made of spring brass (fig. 1, D). The lower brush connects with
the central post of the spotlight and the upper one with an insulated copper
ring to which has been soldered the spotlight wire leading from the bulb.

It is powered with a 6-volt phonograph motor making 78 revolutions a
minute, and the speed is reduced by a set of V-belt pulleys so that the
beacon revolves three times a minute. By using a different type of moter,
the beacon can be made to operate on a 115-volt alternating current. Low-
speed motors adapted te the 115-volt current are also used in electric pho-
nographs and may be salvaged from such machines, A 6-volt storage battery
will eperate the beacon 20 to 30 hours on one charging. During very cold
weather it may be necessary to bury the battery to prevent its freezing as
the charge runs low,

The flashing light.is produced by connecting in the circuit near the
spotlight a "flasher" ef the type used in automobile tail lights (fig. 1, G),
This causes the beam of light to go on and off about 70 times a minute. The
. frequency lowers to less than 60 times a minute as the battery becomes wea-
ker. A continuous beam can readily be produced by shorting the "flsher" from
the circuit. ;

An ordinary alarm clock equipped to turn off the battery current about
8 minutes out of each quarter hour is illustrated in figure 2. The copper
plate is insulated from the clock by rubber, The beacon operates only when
the current is turned on by the minute hand of the clock making contact with
the inside projections of this copper plate. The original minute hand of the
clock was replaced with a piece of spring brass and the hour hand removed,

The case protecting the motor and other parts of the beacon is weather-=
proofed with a single piece of galvanized. metal, which extends down about 1
inch over each side. A small rim is soldered around the hole through which
the beacon shaft revolves. A "skirt", which is fastened to the shaft, pro-
jects downward over the soldered rim and prevents rain and snow from enter-
ing the case (fig. 1, B), Thus equipped, the beacon operates successfully
in both rain and snow,

The battery will have to recharged every second day if the beacon is
operated continuously each night. If the beacon is used during the evening
and the morning "flight periods" only, the battery will function for a week
on one charging. This would necessitate two additional trins into the field
each night: one to turn the beacon off when the evening duck flight is over