Noisy Miner - Distribution and Habitat

Distribution and Habitat

The Noisy Miner is endemic to eastern and south-eastern Australia, occupying a broad arc from Far North Queensland where there are scattered populations, to New South Wales where it is widespread and common from the coast to a line from Angledool to Balranald, through Victoria into south-eastern South Australia, and eastern Tasmania. Its range in South Australia has been steadily expanding since it was first recorded near Adelaide in the early 1890s. It is sedentary over its entire range. The Noisy Miner is territorial, and the territory of a colony is aggressively defended—which has led to a significant reduction in avian diversity in areas occupied by the Noisy Miner, with smaller species excluded.

The Noisy Miner primarily inhabits dry, open eucalypt forests without understory shrubs. It is commonly found in open sclerophyll forests, including those on coastal dunes or granite outcrops; forests dominated by spotted gum on mountain ridges and exposed slopes; box and ironbark forests on the foothills of the Great Dividing Range; mixed forests of eucalypts and cypress (Callitris); forests dominated by yapunya, mulga, gidgee, brigalow or emu bush; in stands of belah and scattered clumps of boree; on the edges of woodlands of river red gum including swamp woodlands bordering floodplains, and areas dominated by exotic species such as European ash and willow. It regularly inhabits degraded patches of forest where the understory has been cleared, including recently burned areas, and modified habitats such as lightly-timbered farming and grazing areas, roadside reserves, bushland remnants in towns and cities, and suburban parks and gardens with trees and grass but without dense shrubbery.

The Noisy Miner has benefited from the thinning of woodland on rural properties, heavy grazing that removes the understory, fragmentation of woodland that increases the percentage of edge habitat, and urban landscaping practices that increase open eucalypt environments. It has been described as a ‘reverse keystone’ species, as it is colonizing an ever-increasing range of human-dominated habitats, and aggressively excluding smaller bird species from urban environments. This phenomenon has been also observed in rural areas. A field study across the South West Slopes of New South Wales, showed that the Noisy Miner's presence corresponded with reduced numbers of insectivorous birds such as fantails, whistlers, the Restless Flycatcher (Myiagra inquieta), and other honeyeater species, and that this decrease was most marked in sites with better access to water and nutrients. While it has been hypothesized that the proliferation of large-flowering grevillea cultivars has contributed to the abundance of Noisy Miners, recent research has identified the proliferation of lightly treed open areas, and the presence of eucalypt species as the most significant factors in the population increase. Large-flowered grevillea hybrids such as Grevillea 'Robyn Gordon' can benefit the Noisy Miner, in that an abundance of resources is usually dominated by larger aggressive honeyeaters, and a continuous nectar source could provide an advantage for the non-migratory species. A field study in box-ironbark country in central Victoria found miner numbers were correlated with the occurrence of yellow gum (Eucalyptus leucoxylon), which reliably produces flowers (and nectar) each year. However, the abundance of the Noisy Miner is primarily determined by habitat structure.

While the range of the Noisy Miner has not significantly expanded, the density of the population within that range has substantially increased. High densities of Noisy Miners are regularly recorded in forests with thick understory in southern Queensland, 20 kilometres (12 mi) or more from the forest/agricultural land edge. Many of these sites have extensive road networks used for forest management, and picnic areas and walking tracks for recreational use, and it has been found that these cleared spaces play a role in the abundance of Noisy Miners in the forests. There is evidence to suggest that higher road densities correspond with higher Noisy Miner population levels. Field work in Victoria showed Noisy Miners infiltrated anywhere from 150 to 300 m (490 to 980 ft) into remnant woodland from the edges, with greater penetration occurring in less densely forested areas. This has implications for the size of woodland habitat needed to contain miner-free areas—around 36 hectares (89 acres). Revegetation projects restoring buloke woodland, a species of she-oak integral to the survival of the Red-tailed Black Cockatoo (Calyptorynchus banksii), have been interplanted with a nurse species, usually fast-growing Eucalypts. Noisy Miner populations were more likely in those buloke woodlands where Eucalypts had been planted at densities of up to 16 per hectare (6.4 per acre). The presence of Noisy Miners was accompanied by a substantial difference in number and types of other birds found in the woodland.