Table of Contents

Introduction

Bird damage is a huge problem in all grape-growing areas of the world. Birds can destroy a crop and farm profits. Most agree the problem is worsening, as more hectares of tasty cultivars are grown (Figure 1).

Damage begins around veraison, when grapes start to colour, signifying change from growth to ripening and the accumulation of sugars. Damage continues through to 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. Although birds prefer blue/red French hybrids and red Vinifera grapes, damage is reported in just about all grape cultivars.

Bird Control Strategies

There are many bird control strategies, including visual, physical and acoustical deterrents. Experts agree a combination of methods is needed. One acoustical option is a propane-fired, bird-scaring cannon — informally known as a bird banger — that emits cannon like sounds (Figure 2). Over 80 countries on six continents 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 bird banger. Today most bird bangers are triple-firing ones that are even more effective. These are operated electronically instead of mechanically.

How Bird Bangers Work

Bird bangers vary in design, but operate under similar principles. They 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; 9 kg (20 lb) tank of propane gas; valves; and control system. When activated, a valve lets propane gas into the barrel, which is then ignited by the spark plug. An explosive-type sound is created, blown out the open end of the barrel (Figure 2 and Figure 3).

Bird bangers have a tripod with one adjustable leg to level it so it spins in all directions. Triple-firing bird bangers produce a series of three shots — the first startles birds, the second (about 8 sec. later) drives them away, and the third (about 10 sec. after the second shot) makes sure birds will not return.

The momentum from the shots causes the barrel to recoil and spin away from the direction of emitted sound. In Figure 3, looking down from above a bird banger, the recoil makes the barrel turn ‘clockwise’. The bird banger will spin up to 10 times over the firing sequence before stopping, awaiting the next sequence. Tests by the author show if properly levelled a bird banger will fire in all directions over time. However, wind speed and direction can affect final pointing direction.

If bird bangers are not set level they will fire more often in one direction than another, and this can be a problem if it happens to face a neighbour's home.

A control system regulates the frequency of each set of three firings to occur randomly. On most bird bangers there is one set of three firings every two to four, four to eight, eight to 16 or 16 to 32 minutes. Randomness helps keep birds wondering when the next firings will occur and prevents them from growing accustomed to the sound. Field tests by the author show firing sequences are random within the setting. So, on the four to eight minute frequency setting, expect sequences to average about every six minutes.

Best Management Practices for Vineyards

Here are best management practices (BMP) for bird bangers used to scare birds from vineyards, taking account of the needs of both growers and neighbours.

Normal Farm Practice and the FFPPA

Some neighbours do not like the sound from bird bangers — especially when the cannon is operated by vineyard managers who do not live in the area to hear when a bird banger is not working properly. Most Ontario grapes are grown near many rural neighbours, since many people like to live near vineyards/wineries. Neighbours need to be tolerant to growers for the need for bird bangers to grow grapes, but likewise growers need to be tolerant to neighbours for the need for quiet times.

As long as they follow normal farm practice, farmers are protected from nuisance noise complaints launched by neighbours. The Farming and Food Production Protection Act (FFPPA) 1998 defines normal farm practice as one which:

Whether or not a farm practice is considered normal is determined by the Normal Farm Practices Protection Board, a quasi-judicial administrative board appointed by the provincial government, but comprised of non-government members. For information see www.omafra.gov.on.ca/english/engineer/nfppb/nfppb.htm

Practices that are Not Normal

It is frustrating for a neighbour when a bird banger is not operating within normal farm practice. Grape growers agree the following rules should apply:

BMP Setbacks for Bird Bangers

Grape growers need the small area of farmland where conditions are favourable for growing grapes. Neighbours need peace and quiet, but have more options about living locations than growers about where to grow grapes. So, compromise is needed.

It is impractical to create setbacks based on the site-specific measured sound levels in dBA from each individual bird banger. This is because even though the emitted sound level is the same as it leaves the barrel of the bird banger, it varies greatly after release depending on localized weather conditions, wind speed and direction, topography, ground cover, direction of firing, etc. So, the current BMP setback from neighbours for normal operation of a bird banger is set to125 m (410 ft) when the bird banger is operated:

The 125 m (410 ft) setback has evolved and worked well for grape growers and neighbours, but other setbacks also make sense if practices are used that increase sound levels (with greater setbacks), or decrease sound levels (with lesser setbacks).

Field tests by the author explored more flexible setbacks. The 125 m setback was used as a benchmark under the four management options listed previously. It was determined sound levels, and resulting annoyance for neighbours are:

There are 2 x 2 x 2 x 2 = 16 combinations. Each results in setbacks based on sound levels that are effectively increased, or reduced, giving flexibility for different vineyard situations and conditions. Figure 7 demonstrates how each combination affects best management practices setbacks for bird bangers from neighbouring homes.

A grower with ice-wine grapes fires a bird banger in all directions on the ‘B, loud volume’ setting, with Frequency 2 (4–8 min.) firing sequence. Using Figure 7, what setback is recommended to houses?

Enter Figure 7 from centre, moving through layers: Ice-Wine Harvest; 360° (meaning bird banger fires in all directions); B-Loud; and F2 (4–8 min.) to a 175 m setback.

To reduce the setback to 125 m, one could set the bird banger on A-Quiet or restrict it to fire only in the 180° plane away from a neighbouring home.

References

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.

This Factsheet was written by Hugh Fraser, Engineer , Hort Crop, Protection & Post Harvest, OMAFRA, Vineland. It was reviewed by Ian Frensch, P.Eng., C.Frensch Ltd., Beamsville and William George, Chair, Grape Growers of Ontario.