Story: Wetland birds
Page 9 – Rails and crakes
Rails (including crakes) are in the family Rallidae, along with gallinules (swamp hens) and coots.
Banded rail – moho-pererū
The banded rail (Gallirallus philippensis) is a strikingly marked bird, usually only glimpsed briefly as it dashes in and out of hiding. It is related to the more familiar weka, but is slimmer, and can fly. Banded rails have colonised most Pacific islands – from Australia and Indonesia eastwards to Niue, and southwards to the subantarctic Macquarie Island.
The banded rail has a long tapered bill and spindle-shaped body, suited to pushing through dense scrub. Its head is usually stretched forward, led by the pointed bill. Its toes are not webbed, but the bird is a good swimmer. It measures around 30 centimetres, including its long tail, and weighs 170 grams.
Breeding pairs stay on their territory year-round. They make cup-shaped nests, well hidden among dense rushes or grasses. Females may lay two or more clutches of around five light-pink or buff eggs from September (spring) through summer. Both parents take turns to incubate the eggs. After hatching, the young follow the parents to feed for two months, and are then evicted from the territory.
The mainland New Zealand subspecies of banded rail is Gallirallus philippensis assimilis. Related forms on Chatham and Macquarie islands are extinct.
Banded rails were once common all over the mainland, but predators and habitat loss have taken their toll. Now they are restricted to four islands west and south-west of Stewart Island, the Nelson–Golden Bay area, and the northern North Island and a few nearby islands. They are a protected native species.
The laugh of death
One of the banded rail’s calls resembles laughter, and its Māori name, pererū, also mimics a laugh. In Māori tradition, when the demigod Māui tried to pass through the body of Hine-nui-te-pō, the goddess of death, the moho-pererū laughed and woke her, bringing death to Māui and to the world.
Banded rails inhabit dense rush, salt marsh or mangrove that surrounds freshwater and coastal waterways. Their diet includes land snails and coastal molluscs, crabs, spiders, insects and worms. They also eat berries and seeds, and sometimes scavenge in rubbish tips. They feed mainly at dawn and dusk.
Auckland Island rail
The Auckland Island rail (Dryolimnas muelleri) is much smaller than the banded rail. It is endemic to the subantarctic Auckland Islands, where it lives only on two predator-free islands. The population is around 1,500 birds.
Spotless crake – puweto
The spotless crake (Porzana tabuensis) is a very small rail, found all over Australasia and the Pacific – but it is so secretive that it is rarely seen. It has several calls, some soft and others strident – one is a loud trilling purr, resembling an alarm clock. It is 20 centimetres long and weighs 45 grams. The spotless crake is a protected native species. Its population is unknown as the birds are difficult to find.
Habitat and breeding
Spotless crakes are thinly scattered over the North Island (including Tiritiri Matangi, Poor Knights and Three Kings islands), and are found in just a few South Island sites. Their usual habitat is raupō (bulrush) and sedge swamps. The birds stay on their territory all year. The nest is made by weaving the top of a clump of sedge, ferns, rushes or grasses into a cup shape, usually with foliage pulled over as a cover.
Marsh crake – koitareke
The marsh crake (Porzana pusilla) is even smaller than the spotless crake – a slender, shy rail about which little is known. It weighs 40 grams, and is 18 centimetres long. The subspecies Porzana pusilla affinis is found only in New Zealand, and is protected. Numbers are unknown – most records are from birds that cats have killed and brought to houses.
The marsh crake’s habitat includes freshwater raupō swamps, salt marsh around estuaries, and alpine wetlands. It is reasonably mobile, and flies mainly at night.