Endemic to New Zealand, kiwis are the smallest known ratites in the world. Their distinctive build and atypical characteristics made them internationally famous. They are commonly referred to as “honorary mammals,” since even their gestation period resembles that of small mammals.
There are five species of kiwi from the genus Apteryx.
They include Brown kiwi, Great spotted kiwi, Little spotted kiwi, Rowi, and Tokoeka.
“Apteryx” derives from Ancient Greek, meaning “wingless.”
Kiwi birds are the smallest ratites in the world.
Their length ranges from 30 to 65 centimeters, and they weigh up to 3,5 kilograms.
Kiwi are sexually dimorphic.
Females are approximately 20% larger than males.
Their average lifespan ranges from 25 up to 50 years.
Kiwi are flightless birds.
They have vestigial wings that are hardly visible under the feathers.
They are the only birds with nostrils at the end of their beaks.
Even though their beaks reach up to 20 centimeters, they have the shortest beaks of all birds, because beaks are measured from nostrils to the end of their beak.
Their sense of sight is poor, however, their sense of smell is highly developed.
Kiwi bones are heavy, and filled with marrow.
It is quite an unusual trait for birds.
Their feathers evolved into a structure resembling hair.
Kiwis’ short, stout legs make up a third of their body.
Their diet consists mostly of grubs, worms, invertebrates, and seeds.
Occasionally, they eat fruits and amphibians.
Kiwi's closest relative is the elephant bird.
Elephant birds are extinct species from Madagascar.
Rowi is among the rarest of kiwi birds, with approximately 450 individuals alive today.
Kiwi are monogamous.
Males solicit for female attention, and once they succeed, they mate for life. However, if a female is not interested in a certain male, she will scare him off.
The breeding season of kiwi birds lasts from late winter to early summer.
They lay up to six eggs a year.
Chicks hatch after 80 days of incubation.
Kiwi’s egg is up to 20% of a female’s body weight.
It makes their eggs, in proportion to their body size, one of the largest of all birds.
Freshly hatched chicks are fully feathered.
They are also fully independent, feeding on nutritious yolk in sacks, which are attached to their bellies.
It takes approximately 10 to 14 days for a chick to forage its own food.
Kiwis are nocturnal.
It is a common trait among the endemic fauna of New Zealand.
Their natural predators are stoats, ferrets, cats, and dogs.
Because of the high death rate, the kiwi population is managed.
In unmanaged populations, their numbers decline by roughly 2% a year, mostly because of the small survival rate of kiwi chicks in the wild.
The current number of kiwi alive estimate at around 68,000 individuals.
Kiwis are listed as vulnerable.
Only little spotted kiwi are currently listed as near-threatened.
Kiwis hold cultural importance to Māori.
They form a strong spiritual association with kiwi. It has been formally recognized in the Treaty of Waitangi—the political constitution between the Māori population and New Zealand’s government, signed in 1840.