Noisy miners live in colonies of dozens of birds that mob intruders collectively. Woodland patches held by a miner colony show markedly reduced diversity and abundance of smaller birds, particularly other insectivores and honeyeaters, because the miners attack and expel them continuously rather than only during breeding.
The species has benefited enormously from land clearing. It prefers open woodland with little understorey, exactly the structure produced by thinning forest for grazing and by planting street trees over mown grass. Fragmentation created a large surplus of edge habitat, and the miners expanded into it.
Aggressive exclusion of birds from potential woodland and forest habitat by abundant noisy miners has been recognised in Australia as a Key Threatening Process under national environment legislation. The difficult part is what follows: culling produces short-lived local effects, and restoring dense understorey, which makes habitat unattractive to miners, is slower but more durable. Which approach works at scale is not resolved.