Using Propane-Fired Cannons to Keep Birds Away From Vineyards
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Bird damage is a problem in all grape-growing areas of the world. Most agree the problem is worsening as more hectares of cultivars are grown. Damage begins around veraison when grapes start to colour, signifying change from growth to ripening and the accumulation of sugars. Damage continues until harvest in early fall or winter with grapes harvested for ice-wine. A field trial (Fraser, 2005) showed with no bird controls, losses were 50 per cent for Cabernet Franc and 100 per cent for Cabernet Sauvignon by late October. Although birds prefer blue/red French hybrids and red Vinifera grapes damage is reported in all cultivars.
There are many bird control strategies: visual (streamers, balloons, lights, fake hawks); physical (nets), and acoustical deterrents (electronic sound devices, pyrotechnic pistols). Experts agree a combination of methods is required.
One acoustical option is a propane-fired, bird-scaring cannon also known as a bird banger that emits cannon like sounds (Figure 1). Over 80 countries use bird bangers to control crop damage (Frensch, 2008). A five year Manitoba study concluded bird bangers were very effective for scaring birds away from field corn and sunflowers. Double-firing bird bangers were found to protect more than twice the area of a single-firing one. Today most bird bangers are triple-firing ones that are even more effective.
Some neighbours do not like the sound from bird bangers. Paradoxically, grapes are grown near many neighbours since people like living near vineyards. Neighbours need to be tolerant of growers who use bird bangers as there is only a small area of Ontario with favourablegrowing conditions. Likewise, growers need to be tolerant of neighbours' needs.
This Factsheet outlines best management practices (BMP) for bird bangers. It is written for grape growers, neighbours, municipal by-law officers, members of the Normal Farm Practices Protection Board under the Farming and Food Production Protection Act (FFPPA) 1998 and government agencies dealing with nuisance noise issues.
Figure 1. This side view of a bird banger shows the cylindrical barrel at top, open on one end (right side in photo), control system box (top, back), tripod and tank of propane gas.
If they follow normal farm practice farmers are protected from nuisance noise complaints by neighbours in accordance with the Farming and Food Production Protection Act (FFPPA) 1998. The legislation defines normal farm practice as one which:
Normal farm practice is determined by the Normal Farm Practices Protection Board, which is a quasi-judicial administrative board appointed by the provincial government but comprised of non-government members. For information see Normal Farm Practices.
The principle for best management practices for bird bangers is that their only use is to protect bearing, marketable grapes from bird predation. The number of bird bangers operated should be appropriate for the amount of bird pressure present. Malicious use for any other purpose must not be tolerated.
Figure 2. Ring-graph used to determine bird banger setbacks to neighbours based on management strategies.
It is impractical to create setbacks based on site-specific measured sound levels in decibels (dBA) from every bird banger. The emitted sound levelis the same as it leaves the barrel of a bird banger, but it varies greatly after release depending on localized weather conditions, wind speed and direction, topography, ground cover, direction of firing, obstructions like buildings, etc.
Under most circumstances, the BMP setback is 125 m (410 ft) from neighbours for normal operation of a bird banger when it is operated:
The 125 m (410 ft) setback is based upon field sound level measurements at varying distances from a bird banger and under different bird banger settings. Other setbacks also make sense if practices are used that increase sound levels (requiring greater setbacks), or decrease sound levels (requiring lesser setbacks).
Field tests by the authorexplored setbacks based on different settings than those outlined above (Figure 2). Sound levels and annoyance for neighbours are:
Figure 3. '1' = Frequency 1 (24 min.); '2' = Frequency 2 (48 min.)'3' = Frequency 3 (816 min.) '4' = Frequency 4 (1632 min.) 'A' is quiet volume sound setting; 'B' is loud volume setting.
A grower with ice-wine grapes fires a bird banger in all directions on 'Bloud volume' setting, with Frequency 2 (48 min.) firing sequence. Using Figure 2, what setback is recommended to neighbours' homes?
Bird bangers have a cylindrical barrel about 100 mm (4 in.) in diameter and 0.8 m (32 in.) in length open at one end, a spark plug, a 9 kg (20 lb) tank of propane gas, valves and a control system. When activated, a valve lets propane gas into the barrel that is ignited by the spark plug. An explosive sound is created, blown out the barrel's open end.
To spin uniformly in all directions, most bird bangers
are mounted on a tripod with one adjustableleg to level it. Triple-firing bird
bangers produce a series of three shots over about 17 seconds the
first startles birds, the second drives them away, and the third makes sure they
will not return.The momentum from the shots causes the barrel to recoil and spin
away from the direction of emitted sound (Figure 4).
Tests by the author show if properly levelled, a bird banger will fire in all directions over time, although wind speed and direction can affect final pointing direction. If bird bangers are not level they will fire more often in one direction than another, and this is a problem if it is at a neighbour's home. The frequency of random firing can be adjusted to one set of 3 firings every 2 to 4, 4 to 8, 8 to 16 or 16 to 32 min. (Figure 3). On the 4 to 8 minute frequency setting, expect sequences to average about every six minutes. Randomness keeps birds wondering when the next firings will occur and prevents them from growing accustomed to them. Figure 5 shows how to set the timer mechanism in the control system box.
Figure 4. This overhead view shows as sound waves exit a bird banger barrel it causes recoil, turning it clockwise. Tests show it can spin up to 10 times before stopping.
Figure 5. Inside a bird banger control system box, an operator can adjust when a bird banger starts in the morning and stops in the evening. The setting shown is appropriate for September 26 at Harrow as per Table 1.
Fraser, H.W. 2005. Presentation at Ontario Fruit and Vegetable Conference, February 2005.
Frensch, I. 2008. Personal Communication, July 22.
Harris, H.A.G. 1983. Blackbird Predation on Field Crops in Southern Manitoba. Summary from Annual progress report on the AGRO-MAN (Central Plains Special Crops Protection Association) Blackbird Control Project.
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