“A kiwi egg can equal about one-fifth of the female’s body weight.”
The kiwi is a flightless nocturnal bird endemic to New Zealand. North Island brown kiwis probe soft soil with long beaks to find earthworms and insects in native forests.
By An Nguyen · Updated
Apteryx mantelliApterygiformesApterygidae
Browse photographs of kiwi across habitat, behavior, anatomy, and life stages.
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Core article
A closer look at habitat, diet, behavior, reproduction, and conservation.
It looks unlike any other bird on Earth. The North Island brown kiwi (Apteryx mantelli) is a flightless, nocturnal forager with hair-like feathers and nostrils at the very tip of a long beak. Endemic to New Zealand forest, this carnivore probes soft soil after dark for worms and insects — a way of life that also leaves it dangerously exposed to introduced predators.
Adults are about chicken-sized — 18 to 25 inches long and 3 to 8 pounds, females larger than males — with wings reduced to tiny stubs under shaggy, fur-like brown plumage, and strong legs and claws for digging dens and kicking through litter. The bill is the kiwi's signature tool: uniquely among birds its nostrils sit near the tip, so it can smell prey as it probes underground, guided by sensory pits and a sensitive tip that detect the movement of worms and larvae. Small eyes suit night life, where smell and hearing matter far more than sight. Kiwis are ratites, family Apterygidae, and A. mantelli is the most numerous living kiwi. Having evolved without native mammal hunters, kiwis traded flight for strong legs, keen smell, and nocturnal habits — the very traits that left them badly prepared when people brought stoats, dogs, and cats.
North Island brown kiwis occupy native forest, scrub, regenerating bush, and some plantation edges across much of the northern two-thirds of New Zealand's North Island, favouring soft, moist, invertebrate-rich soils with dense understory for daytime cover. They roost by day in burrows, hollow logs, or thick vegetation and emerge after dusk. Densities are far higher on predator-controlled islands and fenced mainland sanctuaries than on open farmland-forest mosaics where stoats and dogs roam.
Kiwis are mainly invertebrate hunters — earthworms, beetle larvae, adult insects, spiders, and centipedes — with the occasional fruit or seed when abundant, but probing soil is the core technique, leaving a night's trail of holes across soft ground. Because the prey is underground, rain and soil moisture matter: drought drives worms deeper and forces longer walks between good patches, and in degraded habitat invasive mammals compete for the same invertebrates. In intact forest with deep litter, foraging stays efficient.
Pairs often share a territory and keep in touch with loud calls that carry through the night forest, reinforcing bonds with mutual preening and shared dens. Otherwise kiwis forage alone and avoid needless fights, defending space by scent rather than combat. Threatened, a kiwi may freeze, bolt for cover, or kick with its powerful legs — but it cannot fly from danger, so survival depends on knowing every den and thicket in its patch. Its nocturnal timing dodges day-active hunters but not stoats, which also hunt after dark. Kiwi and kakapo are both nocturnal, flightless New Zealanders, but their calls serve different social systems; see why kakapos boom at night for the kakapo's lek-based alternative.
Breeding pairs dig or reopen a leaf-lined nest burrow, and the female lays a single, enormous egg — occasionally two — that can be a huge fraction of her body weight. Incubation runs about 70 to 80 days, with the male commonly taking the longer shifts. Chicks hatch fully feathered and open-eyed and can leave the nest to feed themselves within days, though they stay near adults and shared dens. The first months are the bottleneck: introduced predators kill many juveniles before they can establish a territory, but adults that reach maturity may live for decades.
The North Island brown kiwi is Vulnerable, declining overall where predators go uncontrolled — stoats, dogs, cats, and ferrets are the main killers, with habitat fragmentation and vehicle strikes adding losses on the mainland. Conservation leans on trapping, predator-proof fencing, translocation to safe islands, and "Operation Nest Egg"–style programs that hatch eggs in captivity and return young when they are less vulnerable. The results are measurable: managed sites can reverse local declines, while unprotected forests keep losing birds.
Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Apterygiformes
Family
Apterygidae
Genus
Apteryx
Species
A. mantelli
A kiwi egg can equal about one-fifth of the female’s body weight.
Kiwis have nostrils at the tip of the beak — rare among birds.
They are flightless and use strong legs to walk forest trails at night.
Their feathers look more like shaggy hair than typical bird plumage.
Males often do most of the long incubation of the giant egg.
The kiwi is a national symbol of New Zealand.
Select a question to reveal the answer.
A kiwi is a flightless bird found only in New Zealand. The North Island brown kiwi (*Apteryx mantelli*) is the most common living kiwi species.
North Island brown kiwis live in forest, scrub, and regenerating bush across much of New Zealand’s North Island, plus some offshore sanctuaries.
Kiwis evolved without native mammal predators, so they became ground foragers with tiny unused wings and heavy bodies adapted for walking and digging.
They are mostly carnivores that probe soil for earthworms, insect larvae, beetles, spiders, and other invertebrates.
A kiwi egg is enormous for the bird’s size — often close to 15 to 20 percent of the mother’s weight — and may take more than two months to hatch.
Yes. Most foraging happens at night, when they use smell and touch to find prey in leaf litter and soft soil.
The North Island brown kiwi is listed as Vulnerable. Introduced predators such as stoats, dogs, and cats remain the main threat.
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