Kiwi bird (bird a day)


October 29, 2008A Bird A DayNo comments

Kiwi (Creative Commons)

Kiwi (Creative Commons)

Kiwi (Creative Commons)

Kiwi (Creative Commons)

The kiwi is a flightless, endangered bird found only in New Zealand (and is also their national symbol). It is sad to think of any bird going extinct. I cringe at the thought. I am saddened by the loss of life.

(I am sharing the following information directly from Wikipedia)

Currently, there are five accepted species (one of which has four sub-species), plus one to be formally described.

* The largest species is the Great Spotted Kiwi or Roroa, Apteryx haastii, which stands about 45 cm (17.7 inches) high and weighs about 3.3 kg. (Males about 2.4 kg) It has grey-brown plumage with lighter bands. The female lays just one egg, with both sexes incubating. Population is estimated to be over 20,000, distributed through the more mountainous parts of northwest Nelson, the northern West Coast, and the Southern Alps.
* The very small Little Spotted Kiwi, Apteryx owenii is unable to withstand predation by introduced pigs, stoats and cats and is extinct on the mainland because of these reasons. About 1350 remain on Kapiti Island and it has been introduced to other predator-free islands and appears to be becoming established with about 50 ‘Little Spots’ on each island. A docile bird the size of a bantam, it stands 25 cm (9.8 inches) high and the female weighs 1.3 kg. She lays one egg which is incubated by the male.
* The Rowi, also known as the Okarito Brown Kiwi or Apteryx rowi, is a recently identified species, slightly smaller, with a greyish tinge to the plumage and sometimes white facial feathers. Females lay as many as three eggs in a season, each one in a different nest. Male and female both incubate. Distribution of these kiwi are limited to a small area on the west coast of the South Island of New Zealand.
* The Tokoeka, Apteryx australis, relatively common species of kiwi known from south and west parts of South Island that occurs at most elevations. It is approximately the size of the Great Spotted Kiwi and is similar in appearance to the Brown Kiwi but its plumage is lighter in colour.
o The Stewart Island Tokoeka, Apteryx australis lawryi, is a subspecies of Tokoeka from Stewart Island.
o The Haast Tokoeka, Apteryx australis ?, is the rarest species of kiwi with only about 300 individuals. It was identified as a distinct form in 1993. It only occurs in a restricted area in South Island’s Haast Range at an altitude of 1,500 m. This form is distinguished by a more strongly downcurved bill and more rufous plumage.
o The Northern Fiordland Tokoeka ( Apteryx australis ?) and Southern Fiordland Tokoeka (Apteryx australis ?) live in the remote southwest part of South Island known as Fiordland. These sub-species of Tokoeka are relatively common and are nearly 40 cm (16 inches) tall.
* The North Island Brown Kiwi, Apteryx mantelli or Apteryx australis before 2000 (and still in some sources), is widespread in the northern two-thirds of the North Island and, with about 35,000 remaining, is the most common kiwi. Females stand about 40 cm (16 inches) high and weigh about 2.8 kg, the males about 2.2 kg. The North Island Brown has demonstrated a remarkable resilience: it adapts to a wide range of habitats, even non-native forests and some farmland. The plumage is streaky red-brown and spiky. The female usually lays two eggs, which are incubated by the male.

New Zealand Kiwi Map (Creative Commons)

New Zealand Kiwi Map (Creative Commons)

The following information is from

Thanks to New Zealand’s ancient isolation and lack of mammals, the kiwi evolved to occupy a habitat and lifestyle that elsewhere in the world is occupied by a mammal.

It means that in many ways the kiwi is a very unbird-like bird. Its skin is tough as shoe-leather, its feathers are like hair, its bones are heavy, its wings end in a cat-like claw and its body temperature is 38° Celcius, lower than most other birds.

While most birds depend on sight, the kiwi is one of the few birds with a highly developed sense of smell. At night, kiwi can be heard sniffing around in the dark. Alarm them during the day and they run off until, at a distance, they stick their bill in the air, sniffing to see if they are safe from pursuit, just like a wolf or other mammal.

Not only does the kiwi not look like other bird species, many of its characteristics make it more like a mammal than a bird.

Some people speculate that these characteristics are a result of kiwi’s evolution in mammal-free New Zealand. This meant it developed to fill niches filled by mammals elsewhere.

Great Sense of Smell

First, the kiwi is the only bird in the world with external nostrils at the tip of its beak. Its sense of smell is exceptional, second only to the condor, and not by very much.

It can locate food by smell alone. This is thanks to a very well developed olfactory bulb.

Second, the kiwi’s sense of hearing is also well-developed. Its ear openings are large and visible, and a kiwi can often be seen cocking its head to direct its ear at soft or distant noises.

Marrow-filled Bones and Fleshy Footpads

Third, the kiwi skeleton differs from that of other birds, including other ratites. Undeveloped flight muscles give its body a cone-shape, topped with a strong neck and a small head.

Like other ratites, the kiwi does not have a keeled sternum to hold the flight muscles, but it has gone a step further. Because it does not fly, its bones do not have to be super light. So, instead of air sacs, the kiwi’s bones contain marrow. This makes the kiwi’s legs powerful and muscular – they make up a third of its total weight. And, unlike the other ratites, the kiwi has four toes instead of only two or three.

Its large, dinosauric feet mean it can walk almost silently, its tread muffled by fleshy footpads

Fourth, the kiwi’s eye sockets are not separated by a plate as most birds are. Instead, they are divided by large nasal cavities – just like most mammals. Kiwi eyes are small, and are built for nocturnal habits, but they can see well in daylight, and some Southern Tokoeka on Stewart Island emerge from their burrows to forage by day.

Low Blood Temperature

Fifth, kiwi’s blood temperature is much lower than most other birds which range from 39oC – 42oC. The kiwi is more like a mammal, with a temperature between 37oC and 38oC.

Sixth, females have two functional ovaries, unlike other birds… and more like a mammal. If a female produces more than one egg in a clutch, ovulation occurs in alternate ovaries.

Seventh, they build burrows like a badger.

Eighth, its plumage is shaggy and hair-like and it has cat-like whiskers on its face and around the base of its beak – like a mammal.

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