Okarito brown kiwi

Apteryx rowi Tennyson, Palma, Robertson, Worthy & Gill, 2003

Order: Casuariiformes

Family: Apterygidae

New Zealand status: Endemic

Conservation status: Nationally Vulnerable

Other names: rowi

Geographical variation: None

Okarito brown kiwi. Adult male. Mana Island, June 2017. Image © Leon Berard by Leon Berard

Okarito brown kiwi. Adult male. Mana Island, June 2017. Image © Leon Berard by Leon Berard

Rowi are confined to a small area of lowland forest inland from Okarito in South Westland, and on a few islands free of mammalian predators. Flightless, with tiny vestigial wings and no tail. Nocturnal, therefore more often heard than seen. Male gives a repeated high-pitched ascending whistle, female gives a deeper throaty cry. Pale greyish brown, streaked lengthways with brown and black; many birds have white patches on the face. Feather tips feel soft. Long and pale bill, short pale legs, toes and claws.

Identification                                                                

The rowi is a large brown kiwi. Pale brown soft feathers streaked with brown and black; long pale bill, short pale legs, toes and claws.

Voice:  Male gives a high-pitched ascending whistle repeated 15-25 times; female gives a slower and lower pitched hoarse guttural call repeated 10-20 times.

Similar species: tokoeka are larger and darker or redder. The calls of weka are similar to the male call, but weka have two-syllable calls, and usually have fewer repetitions.

Distribution and habitat

Rowi are locally common in native lowland forests in a small area of moraine debris inland from Okarito. They have recently been introduced to Mana, Motuara and Blumine Islands, in the Cook Strait region. Before human settlement of New Zealand rowi were widespread throughout the northern South Island and into the southern North Island, as far north as Lake Poukawa (Hawkes Bay).

Population

There were about 375 rowi in 2012. The only breeding population is at Okarito; island populations are either used as crèches or have been established only recently.

Threats and conservation

Rowi disappeared from most of their range in the southern North Island and northern South Island. Since European settlement have been known only from the Okarito area, in roughly the same range as occupied now. Up until the 1990s, they were declining due to recruitment failure caused by predation of chicks and juveniles by stoats, and some adults being killed by dogs and motor vehicles. In 1995, their population was estimated at 160 birds. 'Operation Nest Egg' (the removal of eggs or young chicks from the wild and the rearing of chicks and juveniles in captivity and on Motuara Island, until large enough (1.2 kg) to cope with the presence of stoats), allowed the populations to increase to about 200 birds by 2000. A landscape-scale stoat trapping programme in South Okarito Forest from 2001 to 2005 largely failed to protect chicks from stoat predation. Operation Nest Egg was therefore reinstated, and the population has grown rapidly to the 375 birds in 2012. New populations have been established on Mana and Blumine Islands, but birds have yet to breed at these sites.

Breeding

Rowi eggs are laid from July to January. The nest is in a burrow, hollow base of a tree, or in a hollow log. Clutch size is 1, but sometimes clutches can be overlapped with one freshly laid egg and one close to hatching.  The pale-green egg is very large. Incubation is shared by male and female, with the male doing most incubation by day and duties are shared through the night.

Behaviour and ecology

Rowi are flightless and nocturnal. During the day they rest in a burrow, hollow tree or log, or under thick vegetation and emerge shortly after nightfall. They feed by walking slowly along tapping the ground and when prey is detected they probe their bill into the leaf litter or a rotten log; occasionally plunge their bill deep into the ground. Rowi call occasionally each night to advertise territory and to maintain contact with partners; pairs often duet, with the partner responding a few seconds after the first call has been completed. They are territorial, and fight conspecifics with their sharp claws.

Food

Rowi eat mostly small invertebrates, especially earthworms and larvae of beetles, cicadas and moths; they also eat centipedes, spiders, crickets, weta and freshwater crayfish. Some fallen fruit and leaves are eaten.

Weblinks

http://www.kiwisforkiwi.org

References

Colbourne, R.M. 2002. Incubation behaviour and egg physiology of kiwi (Apteryx spp.) in natural habitats. New Zealand Journal of Ecology 26: 129-138.

Heather, B.D.; Robertson, H.A. 2005. The field guide to the birds of New Zealand. Penguin, Auckland.

Robertson, H.A; Baird, K.; Dowding, J.E.; Elliott, G.P.; Hitchmough, R.A.; Miskelly, C.M.; McArthur, N.; O’Donnell, C.F.J.; Sagar, P.M.; Scofield, R.P.; Taylor, G.A. 2017. Conservation status of New Zealand birds, 2016.New Zealand Threat Classification Series 19. Wellington, Department of Conservation. 27p.

Robertson, H.A.; de Monchy, P.J.M. 2012. Varied success from the landscape-scale management of kiwi Apteryx spp. in five sanctuaries in New Zealand. Bird Conservation International.22: 429-444.

Tennyson, A.J.D.; Palma, R.L.; Robertson, H.A.; Worthy, T.H.; Gill, B.J. 2003. A new species of kiwi (Aves, Apterygiformes) from Okarito, New Zealand. Records of the Auckland Museum 40: 55-64.

Recommended citation

Robertson, H.A. 2013 [updated 2017]. Okarito brown kiwi. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz

Okarito brown kiwi

Social structure
monogamous
Breeding season
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Nest type
burrow
Nest description
Burrow base of hollow tree or hollow log
Nest height (mean)
0 m
Nest height (min)
0 m
Nest height (max)
0 m
Maximum number of successful broods
3
Clutch size (mean)
1
Clutch size (min)
1
Clutch size (max)
1
Egg colour
Pale green
Egg laying dates
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Incubation behaviour
shared
Incubation length (min)
70 days
Incubation length (max)
80 days
Nestling type
semi-precocial
Nestling period (mean)
5-7 days first emergence, returns daily for several months
Age at independence (min)
14 days
Age at first breeding (typical)
4 years
Maximum longevity
34 to 48 years
Maximum dispersal
5 km