BIRDS are the scourge of many fruit crops.
That’s not entirely true according to Charles Sturt University (CSU) researcher and ecologist, Dr Rebecca Peisley, who has shown the benefits of birds far outweigh their costs to agricultural production.
Dr Peisley found birds provide important services to Australian agriculture, particularly to grape growing, apple orchards and extensive livestock grazing.
“When they forage for food, some birds provide positive services by controlling pest insects or removing wastes, while others can be negative by damaging crops,” Dr Peisley said.
“I assessed the positives and negatives at the same time in agricultural systems to find the overall value of birds to that system, something that has never been done before on this scale.”
Dr Peisley’s studies also filled a gap for Australian agriculture, as most research into bird damage and benefits had previously been carried out in the Americas, with very little in Australia.
Commercial apple orchards, vineyards and grazing areas in central and northern Victoria and southern New South Wales were used to explore the topic.
Her field studies conducted on farms over crop growing seasons in 2014, 2015 and 2016.
The studies measured positive bird activity such as insect control, predation of small fruit-eating birds, and waste removal, and negative bird activity such as fruit damage in each system.
She found birds provide a net benefit to apple orchard growers by increasing annual yields by nearly 11 per cent.
The net benefit increased where more suitable habitat for insectivorous birds that eat insect pests were provided next to orchards.
Native raptors such as whistling kites (Haliastur sphenurus), wedge-tailed eagles (Aquila audax) and little eagles (Hieraaetus morphnoides) reduced the weight of dead rabbits on a pastoral grazing station by up to 100PC, disposing of rotting carcasses, reducing the spread of disease and preventing the arrival of foxes.
The research discovered that providing artificial perches for predatory and territorially aggressive birds such as the Australian magpie, scared grape-eating birds such as common starlings (Sturnus vulgaris) and European blackbirds (Turdus merula) from vineyards, reducing average bunch damage from 9-4pc.
The landscape surrounding a farm influenced the activity of birds within the farm.
The amount of nearby native vegetation was important for regulating ecological communities and ecosystem function within a crop.
Dr Peisley found that in apple orchards and vineyards, damage to crops was reduced when sites were close to native vegetation, and scavenging raptors preferred open paddocks that contained large paddock trees.
“Agriculture is the major land-use in Australia, covering more than half of the continent and contributing AU$155 billion to the nation’s economy each year,” Dr Peisley said.
“With growing global demands, the future of food production relies on minimising negative environmental impacts and maximising the ecosystem services that nature, including birds, provides to agriculture.
“Agricultural pursuits can also help conserve many bird species. Providing suitable habitat for ecosystem service species [such as artificial perches in vineyards] is vital for tipping the cost-benefit trade-off in the favour of growers.
“This research is just the beginning for developing sustainable agriculture. Birds are among many fauna that use farmland and contribute to ecosystem function, and each species need to be considered.”