Brown Kiwi

Maori Name: Rowi

Apteryx

The Kiwi is a ratite, like the moa, emu, cassowary, rhea and ostrich, all of which have an ancient Gondwanan origin. Like all ratites the kiwi is flightless. The fact that the wings are mere stubs and its sternum has no keel means it has likely never flown and therefore was probably present on the land Zealandia before it broke away from Gondwana. Kiwi are more closely related to the emu than the moa, a fact which only confuses the issue of how they came to be here.

The kiwi is odd because in many ways it is more like a mammal than a bird. It has bone marrow rather than hollow bones like other birds, two working ovaries rather than one, not to mention fur-like feathers, large ears and whiskers, these last which help it move around at night. Other things that relate it to mammals is a lower blood temperature than birds, and the fact that it marks its territory with faeces and, unlike birds, has a keen sense of smell. The kiwi is the only bird with nostrils at the end of its beak which is an effective tool when searching for food as it uses its beak to make deep probes in the earth sniffing out worms and other invertebrates.  Kiwi have very powerful legs and can run quickly.  

There are 5 species of Kiwi in isolated patches around New Zealand: the North Island Brown, Little Spotted, Great Spotted, the Tokoeka and the Rowi. The Rowi in particular was only identified as a distinct species in 2003 and it is certainly the rarest. It differs from the North Island Brown Kiwi (under which it was previously categorised) in its smaller size and greyish colour.

Rowi live in Westland in the broadleaf/podocarp forests around Okarito. There are only about 250 birds that range in an area of 11,000 hectares. This gives each breeding pair a territory of about 100 hectares, which is the largest area for any kiwi.

The Rowi is an average sized kiwi at 2.7 kilograms for a female and 1.9 for the male. They are often able to be distinguished by white facial feathers, which other kiwi don’t have.

About one third of the population has a condition called white eye, which seems to make them totally blind, but due to their other keen senses they still move around effectively and are healthy.

Kiwi have a very distinctive call; the male makes up to 25 repetitive and shrill calls while the female has a more guttural repetitive sound repeated up to 20 times. 

The breeding season lasts from about June to March when food is the most plentiful. Adult kiwi will set up a territory first, prepare the nesting burrow and then mate. Kiwi dig burrows under stones, banks of streams, or in soft flat open ground and the nest is lined with soft leaves, grass and moss.

There will be frequent calling between the birds during this time as they seek the best mate. Due to her larger size the female has the advantage, and mating will occur only when the she allows it. The male will persistently follow her around often for weeks, grunting and tapping her on the neck, and when she finally acquiesces in a crouch position, he climbs on her back, sometimes grasping some of her neck feathers in his beak to hold on. The huge egg takes 30 days to develop in the female and takes up such a large portion of her underbelly she has to spread her legs wide to accommodate it. When eventually the egg is laid, it happens quite quickly and will be about 20% of the mother’s weight.

The Rowi female will lay only one egg for each clutch and may lay as many as 3 eggs over a year. Rowi adults share the incubation which takes up to 10 weeks.

Hatching is exhausting and the chick can take up to 3 days to break free of the egg. When it finally emerges, it already has feathers and looks a like a small version of the adult. The yolk sac to which it is still attached will nourish it for several days before it needs food, and at the age of a week the chick will venture out of the nest on its own in search of food. The beak is very soft at this stage and so the little kiwi will merely forage in the leaves looking for insects.