This miner is a grey bird, with a black head, orange-yellow beak and feet, a distinctive yellow patch behind the eye, and white tips on the tail feathers.

As the common name suggests, the noisy miner is a vocal species with a large range of songs, calls, scoldings and alarms, and almost constant vocalisations, particularly from young birds.

The popularity of nectar-producing garden plants, such as the large-flowered grevilleas, was thought to play a role in its proliferation, but studies now show that the noisy miner has benefited primarily from landscaping practices that create open areas dominated by eucalypts.

The noisy miner is a notably aggressive bird, so that chasing, pecking, fighting, scolding, and mobbing occur throughout the day, targeted at both intruders and colony members.

A juvenile can be distinguished by softer plumage, a brownish tinge to the black on its head and the grey on its back, and a duller, greyish-yellow skin-patch behind the eye.

[14] Size variation in the noisy miner over its range follows Bergmann's rule; namely, birds tend to be larger where the climate is colder.

[15] The subspecies leachi also has finer scalloping on the hind-neck than the nominate race, a more intense yellow tinge to the wing panels, and a slightly broader off-white tip to the tail.

[17] It has two broad-frequency alarm calls that are used when mobbing intruders into their territory, or when predators (including humans) are sighted; and a narrow-frequency alarm call that is primarily used when airborne predators are seen, such as the brown falcon (Falco berigora), or other large flying birds, including the Australian magpie (Gymnorhina tibicen) and the pied currawong (Strepera graculina).

[16] The narrow-band call is used in situations where the bird signals the presence of a predator and restricts information about its own location, while the broad-band alarm is used to attract attention,[19] and can initiate mobbing behaviour.

[24] The noisy miner also produces non-vocal sounds by clicking or snapping its bill, usually during antagonistic encounters with other bird species, or when mobbing a predator.

[31] A field study in box-ironbark country in central Victoria found that noisy miner numbers were correlated with the occurrence of yellow gum (Eucalyptus leucoxylon), which reliably produces flowers (and nectar) each year.

[35] 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.

[37] Field work in Victoria showed that 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.

In a ritualised movement, the noisy miner flies out from a perch across an open area, in a rhythmic undulating pattern, usually calling in flight.

Much of the activity within a noisy miner colony is agonistic with chasing, pecking, fighting, scolding, and mobbing occurring frequently throughout the day.

The noisy miner has been recorded attacking an Australian owlet-nightjar (Aegotheles cristatus) during the day, grebes, herons, ducks and cormorants on lakes at the edge of territories, crested pigeons (Ocyphaps lophotes), pardalotes, and rosellas.

Reports include those of two noisy miners repeatedly pecking a house sparrow (Passer domesticus) at the base of its skull and killing it in six minutes; one noisy miner grasping a striated pardalote (Pardalotus striatus) by the wing, while another pecked it on the head until it died; and a sacred kingfisher (Todiramphus sanctus) being chased and harassed for over five hours, and then found dead with a fractured skull.

[52] The female alone builds the nest, which is deep and cup-shaped, woven of twigs and grasses with other plant material, animal hair and spider webs.

It is lined with wool, hair, feathers, flowers or plant down, and padded with a circular mat woven from fibres pulled from the cocoons of the processional caterpillar.

[55] The noisy miner has some of the largest group sizes of any communally breeding bird, with up to twenty males and one female attending a single brood.

Noisy miners were seen to have a range of strategies to increase their breeding success, including multiple broods, laying eggs early in the season, nesting low in the canopy and group mobbing of predators; these measures did not guarantee against nest failure, due to the diversity of potential predators in the noisy miner's open woodland habitat.

It has been recorded turning over the dried droppings of emu (Dromaius novaehollandiae) and eastern grey kangaroo (Macropus giganteus), searching for insects.

[59] In a study of birds foraging in suburban gardens, the noisy miner was seen to spend more time in banksia, grevillea and eucalypt species, and when in flower, callistemon, than in other plants including exotics.

[60] Detailed studies of the diet of the noisy miner record it eating a range of foods including: spiders; insects (leaf beetles, ladybirds, stink bugs, ants, moth and butterfly larvae); nectar (from Jacaranda mimosifolia, Erythrina variegata, Lagunaria patersonia, Callistemon salignus, Callistemon viminalis, eucalypts Argyle apple, sugar gum, yellow gum, grey ironbark, and grey gum, Banksia ericifolia, B. integrifolia, B. serrata, Grevillea aspleniifolia, G. banksii, G. hookeriana, G. juniperina, G. rosmarinifolia, and flowering quince); seeds from oats, wheat and pepper tree; fruit from saltbush, mistletoe and crabapple; frogs and skinks; and other matter, such as bread, pieces of meat and cheese, and food scraps.

[61] Abundant throughout its significant range, the noisy miner is considered of least concern for conservation,[1] and its extreme population densities in some areas actually constitute a threat to other species.

[62] The role played by the noisy miner in the steep decline of many woodland birds, its impact on endangered species with similar foraging requirements, and the level of leaf damage leading to die-back that accompanies the exclusion of insectivorous birds from remnant woodlands, means that any strategy to restore avian diversity will need to take account of the management of noisy miner populations.

A focus of many regeneration projects has been the establishing of habitat corridors that connect patches of remnant forest, and the use of eucalypts as fast-growing nurse species.

Both practices have sound ecological value, but allow the noisy miner to proliferate, so conservation efforts are being modified by planting a shrubby understory with the eucalypts, and avoiding the creation of narrow protrusions, corners or clumps of trees in vegetation corridors.

They were not assimilated into resident populations of miners, but instead wandered up to 4.2 kilometres (2.6 mi) from the release point, moving through apparently suitable habitat occupied by other miners—at least for the first 50 days following translocation.

[63] An unsanctioned cull took place on private rural property over 1991 and 1992, which, combined with extensive and dense plantings of native trees, reportedly resulted in an increase in species diversity.