A feral population of emus has been living on Chatham Island, part of New Zealand’s territory roughly 800 kilometers east of the mainland, for more than three decades. The birds descend from just five emus deliberately released on the island over 30 years ago, and a January 2025 drone survey recorded 70 individual sightings across five days of flights, including both adults and juveniles, confirming the population is breeding and self-sustaining.1New Zealand Journal of Zoology. A Drone Survey of a Feral Population of Emu, Dromaius novaehollandiae (Latham, 1790), on Rēkohu / Wharekauri / Chatham Island, Chatham Islands Emus have also been released in several locations on the New Zealand mainland, making the full picture of wild emus in the country more complicated than a simple yes or no.
How Emus Ended Up on Chatham Island
The Chatham Islands, known in te reo Māori as Rēkohu and in Moriori as Wharekauri, sit in the Pacific well east of Christchurch. The archipelago is home to a small human population and a remarkable concentration of endemic wildlife, from the Chatham Island black robin to the Chatham Island oystercatcher. Into this mix, someone introduced five emus sometime in the early 1990s. The release was deliberate, though the exact motivations are not well documented in the scientific literature. Emu farming was a minor agricultural trend in New Zealand during the late 1980s and 1990s, with birds imported from Australia for their oil, leather, and meat. When the emu farming bubble deflated, some owners may have released their surplus stock rather than culling them. That appears to be the backstory for the Chatham Island birds as well.
From those five founders, the population grew without any formal monitoring for decades. Nobody conducted a structured count. Nobody tracked breeding success or range expansion. The birds simply lived on the island, occasionally spotted by farmers and residents, their numbers a matter of local anecdote rather than scientific record. It took until 2025 for researchers to fly drones over the island and get a real sense of how many emus were out there.
What the 2025 Drone Survey Found
In January 2025, researchers used drones to systematically survey the Chatham Island emu population for the first time. Over five days and roughly 303 minutes of flight time, they logged 70 observations of emus: 45 adults and 25 juveniles.1New Zealand Journal of Zoology. A Drone Survey of a Feral Population of Emu, Dromaius novaehollandiae (Latham, 1790), on Rēkohu / Wharekauri / Chatham Island, Chatham Islands That works out to about 13.5 emu observations per drone hour. The presence of juveniles is telling: it means the population is actively reproducing, not just a handful of aging survivors from the original release.
Drone surveys have an important limitation when it comes to counting large birds on vegetated terrain. Dense bush can hide animals from an overhead camera, and without individual identification, the same bird spotted in two flyovers counts twice. The 70 observations are therefore not the same thing as 70 individual emus. The true population could be somewhat smaller if some birds were counted more than once, or larger if others were hidden beneath canopy. Still, the survey established that Chatham Island supports a meaningful breeding population descended from just five birds, a striking example of how quickly large flightless birds can multiply when left alone in a predator-light environment.
Emus on the New Zealand Mainland
Chatham Island is not the only place in New Zealand where emus have gone feral. The same 2025 study notes that emus have been released in several locations across Aotearoa, the mainland, and the researchers advocate for similar drone-based surveys there.1New Zealand Journal of Zoology. A Drone Survey of a Feral Population of Emu, Dromaius novaehollandiae (Latham, 1790), on Rēkohu / Wharekauri / Chatham Island, Chatham Islands Details about these mainland populations are sparse in the published literature. There are scattered media reports and local accounts of emus spotted in the wild on the North and South Islands, but no systematic survey has been published to confirm population sizes or breeding status.
The lack of formal study is itself noteworthy. New Zealand invests heavily in monitoring and managing invasive species, from possums and stoats to wallabies and feral cats. Emus have somehow flown under the radar, figuratively speaking, perhaps because they are not perceived as a serious threat on the same scale as mammalian predators. Whether that perception is justified is an open question, and the Chatham Island survey’s call for mainland studies suggests at least some researchers think it is time to find out.
What Feral Emus Eat
Understanding what emus eat matters because it determines how they interact with the ecosystems they inhabit. In their native Australia, emus are generalist feeders. A study of emu diets in semi-arid New South Wales found they consume large quantities of seeds, fruits, and plant material from a wide range of species.2Emu – Austral Ornithology. Dietary characteristics of Emus (Dromaius novaehollandiae) in semi-arid New South Wales, Australia, and dispersal and germination of ingested seeds They also eat insects and other invertebrates when available. This dietary flexibility is one of the traits that makes emus successful colonizers: they can adapt to whatever food is locally abundant rather than depending on a narrow set of resources.
