A Charles Sturt University (CSU) researcher has shown that the benefits of birds far outweigh their costs to agricultural production in much of Australia.
CSU ecologist Dr Rebecca 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.
Aim: To examine cost-benefit trade-offs of bird activity in apple orchards, pastoral systems, and vineyards in south-eastern Australia
Location(s): Farmland (apple orchards, vineyards, and grazing lands) in central and northern Victoria and southern New South Wales.
The research: Field studies conducted on commercial 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.
Supervisors: Professor Gary Luck and Dr Manu Saunders
- 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 - see left) reduced the weight of dead rabbits by on a pastoral grazing station by up to 100 per cent, disposing of rotting carcases, reducing the spread of disease and preventing the arrival of foxes.
- Providing artificial perches for predatory and territorially aggressive birds such as the Australian magpie scares grape-eating birds such as common starlings (Sturnus vulgaris) and European blackbirds (Turdus merula) from vineyards, reducing average bunch damage from nine to four per cent.
- The landscape surrounding a farm influences the activity of birds within the farm. The amount of nearby native vegetation is important for regulating ecological communities and ecosystem function within a crop.
- 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.
Listen to Dr Peisley
Dr Peisley said, “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.
“With growing global demands, the future of food production relies on minimizing negative environmental impacts and maximizing 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.”