|Issue Date||Spring 2006|
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|Title||Understorey to Keep Noisy Miners at Bay|
Hastings, R.A. and Beattie, A.J. (2006) - Stop the bullying in the corridors: Can including shrubs make your revegetation more Noisy Miner free? Ecological Management & Restoration, vol.7 no.2, pp.105-112
Noisy miners are Australian honeyeaters that naturally occur in Tasmania as well as other states. They are an aggressive species that can dominate bush remnants, excluding small birds, and they are increasing in abundance in eastern Australia. They favour forest edges, open forest/woodland and degraded bush (e.g., where understorey has been removed, remnants smaller than 10 ha and public parks). Because of their aggressiveness (they have even been seen to attack a small bird flying 50 m above their patch!), noisy miners are seen as a threat to the survival of small woodland birds within their range. Some eucalypt dieback has also been related to noisy miner dominance, as the lack of small birds means that insects can increase populations and defoliate the trees.
Recent research (Hastings & Beattie, 2006) has focussed on revegetation sites and what factors encourage noisy miners compared with other native birds. Revegetation is often aimed at encouraging native wildlife and providing wildlife corridors linking remnants, but if newly revegetated areas become dominated by noisy miners, the benefits may be limited.
The research found that noisy miners can take up residence in a revegetation site, and that they can exclude small birds. The good news is that there are ways to discourage noisy miners and encourage other species. Noisy miners did not occur in sites where:
- At least 20% of the site was covered by shrubby understorey.
- Less than 85% of the canopy trees were eucalypt, and the remaining trees were bipinnate acacias (i.e. wattles with "feathery" leaves, such as silver wattles and black wattles).
Sites with a mix of eucalypts and bipinnate wattles in the canopy were the ones most favoured by birds (other than noisy miners).
It seems that wattles are not a good food source for noisy miners, but are desirable for small birds such as thornbills and give them somewhere to hide from the miners.
A more open structure would provide little refuge for small birds to hide from the miners, and nectar bearing shrubs such as grevilleas and callistemons would provide too much good food for the miners. It is possible that noisy miners avoid sites with a proportion of trees or shrubs with dense foliage and low food benefit, because to dominate them would take too much energy for a low return.
Hopefully this research will encourage revegetators, farmers and plantation managers to include understorey plants and bipinnate wattles (such as the undervalued silver wattle) in any plantings.
It is best to imitate all aspects of nearby healthy natural remnants when planning revegetation, as much as is possible considering the conditions of the site. (For instance this article has not mentioned the values of native grasses and sags for butterflies and other fauna.) There are many benefits of having all the components of a natural ecosystem, which science is still only beginning to uncover. And of course noisy miners also have their place. With this information we hope to encourage other birds to keep theirs!