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Group Title: Mimeo report - University of Florida Everglades Experiment Station ; 54- 3
Title: Instructions for the use of firecrackers to protect corn from blackbirds in the Florida Everglades area
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00067590/00001
 Material Information
Title: Instructions for the use of firecrackers to protect corn from blackbirds in the Florida Everglades area
Series Title: Everglades Station Mimeo Report
Physical Description: 5 leaves : ; 29 cm.
Language: English
Creator: Mitchell, Robert T
Everglades Experiment Station
Publisher: Everglades Experiment Station
Place of Publication: Belle Glade Fla
Publication Date: 1954
Subject: Corn -- Diseases and pests -- Florida   ( lcsh )
Bird pests -- Florida   ( lcsh )
Genre: non-fiction   ( marcgt )
Summary: "This report is based on research conducted by U.S. Fish and Wildlife Service and includes tests made near Belle Glade in cooperation with Florida Agricultural Experiment Station."
Statement of Responsibility: Robert T. Mitchell.
General Note: "May 1, 1954."
General Note: Cover title.
 Record Information
Bibliographic ID: UF00067590
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 65519375

Table of Contents
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        Front Cover
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Full Text

*U'o 14 19955



Rdbert T. Mitchell

*e-* 5- -* *- ** S t w' *

This report is based on research conducted by U.S.
Fish and Wildlife Service and includes tests made
near Belle Glade in cooperation with Florida Agri-
cultural Experiment Station.


Belle Glade, Florida

May 1, 1954

l- 3

5 -i,,

Instructions for the Use of Firecrackers to Protect Corn from
Blackbirds in the Florida Everglades Area

Robert T. Mitchell
U. S. Fish and Wildlife Service
Laurel, Maryland

Investigations conducted by personnel of the U. S. Fish & Wildlife Service
on blackbird depredation to rice in Arkansas and to corn in Delaware and New Jersey
show that the best method of protecting the ripening grain of these crops is through
the use of the .22 rifle. From an elevated structure within or along the edge of t1h-
field one man with a rifle can protect an area of well over 100 acres. The elevate?.'
not only allows him to see where birds are settling and therefore where the cartridge
should be aimed but also makes shooting safer by increasing the angle of the bullet
to the ground. It is nevertheless a dangerous operation and growers in the Ever-
glades area are, for the most part, rightfully reluctant to use the rifle in fear
of injuring farm laborers or livestock in neighboring fields,

The next most effective and economical scare device known is the rope-
firecracker assembly which consists of sections of cotton plowline along vhich
firecrackers are arranged at various intervals. The fuses are inserted between the
rope strands and sections of this assembly are suspended to supports throughout the
field. Corn stalks that are sufficiently tall may serve as satisfactory supports.
These rope-firecrackers operate by being lit at the free-hanging end; and as the
rope slowly burns toward the fastened end, the fuse of each successive firecracker
is ignited, and the firecracker drops to the ground where it explodes with a loud
report. Excellent results have been obtained from using a set of rope-firecrackers
every 360 feet.

Several styles of firecrackers are acceptable. Some of those that have
been tried are cherry bombs, cannon crackers and bull dogs. Of these three, bull
dogs are the least expensive and the difference in intensity of their explosions
is not great enough to warrant buying the more expensive ones.

In acquiring a satisfactory rope it is important to consider several
necessary features. It should be 3- or 4-strand cotton rope 5/16" to 3/8" in diame-
ter. Rope of this thickness burns at a reasonable speed, one inch in 6 to 11 minute
depending upon the amount of wind and other atmospheric conditions. The greater the
diameter of the rope the slower it burns. The strands should be readily separable
for easy insertion of firecracker fuses. Ropes that are so tightly twisted that the
strands must be pried open for firecracker insertion often spring apart as the rope
burns back, releasing the firecracker before its fuse becomes ignited.

In making up a rope-firecracker, measure the desired length and tie a
piede of twine above and below where the rope is to be cut. This will keep the
rope from unwinding after being cut. If the rope is meant to be lighted in the
early morning hours, a dozen or so firecrackers can be spaced close together, say
at 1 to 1 1/2 inch intervals, along the first foot and a half of rope and then
a second dozen progressively farther apart along the remaining length. Thus, more
frequent explosions will occur when the birds are most active in the field. Many
firecracker ropes can be made in advance using the same firecracker sequence but
the rope that is to be burned during the afternoon period is suspended by the oppo-
site end so that more frequent explosions occur during the last hours of daylights
In order to save labor, some operators made up each rope to last the entire daylight
period. Sometimes, on especially still days, the ropes did not burn as rapidly a~
anticipated and the firecrackers would then be exploding after dark, or on windy dayz
they would completely burn out before the birds had gone to roost. To avoid such

situations, it is considered advisable to set out ropes for only one-half day's
operation and to inspect installed operating ropes by midday. Adjustments can
then be made in accordance with requirements of prevailing weather conditions.

