BIRD DAMAGE
Identification
- Total removal of berries
- Angular punctures in berries
- Bird damage is usually localized and not uniformly distributed throughout an area
Often Confused With
Hail damage – follows severe weather and can occur throughout the growing season, not just after veraison; more severe on one side of the row than the other: leaves tattered with holes in them
Mechanical damage from leaf removal or other vineyard operations – follows vineyard operations and can occur throughout the growing season, not just after veraison
Biology
Robins and starlings cause the most injury.
- Starlings will fly 25 km from a roosting site to feed, flying at up to 70 km/hr in short bursts.
- Bird damage patterns can vary considerably from year to year and from farm to farm.
- It is difficult to break birds of the habit of feeding in a particular area once they are established.
- Vineyards near roosting or nesting areas, woodlots or ponds are more vulnerable than those in the open.
- Birds acclimate quickly to uniform movements or noise patterns.
- Birds often follow the same flight patterns to feed.
- Some birds travel in migratory flocks, while others fly in from local woods.
- Birds feeding on your crop will attract other birds, compounding the problem.
- The sweeter and earlier the grape cultivar, the more attractive it is to the birds.
- Bird damage is more severe in dry seasons.
- Even if crops are protected with netting, birds may perch on the nets and feed through them or find or create small holes.
Period of Activity
After the onset of veraison. Birds usually feed early in the morning around sunrise and late in the afternoon around sunset.
Scouting Notes
Injury will first be noticeable in earliest maturing cultivars, especially on exposed clusters.
Management Notes
Start bird management early before birds establish a pattern of feeding in the vineyard.
Use a variety of repellent or exclusion methods.
Communicate your plans with nearby neighbours to mitigate disputes about noise.
Vary timing and placement of acoustical devices for best results.
Physical exclusion of birds with nets is the most successful method.
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