North Island brown kiwi
Apteryx mantelli Bartlett, 1852
Geographical variation: None formally described, but four geographical forms are recognised for management purposes, based on marked genetic differentiation within the species: Northland, Coromandel, Western, and Eastern.
The only kiwi in the wild in the North Island. Widespread in native forest and scrub, pine forests, rough farmland from sea level to 1400 m north of the Manawatu Gorge. 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. Dark brown, streaked lengthways with reddish brown and black. Feather tips feel spiky. Long pale bill, short dark legs and toes, often with dark claws.
Large brown kiwi. Dark brown spiky feathers streaked with reddish brown and black, long pale bill, short dark legs, toes and claws.
Voice: Male gives a high-pitched ascending whistle repeated 15-25 times, female gives a slower and lower pitched guttural cry repeated 10-20 times.
Similar species: weka have similar brown colours, but are smaller and have a short bill. The calls of weka are also similar, but have two-syllables and usually have fewer repetitions.
Distribution and habitat
Widespread and locally common in native and exotic forests, scrub and rough farmland in Northland and some of its offshore islands, several islands in the Hauraki Gulf, including Little Barrier, Kawau and Motuora, Coromandel Peninsula, Bay of Plenty, Gisborne, northern and western Hawkes Bay, Tongariro, Taranaki, and Whanganui. Newly established populations at Tawharanui (North Auckland), Maungatautari (Waikato), Cape Kidnappers (Hawke’s Bay), Pukaha/ Mt Bruce (Wairarapa) and Rimutaka Range (Wellington). At the time of European settlement they had a wider distribution, especially in North Auckland and the Waikato.
About 25,000 birds in 2008; 1000 on the Coromandel Peninsula, and the rest evenly split between the Northland, Eastern and Western taxa.
Threats and conservation
North Island brown kiwi have disappeared from many lowland sites and around the fringes of their distribution, through a combination of habitat loss and predation by mammalian predators, especially dogs, ferrets and stoats. Hourly call rates across the whole range is slowly declining, but landscape scale management of predators through periodic aerial 1080 (sodium monofluoroacetate) operations, or trapping, has slowed or reversed the declines in many areas. The removal of eggs or young chicks from the wild and the rearing of chicks and juveniles in captivity or in predator-proof crèches, until large enough (1.2 kg) to cope with the presence of stoats, has allowed these populations to increase, or allowed releases into areas where the population had dwindled or become locally extinct.
Eggs can be laid in any month, but the peak of laying is from June to November. The nest is in a short burrow, rock crevice, hollow base of a tree, or in a hollow log. Clutch size is 1-2. The white egg is very large. Incubation is by the male only. Eggs are left unattended during the night, but the time that the male is off the nest declines as incubation progresses.
Behaviour and ecology
Brown kiwi 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. 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. 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.
Brown kiwi eat mostly small invertebrates, especially earthworms and larvae of beetles, cicadas and moths; they also eat centipedes, spiders, crickets and weta, Some small fallen fruit and leaves are eaten.
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.; Colbourne, R.M.; Graham, P.J.; Miller, P.J.; Pierce, R.J. 2010. Experimental management of brown kiwi Apteryx mantelli in central Northland, New Zealand. Bird Conservation International 21: 207-220.
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.
Robertson, H.A. 2013. North Island brown kiwi. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz
North Island brown kiwi
- Social structure
- Breeding season
- Nest type
- Nest description
- Burrow at the 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
- Clutch size (min)
- Clutch size (max)
- Mean egg dimensions (length)
- 124 mm
- Mean egg dimensions (width)
- 80 mm
- Egg colour
- Egg laying dates
- Interval between eggs in a clutch
- 21 days days
- Incubation behaviour
- male only
- Incubation length (min)
- 75 days
- Incubation length (max)
- 90 days
- Nestling type
- Nestling period (mean)
- 5-7 days until first emergence, returns daily until 2-10 weeks old
- Age at fledging (mean)
- 2-10 weeks
- Age at independence (mean)
- 2-10 weeks
- Age at first breeding (typical)
- 4 years
- Maximum longevity
- 21 years (banded), estimated 40 years
- Maximum dispersal
- 22 km