The flightless bird native to New Zealand that has become a national symbol is the kiwi. Kiwis are small, nocturnal, and cannot fly. Their inability to fly is due to their extremely small wings relative to their body size. Kiwis play an important role in the ecology of New Zealand as well as holding cultural significance for the country.
What is a kiwi?
The kiwi is a flightless bird native and endemic to New Zealand. There are five species of kiwi remaining today:
- Great spotted kiwi (Apteryx haastii)
- Little spotted kiwi (Apteryx owenii)
- Rowi (Apteryx rowi)
- Tokoeka (Apteryx australis)
- Brown kiwi (Apteryx mantelli)
Kiwis are small, approximately the size of a domestic chicken. They have hair-like feathers, short legs, large feet, and a long, narrow, pointed beak with nostrils at the tip. Their bones are heavy and solid compared to other birds. Kiwis cannot fly and have extremely small wings relative to their body size. Their wing muscles and bones are also underdeveloped and small.
Kiwi characteristics
Some key facts about kiwis:
– Flightless – Kiwis cannot fly due to their small non-functional wings.
– Nocturnal – They are nocturnal and sleep during the day in burrows. This helps them avoid predators.
– Long beak – They have a long, narrow, pointed beak with nostrils at the tip which they use to probe the ground for food.
– Whiskers – Kiwis have whiskers around their beak which help them locate prey while probing the ground at night.
– Lay large eggs – Kiwis lay eggs that are very large relative to their body size, up to 15-20% of their body weight.
– Male incubates eggs – Unusually, the male kiwi incubates and cares for the eggs.
– Long life span – Kiwis are long-lived birds with lifespans between 25 to 60 years depending on the species.
Why can’t kiwis fly?
Kiwis cannot fly for several evolutionary reasons:
Small wings
Kiwis have extremely small non-functional wings relative to their body size. Their wings measure just 1-15 cm long, far too small to allow flight. Kiwi wing muscles and bones are also significantly reduced and underdeveloped. Without adequately sized and muscular wings, kiwis cannot achieve lift or fly.
Heavy body
Kiwis weigh between 1-5 kg depending on the species. Having a heavy body and weight makes flying more difficult and energy intensive. Their bones are solid and heavy compared to other birds as well.
Lack of predators
New Zealand’s isolation meant it had no predatory mammals or other threats to flightless birds. With no major predators to escape from by flying, kiwis evolving the ability to fly offered little advantage and so they lost that ability over time.
Energy conservation
Flight is extremely energetically costly for birds. Since kiwis lived with no major predators, losing the ability to fly helped conserve energy which could be used for other purposes like breeding and raising chicks.
Environmental niche
New Zealand offered many ground dwelling niches. By becoming flightless, kiwis were better adapted to a life on the forest floor probing for insects and fallen fruits.
Kiwi ecology and behavior
Nocturnal
Kiwis are nocturnal and sleep during the day hidden in burrows. Being active at night helped ancestors of the kiwi avoid diurnal birds of prey that hunt by sight. Today, their nocturnality helps avoid introduced predatory mammals.
Diet
Kiwis probe the forest floor using their long beak and nostrils seeking out invertebrates like insects, larvae and worms. They also consume fallen fruits.
Predators
The main predators of kiwis today are invasive mammals like stoats, ferrets, dogs, and cats. These all arrived after European settlement of New Zealand. Kiwi numbers have declined severely due to predation.
Mating
Kiwi pairs are monogamous and mate for life. Mating occurs between June to March. Kiwis are unusual in that males incubate the eggs and raise the chicks.
Eggs
Kiwi eggs are large, up to 15-20% of the female’s weight. Eggs weigh around 400g. Males incubate the eggs for around 2-3 months before they hatch.
Chicks
Kiwi chicks hatch fully feathered and are able to feed themselves after a few days. Chicks stay in the nest burrow for around 20 days after hatching and are dependent on the male for food for the first few weeks.
Life span
Kiwis are long-lived compared to many other bird species. They live between 25-60 years depending on the species. In captivity they live even longer.
Kiwi conservation
All five kiwi species have experienced dramatic population declines, primarily due to predation by invasive mammals. Other threats come from habitat loss and egg theft by humans. They are now endangered and at risk of extinction. Major conservation efforts are underway to protect kiwis including:
– Habitat restoration
– Predator control and eradication
– Captive breeding programs
– Chick rearing and release
– Public awareness campaigns
– Maori community engagement
Kiwi recovery groups
There are several regional kiwi recovery groups who coordinate conservation activities for kiwi in different areas of New Zealand. These groups carry out activities like predator control, monitoring kiwi populations, and advocating for kiwi conservation. Some of the main groups are:
– Kiwis for Kiwi
– Otanewainuku Kiwi Trust
– Whangarei Kiwi Sanctuary
– Maungatautari Ecological Island Trust
– Tongariro Kiwi Sanctuary
– West Coast Penguin Trust
Cultural significance of kiwi
The kiwi is culturally very significant for New Zealand and a major national symbol. Reasons why the kiwi is so significant include:
Uniqueness to New Zealand
Kiwis are found nowhere else in the world except New Zealand. Kiwis are part of New Zealand’s unique natural heritage.
National identity
The kiwi is recognised worldwide as symbolic of New Zealand. It is closely tied to the country’s national identity.
Appears in symbols
The kiwi appears in the logos of organizations like the Royal New Zealand Air Force and Tourism New Zealand.
Namesake
New Zealanders are informally referred to as “Kiwis” overseas. The kiwi bird is believed to have given New Zealanders this nickname.
Used in products
The kiwi appears widely in commercial branding and naming of products in New Zealand. Examples are the kiwifruit and the clothing brand Kiwi Child.
In Maori culture
In Maori legend, the kiwi is said to have lost its wings racing the huia. Kiwis are important in Maori rituals and stories.
Conservation ethic
New Zealand has a strong conservation ethic represented by high-profile kiwi recovery efforts. Conservation of the kiwi reflects wider values.
Conclusion
The iconic flightless kiwi is a national treasure of New Zealand. As the national symbol it reflects values of uniqueness, identity and conservation. Ongoing protection efforts for the endangered kiwi ensure this special bird has a future in its native land. The kiwi remains vital to New Zealand’s natural and cultural heritage.