On Chatham Island, the available plant community is quite different from the Australian outback. The island’s vegetation includes coastal scrub, grasslands, and remnant forest patches. Emus there would be foraging on whatever fruits, seeds, shoots, and invertebrates the landscape provides. Without a detailed dietary study specific to the Chatham Island population, the best assumption is that they are behaving as the generalists they are in Australia, eating broadly and opportunistically.
Seed Dispersal and What It Means for Native Plants
One of the most ecologically significant things emus do is move seeds. They swallow fruits whole, digest the fleshy parts, and pass the seeds out in their droppings, often kilometers from where they ate them. In Australia, emus have been shown to play a meaningful role in long-distance seed dispersal, particularly for plants with large seeds that smaller birds cannot handle.2Emu – Austral Ornithology. Dietary characteristics of Emus (Dromaius novaehollandiae) in semi-arid New South Wales, Australia, and dispersal and germination of ingested seeds Their long gut-retention time means seeds can travel a considerable distance before being deposited.
Whether this seed-dispersal service is helpful or harmful depends entirely on what seeds the emus are spreading. Research on vertebrate herbivores and seed dispersal found that emus in Australia dispersed mostly native plant species, particularly woody plants with large fruits. The overall frequency of alien (non-native) seeds in emu droppings was around 11 percent, even though emus preferentially browsed on non-native plants within any given plant group.3Biological Invasions. Seed dispersal of alien and native plants by vertebrate herbivores In other words, emus ate plenty of weeds but ended up spreading mostly native seeds, because the native plants they consumed tended to be the big-fruited species whose seeds survive digestion.
Translating this to New Zealand requires caution. The plant communities are different, the weed species are different, and the balance of native versus non-native fruiting plants on Chatham Island or mainland New Zealand is not the same as in semi-arid New South Wales. An emu wandering through New Zealand bush might spread seeds of native trees, or it might help distribute invasive plants depending on what it eats. Until someone actually studies the droppings of New Zealand’s feral emus, the ecological impact of their seed dispersal remains genuinely uncertain.
Could Emus Fill the Ecological Niche Left by Moa
This is the question that captures people’s imaginations. New Zealand famously lost its moa, a group of giant flightless birds that filled herbivore niches across the islands for millions of years before human arrival drove them to extinction roughly 600 years ago. Moa ranged from turkey-sized species to the enormous South Island giant moa, which stood over three meters tall. With moa gone, New Zealand lost its large-bodied seed dispersers, browsers, and grazers. Could emus step into that empty role?
The short answer is: only partially, and the overlap is smaller than you might expect. A biomechanical study comparing the skulls and feeding mechanics of emus with those of extinct moa found limited overlap between the emu and one moa species, the upland moa. Both showed some similarities in how stress distributed through their lower jaws during feeding, suggesting they could process similar types of food. But the broader finding was that different moa species exploited their habitats in distinct ways from each other and from living ratites like the emu.4PubMed Central. Moa diet fits the bill: virtual reconstruction incorporating mummified remains and prediction of biomechanical performance in avian giants Moa were not a single ecological type. They ranged from low-browsing generalists to specialized twig-and-leaf eaters. An emu can approximate some of what one moa species did, but it cannot replace the full diversity of ecological roles that nine or more moa species once performed.
There is also the matter of evolutionary context. Moa co-evolved with New Zealand’s plants for tens of millions of years. Many native trees have growth forms thought to reflect defenses against moa browsing, such as the “divaricate” branching pattern common in New Zealand shrubs, where tightly interlocking branches protect inner leaves from large browsers. Emus did not evolve alongside these plants and do not exert the same selective pressures. Introducing an ecological analogue is never the same as restoring the original species, because the web of interactions that shaped both the herbivore and the vegetation no longer exists.
Why New Zealand Authorities Care About Feral Emus
New Zealand takes invasive species management more seriously than almost any other country. The government has set an ambitious goal of making the country free of the most damaging introduced predators by 2050, targeting rats, possums, and stoats in particular. Feral emus sit in a different category from these mammalian predators. They are not stalking native birds in their nests or eating eggs. But that does not mean they are ecologically neutral.
