Birds on Farms
The conservation and scientific value of the New Atlas of Australian Birds is considerable and has a range of applications. The results of the Atlas will be of particular use to farmers and landholders around Australia who have adopted the principles of sustainable agriculture.
Protecting natural ecosystems and maintaining biodiversity are key elements of sustainable agriculture. A number of studies have shown that the areas with healthy bird populations will be those where the other elements of biodiversity, such as vegetation, mammals, reptiles and insects, will be thriving. As 'indicator species', the presence of birds gives an indication of the ecological health of the farm.
In addition, birds play a critical role in maintaining tree health, which provide shelter for stock and windbreaks. A major cause of eucalypt dieback on farms in eastern Australia is insect attack, yet a healthy bird community removes up to 70 per cent of leaf-feeding insects from farm trees and helps sustain those trees.
Birds Australia commenced an extensive survey in 1995 to assess whether the environmental work undertaken through organisations such as Landcare was attracting birds back into rural landscapes. Thanks to funding from the Commonwealth Government's Natural Heritage Trust, the Thyne Reid Education Trust and the Norman Wettenhall Foundation, the Birds on Farms survey recorded 430 bird species over two years on 330 farms in southern and eastern Australia. Around 500 volunteers were involved in the survey, 76 per cent of whom were either farmers or people working with farmers.
Involvement in the Birds on Farms survey increased participants' awareness of rural conservation issues and in 20 per cent of cases, this led to changed management practices. Many of the Birds on Farms volunteers went on to become involved in the survey activities for the New Atlas of Australian Birds.
The Birds on Farms survey has led to the development of 10 simple guidelines for attracting birds back to farms, and so improving the natural resource base on which agriculture depends:
- Local native vegetation should cover at least 30 per cent of the total farm area
Research indicated that such a measure was necessary to keep farms healthy, halt problems such as salinity and soil deterioration, and maintain optimum long-term productivity.
- Re-create local conditions
Look to the trees, shrubs and herbs in patches of remnant scrub and along roadsides to find out what the original vegetation was like. For example woodland birds such as the Rufous Whistler and Grey Fantail were 8 per cent more diverse on farm sites where at least two different tree species were present.
- Exclude high-impact land uses from at least 30 per cent of the farm area
While suitable management practices will be dependant on the location of the farm, land uses that have a high impact on native vegetation, such as cropping, fertilizer application or frequent grazing, should be excluded. For example moderate to light grazing levels and native pastures favour native pigeons such as the Common Bronzewing.
- Maintain native pastures and avoid heavy grazing
More than half of the declining bird species in temperate Australia forage at least partly on the ground and depend to some extent upon native pastures. By maintaining a range of grazing regimes across farms and avoiding heavy, continuous grazing, pasture and understorey diversity will be greater and bird diversity enhanced.
- Native vegetation cover should be in patches of at least 10ha and linked by strips at least 50 m wide
While the 30 per cent of the farm that is managed to protect native vegetation is best as a single large patch, landholders are more likely to want the vegetation cover spread across the property as windbreaks. A compromise is to spread the vegetation across the farm, but make the patches as large as possible and linked by native vegetation.
- Manage at least 10 per cent of the farm area for wildlife, i.e. creating as much habitat diversity as possible
Of the 30 per cent of the farm area that is local native vegetation, one-third should be managed primarily for wildlife. As a general rule, the more complex and diverse the habitat the more bird species and other wildlife will be present.
- Maintain a range of tree ages
Bird diversity has been found to increase by 30 per cent for every 10 large trees present at a farm site. Large, old trees produce bark and leaves through which birds will forage for food, and when they flower, will draw birds from many kilometres away. For example one in five Australian birds require nest hollows for breeding, including the Laughing Kookaburra and the Barn Owl.
- Leave fallen trees to break down naturally
Fallen trees encourage shrubs to regenerate and leaf litter to build up, creating habitat for ground and bark foraging birds. For example for every 10 fallen trees present at a farm site, the diversity of ground-foraging birds increased by 30 per cent and bark-foraging birds by 70 per cent. As an added benefit to farmers, when positioned as windbreaks away from the property, native trees, shrubs and fallen trees can slow the progress of fires.
- Maintain shrub cover over at least one-third of the area within a patch of farm trees
Trees and shrubs shelter crops and stock against environmental extremes and provide understorey birds with protected nesting sites. Plant a diversity of locally occurring shrub species, but avoid planting too many nectar-producing shrubs as this may attract large, aggressive honeyeaters such as Noisy Miners. In farm sites where understorey shrubs were present, there was a 24 per cent increase in small woodland-dependant foliage gleaners - birds that help control the spread of eucalypt dieback.
- Maintain native vegetation around water
With the addition of features such as dense shrubby vegetation, shallow areas for birds to feed, islands or dead trees for birds to roost, or fencing around farm dams and waterways to exclude livestock, there was a 14 per cent increase in water bird diversity. For example small birds were 28 per cent more diverse and ground-nesters were 29 per cent more diverse when waterways were present.
For a small fee, the Birds on Farms brochure is available from Birds Australia on (03) 9882-2622 or you can check out the interactive web program, Remnants, which can help diagnose the general health of a farm and give suggestions for improving bird diversity. Remnants can be found on the Birds Australia web site at: www.birdsaustralia.com.au/remnants .