Auckland Island rail

Lewinia muelleri (Rothschild, 1893)

Order: Gruiformes

Family: Rallidae

New Zealand status: Endemic

Conservation status: Naturally Uncommon

Geographical variation: Nil

Auckland Island rail. Adult female in captivity. Mount Bruce Wildlife Centre, September 1975. Image © Department of Conservation (image ref: 10036058) by Rod Morris Courtesy of Department of Conservation

Auckland Island rail. Adult female in captivity. Mount Bruce Wildlife Centre, September 1975. Image © Department of Conservation (image ref: 10036058) by Rod Morris Courtesy of Department of Conservation

The Auckland Island rail is a small and extremely secretive rail known from only two islands in the subantarctic Auckland Islands group, where there are probably about 1500 birds. First discovered in the second half of the 19th century, the species went undetected between 1893 and 1966 when it was rediscovered on Adams Island. In 1993 it was found on Disappointment Island. It must have originally occurred on all the islands in the Auckland Islands group but vegetation changes caused by pigs and predation by cats has eliminated it from the main Auckland Island, and the former presence of cattle, rabbits and mice probably explain its absence from Enderby Island. It inhabits dense vegetation and is very secretive, but quite vocal – being much more often heard than seen. It is the only rail resident on the Auckland Islands and when a good sighting is made it cannot be confused with anything else. If however, it is only glimpsed (as it most often is) then it can be confused with the similar-sized subantarctic snipe.

Its closest relative is Lewin’s rail from Australia which is very similar in appearance but a little larger.

Identification   

The Auckland Island rail is a small rail with a reddish-brown head and neck, brown and black back, grey breast, and black-and-white barred flanks and undertail. The bill is red with a grey tip and the legs are grey-brown.

Voice: a characteristic and loud kek-kek-kek…. call and a variety of quiet calls.

Similar species: the only species with which the Auckland Island rail might be confused is the similar-sized subantarctic snipe which occurs everywhere the rail does. The snipe has a much longer bill, a buff-and-brown striped head, and plain (unbarred) flanks and undertail. The snipe is less furtive and slower moving than the rail, and readily flushes if disturbed at close range (the rail never does).

Distribution and habitat

Auckland Island rails are known only from Adams (10,000 ha) and Disappointment (280 ha) Islands in the Auckland Islands group. They undoubtedly once occurred on most of the islands in the group, but vegetation changes caused by pigs and cattle, predation by cats and perhaps competition from mice has eliminated them from the main Auckland Island (51,000 ha) and Enderby Island (600 ha). They may still occur on some smaller islands in the group, but they have not been detected on any of them.

On both Adams and Disappointment Islands they are most often found in dense vegetation about 1 m high comprising tussocks, large herbs and sedges, at sites from sea level to about 450 m a.s.l. On Adams Island they sometimes also occur in short (2.5 m high) forest which has a dense understory of ferns and sedges.

Population

There are probably about 1500 Auckland Island rails, of which about 95% occur on Adams Island.

Threats and conservation

There are no threats to the rails on Adams and Disappointment Islands which have no introduced predators. However, rails have disappeared from islands in the Auckland Islands group that have (or have had) pigs, cats and mice, but it is not clear which of these introduced mammals was responsible for the rail’s demise. There is a risk that any of these mammals might eventually cross the narrow gap between the main Auckland Island and Adams Island and lead to the extinction of the rails there. There is also a risk that rats might arrive on the islands from an illegal landing or shipwreck.

The Auckland Islands are nature reserves with strictly controlled access.

Breeding

Probably spring and summer breeders, though only one active nest has ever been found (in November). The only known clutch contained 2 eggs. Nests are woven of grasses and sedges, about 20 cm above the ground and concealed from above by vegetation.

Behaviour and ecology

Auckland Island rails appear to be territorial, sedentary and diurnal. They spend all their time in the cover of dense vegetation and very rarely fly.

Food

Unknown, but probably almost entirely invertebrates.

Websites

http://en.wikipedia.org/wiki/Auckland_Islands_Rail

http://www.birdlife.org/datazone/speciesfactsheet.php?id=2875

http://nzbirds.com/birds/railaucklandisland.html

References

Elliott, G.P.; Buckingham, R.P.; Walker, K.J. 1991. The Auckland Island rail. Notornis 38: 199-209.

Falla, R.A. 1967. An Auckland Island rail. Notornis 14: 107-113.

Recommended citation

Elliott, G.P. 2013. Auckland Island rail. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz

Auckland Island rail

Breeding season
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Nest type
woven cup
Nest description
Cup woven of grasses, concealed from above by vegetation
Nest height (mean)
0.2 m
Clutch size (mean)
2
Mean egg dimensions (length)
34 mm
Mean egg dimensions (width)
25 mm
Egg colour
Cream coloured with brown, red-brown and pale grey spots and blotches concentrated at the blunt end
Egg laying dates
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Incubation length (mean)
Unknown
Nestling type
precocial
Nestling period (mean)
Unknown
Age at fledging (mean)
Unkinown
Age at independence (mean)
Unknown
Age at first breeding (typical)
Unknown
Maximum longevity
Unknown
Maximum dispersal
Unknown