The easiest procedure in using rope-firecrackers is to tie one end of the
rope to a cornstalk and allow the firecrackers to drop to the ground to explodes
Protection over a much larger area is obtained, however, if the rope-firecrackers
are hoisted to the top of a 15 to 20-foot pole from which the firecrackers will
drop into a strong wire basket farther down the pole but still above the height of
the corn. In this manner, the sound is not absorbed by the ground or the standing
corn. One grower using such an arrangement claimed that one rope will protect an
area of at least 10 acres (660' x 660),

The rope-firecrackers can often withstand light drizzles without loss of
effectiveness, except that they burn more slowly; but they need protection on rainy
days and in heavy showers. To avoid water damage the rope can be lightly stapled
at various places within an inverted wooden apple crate on a pole, or a canvas
shelter can be arranged above it.

To reduce costs in operating rope-firecrackers, the farmer should make
frequent checks on bird activity in his field. He may discover that he is using
more firecrackers than necessary, or he may find that by setting the ropes in
different places he may get better results for the same expenditure. The automatic
feature of a rope-firecracker operation plus the fact that the position of the fir.-
crackers on the rope are adjustable to suit the needs of the farmer's particular
field problem are outstanding advantages of this type of control device.

There are several advantages of rope-firecracker operations over the use
of the shotgun. Labor costs are lower; also the farmhand or grower is free for most
of the day to perform other tasks. Even though there may be explosions from the
rope-firecrackers when they are seemingly unnecessary, four bulldog salutes, each
producing a louder blast than a shotgun shell, are obtainable for the price of one
shell. Furthermore, this investigator has observed that farmhands often shoot
needless quantities of shells. Some of them are also inclined to kill birds other
than blackbirds. Robins, sparrows, warblers, and even an egret, none of which are
guilty of causing corn damage were observed to have become victims of "blackbird
shooters" in the Everglades area this season. A considerable amount of money could
be saved, illegal shooting eliminated, and better results obtained by replacing
shotguns with short pieces of burning rope, which the operator could carry from
which to light firecrackers separately. With a little practice the operator can
soon learn how long to hold the firecracker in his hand before giving it a toss
and have it explode in the air above the height of the corn where the explosion
would be most effective.

The economy and superior results of firecracker operations over shotgun
shooting was demonstrated in a sweet corn field near Pahokee. This 21-acre field
(l100 x 665') was easily accessible from a hard surfaced road, and when divided
across its width, formed two almost square halves. For these reasons it was con-
sidered a desirable field in which to try for the first time a limited supply of
2-shots, a newly designed firecracker described in detail later in this paper.
Since the capability of the 2-shots was unknown, four ropes of bull dogs, which
alone would have provided ample protection, were operated in one half of the field
in conjunction with the 2-shots. The 2-shots were placed in the center of the 10 1/2
acre section and the four sets of bull dogs were placed 170' x 1751 within the
field from each corner. No bird damage to the corn was seen in a random sample
of 1500 ears throughout the entire field on March 15, when firecracker operations
were commenced. The crop was harvested on March 18, and during that time 112 2-shots,
651 bull dogs, and 88 feet of rope were used, and the investigator had spent abou'-.
12 hours on the operations. The total cost, considering labor at 65 cents per hour,
amounted to $O0.50, or about 03.85 per acre.

Damage surveys were made just ahead of the harvesters, the samples being
taken along the rows midway between firecracker stations. Three damaged ears (0.2
percent) were found in the sample of 1396 ears in the firecracker-protected half of
the field while 28 damaged ears (2 percent) were found in the sample of 1448 ears
in the shotgun-protected half. It must be admitted that far less shotgun shooting
was done in this instance than is customary. In fact, the accumulative shooting
done in that section amounted to no more than 1 day's labor and two boxes of shells
at a cost of about 10. On the other hand, the efficiency of the 2-shots was
greatly underestimated as determined by later experimentation with them. They un-
doubtedly protected an appreciable amount of the other half of the field. Finding
most all of the damaged ears within the fartherest 200 feet or so of the shotgun-
protected half supplies good evidence to this fact. The amount of damage that
would have occurred under more active shooting is, of course, unknown, but the cost
of the firecracker operation exceeded the cost of 4 full days of labor by only $16,
which is the price of less than 8 boxes of shells.

During the fall of 1953 an aerial bomb type firecracker called 2-shots was designed
for use in fields for bird protection. This consists of two upright firecrackers
hitched together with a fast fuse, mounted on a wooden block, and treated with
paraffin for water repellancy. A series of these can be threaded through the slow-
burning rope, like the bull dogs. The rope remains in a horizontal rather than a
vertical position in this case, however. As the firecrackers become ignited a small
bomb is blown into the air where it explodes i th a great intensity. This is followed
in five or six seconds by an equally loud blast in the air from the second firecracker.