Large herbivores can damage native vegetation through overgrazing, trampling, and soil disturbance. Emus in Australia are known to cause agricultural damage to crops, and the same behavior on Chatham Island could affect both farmland and native plant communities. There is also the seed-dispersal question: if emus are spreading weed seeds into native bush fragments, they could be accelerating the decline of plant communities that conservation managers are working hard to protect. On the other hand, if they are dispersing native seeds into areas where regeneration has stalled, they might be providing a service that has been missing since moa disappeared.
The honest assessment is that nobody knows yet, because nobody has done the fieldwork. The 2025 drone survey was the first step: establishing that the Chatham Island population exists, is breeding, and is large enough to warrant further study. The researchers behind the survey explicitly called for similar work on the mainland, which suggests the scientific community recognizes a gap in knowledge that needs filling before sensible management decisions can be made.
How Five Birds Became a Population
The Chatham Island story is a useful case study in how quickly large birds can establish when conditions allow it. Five emus were released, and within roughly three decades, the population grew to at least several dozen breeding adults with juveniles in tow. Emus in Australia typically lay clutches of five to fifteen eggs, with the male incubating and raising the chicks. If breeding begins at around two years of age and a male successfully raises even a handful of chicks per season, the math favoring population growth gets favorable quickly, especially without significant predation pressure.
Chatham Island has no large terrestrial predators. There are feral cats, which could conceivably take very young chicks, but adult emus are far too large to be vulnerable to any mammal present on the island. This predator-light environment mirrors the conditions that allowed moa to thrive before human arrival. It also means there is no natural check on emu population growth other than food availability and disease. If the population continues growing unchecked, it will eventually be limited by the island’s carrying capacity, but that limit could involve substantial changes to vegetation before it is reached.
Germination After Gut Passage
Not every seed that passes through an emu comes out ready to grow. The Australian dietary study found that seeds of certain species, including common emu-bush and sweet quandong, showed no germination after passing through the emu’s digestive tract. Other species like ruby saltbush and nitre-bush germinated at very low rates.2Emu – Austral Ornithology. Dietary characteristics of Emus (Dromaius novaehollandiae) in semi-arid New South Wales, Australia, and dispersal and germination of ingested seeds So while emus move enormous quantities of seeds across the landscape, the digestive process itself can be harsh enough to kill many of them. The ecological effect depends not just on what the emu eats and where it deposits the seeds, but on whether those seeds are still viable when they arrive.
This matters for New Zealand because the native plants whose seeds emus might consume have not evolved to survive passage through an emu’s gut. Some may handle it fine; others may not. Australian plants that co-evolved with emus may have seed coats adapted to withstand digestive acids and grinding in the gizzard. New Zealand plants, which evolved alongside moa with potentially different gut chemistry and retention times, may or may not survive the same treatment. This is yet another piece of the puzzle that field research on Chatham Island or mainland feral populations could help resolve.
Emus and the Rewilding Debate
In conservation circles, the idea of using ecological analogues to restore lost functions has gained traction in recent years. The concept is sometimes called “rewilding” or “taxon substitution,” and it involves introducing a living species to perform the ecological role of an extinct one. Giant tortoises have been introduced to islands in the Indian Ocean to replace extinct tortoises that once dispersed seeds and managed vegetation. Some ecologists have floated the idea of using emus or other large flightless birds as functional replacements for moa in New Zealand.
The Chatham Island emu population is not the result of a deliberate rewilding program. It is an accidental introduction from the emu farming era. But it has created a natural experiment that rewilding advocates find interesting. Here is a large ratite, living wild on a New Zealand island, interacting with native and non-native vegetation in real time. If researchers study those interactions carefully, the Chatham Island emus could provide data relevant to the broader question of whether ecological analogues can meaningfully restore lost herbivore functions.
The biomechanical evidence suggests the overlap between emus and moa is real but limited.4PubMed Central. Moa diet fits the bill: virtual reconstruction incorporating mummified remains and prediction of biomechanical performance in avian giants Emus might browse and disperse seeds in ways that partially mimic what some moa species once did, but the match is imperfect. And imperfect ecological analogues carry risks. An emu that spreads invasive weeds into native forest remnants is not restoring moa function; it is creating a new problem. The distinction between “helpful analogue” and “harmful invader” may ultimately depend on the specific habitat and whether emus are managed within it or left entirely to their own devices.