North Island Brown Kiwi Apteryx mantelli Scientific name definitions

50–65 cm; male 1440–3060 g, bill 110–155 mm, female 2060–3850 g, bill 130–205 mm. Flightless nocturnal bird with rotund appearance , lacking visible tail, and with very long, slightly decurved bill  and short thick legs; plumage appears hair-like. Plumage stiffer than in Southern Brown Kiwi, back more rufous-coloured and with heavier dark streaking, bill greyer, legs usually brown, scutes ranging from blackish to brown or grey, skin between scutes much paler. Sexes similar in plumage, female larger and longer-billed than male. Juvenile  is similar to adult , but smaller, feathers softer, more downy although no real downy stage exists in this species.

Until recently, considered conspecific with A. australis and hitherto undescribed A. rowi, but differs from other taxa previously lumped with it in having brown vs grey, rufous or dark brown plumage (1); stiff vs soft feather tips (2); 17 vs <7 large tarsal scutes (3); long vs short facial bristles (2); presence of unique species of feather louse (= ecological difference) (1 Palma, R.L. and Price, R.D. (2004). Apterygon okarito, a new species of chewing louse (Insecta: Phthiraptera: Menoponidae) from the Okarito brown kiwi (Aves: Apterygiformes: Apterygidae). New Zealand J. Zool. 31(1): 67–73. Close ) (1). Various genetic studies show the three to be well separated (2 Baker, A.J., Daugherty, C.H., Colbourne, R. and McLennan, J.L. (1995). Flightless Brown Kiwis of New Zealand possess extremely subdivided population structure and cryptic species like small mammals. Proc. Natn. Acad. Sci. USA 92(18): 8254–8258. Close , 3 Burbidge, M.L., Colbourne, R.M., Robertson, H.A. and Baker, A.J. (2003). Molecular and other biological evidence supports the recognition of at least three species of brown kiwi. Conservation Genetics. 4(2): 167–177. Close , 4 Shepherd, L.D. and Lambert, D.M. (2008). Ancient DNA and conservation: lessons from the endangered kiwi of New Zealand. Mol. Ecol. 17(9): 2174–2184. Close , 5 Herbert, J. and Daugherty, C.H. (2002). Genetic variation, systematics and management of kiwi (Apteryx spp.). Pp. 11–34 in: Overmars, F. ed. (2002). Some early 1990s Studies in Kiwi (Apteryx spp.) Genetics and Management. Science & Research Internal Report 191. Department of Conservation, Wellington, New Zealand. URL: http://www.doc.govt.nz/documents/science-and-technical/ir191a.pdf (download Apr 2013). Close ). Monotypic.

Introduced to several small islands off North I.

North I, New Zealand.

Subtropical to temperate forest and shrublands, especially wet forests of podocarps and hardwoods; nowadays found also in plantations, e.g. of exotic pines (Pinus), and in scrub and farmland, including pasture.

Mostly invertebrates from soil and leaf litter; a small proportion of fruit, seeds and leaves. Invertebrates especially insects, e.g. bugs (Hemiptera), larval and adult beetles (Coleoptera), and cranefly larvae (Tipulidae); also earthworms (Oligochaeta), spiders (Araneae), snails (Mollusca), amphipods, millipedes (Diplopoda), centipedes (Chilopoda). Nocturnal ; mainly solitary . Searches ground and detects prey mainly by smell; bill  then inserted by means of back-and-forth levering motion of head and neck.

Male gives loud, rising and then falling whistle, transcribed as “ah-eel”, less than 1 second long, repeated c. 20 times in series, used as contact and to advertise territory; audible to at least 1·5 km. Female version a shorter, more guttural “ah-eh”, in somewhat slower series of up to c. 20; often calls after male finishes a calling series. Both sexes also give nasal grunts during feeding, perhaps as contact call, also various growls in aggression or when handled by human. In aggressive encounters at territorial borders, snorting sounds and bill-snapping frequent.

Similar to Southern Brown Kiwi. Clutch 1–2 eggs  . Incubation by male on North I; incubation period 75–84 days; hatchling fully feathered  ; young leave nest  nightly to feed alone after 5–6 days, independent at 14–20 days, fully grown at 18–20 months. Male sexual maturity at 14 months, female at 2 years. Breeding parameters on Ponui I, where there is a high density population perhaps reminiscent of pre-human New Zealand, found to differ: most clutches (69%) were of one egg and nest  re-use frequent; nesting success (47%) high for kiwis and fledging success very high (89%) (6 Ziesemann, B., Brunton, D. H. and Castro, I. C. (2011). Nesting success and breeding ecology in a high-density population of Brown Kiwi (Apteryx mantelli). Emu. 111: 148–154. Close ). Long-lived, generation time 10–15 years.

VULNERABLE. Formerly widespread throughout North I and N part of South I, but populations now fragmented; locally common in Northland, and sparsely distributed in Coromandel Peninsula, Bay of Plenty area, Gisborne S to N Ruahine Range, and from Taranaki E to Tongariro; stable populations on Little Barrier I (c. 1000 individuals), Kawau I and Pounui I. Population has probably declined by at least 90% since 1900. Global population estimated at 35,000 birds in 1996, and 25,000 birds in 2008 BirdLife International (2017) Species factsheet: Apteryx mantelli. Downloaded from http://www.birdlife.org on 28/12/2017. . In 2015, the estimated number of individuals in the four main populations was: 8200 in Northland, 1000 on Little Barrier I, 1700 on Coromandel Peninsula, 7150 in E North I and 7500 in W North I. The combined total of c. 25,550 birds is similar to the 2008 estimate, indicating that the population has remained stable for the last eight years, although still declining at 2.5% per year at some unmanaged sites (7 Robertson, H.A., Colbourne, R.A., Graham, P.J., Miller, P.J. and Pierce, R.J. (2010). Experimental management of Brown Kiwi Apteryx mantelli in central Northland, New Zealand. Bird Conservation International. 21(2): 207–220. Close ). The species disappeared from much of North I following destruction of native woodland, but largest counted population of this race (800–1000 birds) is in commercial plantation at Waitangi. On North I, at least 94% of chicks perish before reaching breeding age, about half of them killed by introduced predators, primarily stoat (Mustela erminea) and cats (Felis catus), also domestic dogs (Canis familiaris), e.g. a single dog killed c. 500 individuals in one population in period of six weeks; continuing clearance of habitat fragments remains a threat to small populations.