Early in April tests with the 2 shots were conducted in a field of Golden
Security sweet corn near Belle Glade in an effort to determine over how large an area
this type is effective against the blackbirds. So complete was the protection pro-
vided that no damage whatsoever was found to mature ears in the more than 6,000-ear
sample taken on the day that harvest was begun. Damage to tassel ears therefore had
to be considered as the basis for determining the distance that one rope-firecracker
set of this type gave protection. This was found to be between 20 and 30 acres
square (933' 1143'). In a plit of Gold Rush, being harvested on the same day, and
less than 2,000 feet away, 3 percent of the ears were damaged by birds. This field
had been protected by airplane buzzing. About 3,000 feet away another Gold Rush Field,
which was sampled for damage at harvest time two d4ys previously, was found to have 2
percent of the ears damaged. This second field had been protected by both shotgun
and airplane.

An approximation of expenses involved in operating one of the 2-shot fire-
cradker ropes for five days prior to harvest is as follows:
3 3/4 hours of labor @ $.65 $ 2.45
200 2-shots @ .16 32.00
30 ft. cotton plowline @ .02 .60

Assuming a coverage of 20 acres, the cost of protecting one acre with 2-shots amounted
to about $1.7$.

If one man with a shotgun were employed to protect an equal area, which he
undoubtedly could not adequately cover, for five days, the labor costs alone would
amount to more than $30, and in that period he would shoot less than two boxes of
shells before the cost of protecting the area with 2-shots would be exceeded.

For operating the 2-shot firecrackers a special detonating rack was con-
structed. This wooden rack was four feet long with a trough into which the series
of 2-shots on the 4-inch blocks were placed. A second smaller trough ran along the
edge of the rack where the rope fuse was arranged, Although the 2-shots were waxed,
extra protection, consisting of removable roofs of galvanized tin were constructed
to cover the fuses in rainy weather.

Since the wooden block bases are 1 1/2 inches wide, the 2-shots could not
be spaced at intervals on the rope shorter than that. On still mornings explosions
would therefore occur only once in 15 minutes, which is inadequate for early morn-
ing operations. An additional double rack was therefore made with a trough for the
2-shots located on both sides of the fuse trough. This rack was 7 inches long and
accomodated four 2-shots on each side of the rope. By using this additional rack
12 sets of explosions were obtained within the first hour of operations. Sixteen
sets were used in the morning on the four foot rack. The four foot section of rope
on it had usually completely burned shortly after 2 P.M. At this time lengths of
rope gauged to burn until about 6:15 P.M. were cut for both racks. Seven 2@shots
were then added to the new rope on the 4-foot rack, four of them at the very end
of the rope. Eight of them were put on the double 7-inch rack, which, of course,
had quite a long lead of rope without firecrackers since the eight 2-shots on this
rack were not intended to function until about 5 P.M.

The 2-shots show such promise of becoming a very effective and economical
scare device that additional tests will be made with them this year. Through
further investigations and more extensive use of them, simpler methods of using them
will undoubtedly develop and production costs can be reduced. *

Sprouting corn can likewise be protected with firecrackers. No experiments
have been conducted to determine over what distance the sound of the bull-dog type is
effective under these conditions, but it would probably carry more than twice as far
as in mature corn. If this is so, it might not be economical to use the more ex-
pensive 2-shots in this situation. Under normal growing conditions corn sprouts are
vulnerable to being pulled by birds for about five days.

IN THE CROP (i.e., before they become accustomed to coming to the field to feed)
ARE BEGINNING TO ARRIVE FROM THE NIGHT ROOST. It is usually an easy matter to drive
the birds some distance during this early morning flight period. Once they are
allowed to settle down for any length of time, however, they are inclined to stay
in that vicinity for the remainder of the day.

The arrival and departure time of the birds to and from the field varies
from field to field, from day to day, and from season to season. The closer the corn
field is to the roost, which in the Everglades area is usually a mature sugar cane
field, the earlier the birds will arrive in the morning and the later they will stay
in the evening. On a cloudy or foggy morning their flight to feeding grounds will be
delayed somewhat, and late afternoon storms or cloudiness will cause them to return
to roosts earlier. On rainy days they are inclined not to venture so far from the
roost, so a field closeby will be especially vulnerable under those conditions. As
the hours of daylight increase from winter to summer, birds enter the fields earlier
and stay later. There are, however, bird-free periods at both ends of the day4
Thus, if the rope-firecrackers are lit as soon as it is sufficiently light to see,
they will be operating by the time the birds arrive. Neither is thee a need for
having them burn until dark. Each field is therefore an individual problem, and
the fact that rope-firecrackers are readily adaptable in respect to length of time
they can be operated and the frequency of explosions obtainable makes them capable
of meeting the special requirements of any area being protected.

Information on the source of firecrackers can be obtained from the Palm
Beach County Agricultural Agent's office or from the Everglades Experiment Station,
where there are also on hand samples of the detonating racks herein described.

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