KiWI

*Kiwi (Apteryx spp.) – The Flightless Night Marvel of New Zealand

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Introduction
The *kiwi* (genus _Apteryx_) is a group of flightless, nocturnal birds endemic to New Zealand. Named after the sound of its shrill call—_“ki‑wi”_—the kiwi is a national icon, appearing on coins, logos, and even the nickname for New Zealanders (“Kiwis”). Despite its small size, it has outsized cultural and ecological significance.

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Taxonomy & Naming
- *Family:* Apterygidae (Kiwi, sole family in order Apterygiformes).
- *Genus:* _Apteryx_ – five recognized species:
1. *_Brown Kiwi (_A. australis__)
2. *_Little Spotted Kiwi (_A. owenii__)
3. *_Great Spotted Kiwi (_A. haastii__)
4. *_Rowi (_A. rowi__)
5. *_Tokoeka (_A. mantelli__)
- *Etymology:* _Apteryx_ = “without wing” (Greek _a‑_ = without, _pteryx_ = wing).
- *Māori name:* _Kiwi_ (also reflects the bird’s call).

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Description
- *Size:* Small to medium, roughly the size of a domestic chicken.
- Height: 25–45 cm (10–18 in).
- Weight: 0.8–3.5 kg (1.8–7.7 lb) depending on species.
- *Plumage:* Soft, hair‑like, brown‑gray feathers with a shaggy, mottled appearance; no visible tail.
- *Wings:* Vestigial – only 2–3 cm long, hidden under feathers; no flight capability.
- *Bill:* Long, slender, slightly decurved; nostrils at the tip (unique among birds).
- *Legs:* Strong, muscular, with sharp claws; used for scratching soil.
- *Eyes:* Small, adapted for low light; vision limited, relies heavily on smell.
- *Sexual dimorphism:* Females slightly larger; males have a slightly shorter bill.

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Habitat & Distribution
- *Range:* Throughout New Zealand’s main islands (North, South, Stewart, and several offshore islands), but now mostly confined to predator‑controlled sanctuaries and island reserves.
- *Habitat:* Temperate forests, scrub (e.g., _kunzea_, _manuka_), tussock grasslands, and coastal dunes. Prefer moist, dense understory with soft soil for probing.
- *Elevation:* Sea level to 1,500 m (mountain beech forest).

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Behaviour & Ecology
Diet
- *Omnivorous forager:*
- *Invertebrates:* Earthworms, beetle larvae, wētā, snails.
- *Plant matter:* Seeds, berries, fallen fruit.
- *Foraging method:* Uses long bill to probe soil and leaf litter; *keen sense of smell* (highly developed olfactory bulb) detects prey underground.

Nocturnality
- Active at night; spends daylight hours in burrows, hollow logs, or dense vegetation.
- Emits a *shrill, whistling call* (“ki‑wi, ki‑wi”) at dusk and dawn for territory and mate contact.

Reproduction
- *Monogamous pairs* (often lifelong).
- *Breeding season:* June–March (varies by species).
- *Nest:* Simple burrow or hollow, lined with leaves.
- *Egg:* One (rarely two), extraordinarily large—up to *25 % of female body weight* (e.g., 400 g in a 1.5 kg bird).
- *Incubation:* 70–92 days (male primarily).
- *Chick:* Precocial, fully feathered, leaves nest within a week but stays with parents for several months.

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Conservation Status
Species IUCN (2023) Population Trend
Brown Kiwi (A. australis) Vulnerable Decreasing
Little Spotted Kiwi (A. owenii) Near Threatened Stable (island sanctuaries)
Great Spotted Kiwi (A. haastii) Vulnerable Decreasing
Rowi (A. rowi) Endangered Increasing (intensive management)
Tokoeka (A. mantelli) Vulnerable Decreasing
*Threats*
- *Introduced predators:* Stoats, ferrets, cats, dogs, rats.
- *Habitat loss:* Deforestation, farming, urban expansion.
- *Road mortality* and disturbance.

*Conservation actions*
- *Predator‑free islands* (e.g., Kapiti, Little Barrier).
- *Captive breeding & “Operation Nest Egg”* (eggs incubated in captivity, chicks released after 6 weeks).
- *Fencing, baiting, and community “Kiwi Guardians” programs.*

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Interesting Facts
- *Smell over sight:* Kiwi has the largest olfactory bulb (relative to brain size) of any bird—detects earthworms 15 cm underground.
- *Egg size record:* Largest egg-to-body ratio of any bird; a kiwi egg is ~ 15