Rufous night-heron (Nycticorax caledonicus)

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Rufous night-heron fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Rufous night-heron description

Also known as the nankeen night heron, the rufous night-heron (Nycticorax caledonicus) is a stocky, medium-sized heron with a short neck and a relatively short, thick beak ^{(2) (4) (5) (6)}. The adult rufous night-heron is easily identified by its black cap and its reddish-brown back, tail and wings, from which it gets its common name ^{(2) (3) (4) (5)}.

The underparts of the rufous night-heron are white, its face and neck are whitish with a reddish-brown wash, and there may be a white line around its eye ^{(2) (5) (6) (7)}. The undersides of the wings are white, with cinnamon-brown flight feathers ⁽²⁾. During the breeding season, this species develops two or three long, narrow white plumes on its head, which drape down over the back ^{(2) (4) (6) (7)}.

The rufous night-heron’s beak is black, and outside of the breeding season there is a patch of yellowish-green skin between the beak and the eye, which is yellow. In breeding birds, this patch of skin turns blue and the eyes may turn bright red. The rufous night-heron has relatively short, thick legs, and its legs and feet vary from greenish to ochre-yellow or bright yellow, turning bright pink during the breeding season ^{(2) (3) (4) (7)}.

The male and female rufous night-heron are similar in appearance ^{(2) (5) (7)}, but the female is usually slightly smaller than the male ⁽²⁾. Juvenile rufous night-herons are quite different in appearance to the adults, being heavily spotted and streaked all over with buff, brown and white ^{(2) (3) (4) (5) (7)}.

Five subspecies of rufous night-heron are generally recognised, with a sixth subspecies, Nycticorax caledonicus crassirostris, now being extinct ^{(2) (3) (7)}. The subspecies are mainly separated by differences in their size, colouration and distribution ^{(2) (3) (5)}. However, even in a single area the rufous night-heron can be very variable in appearance, with its upperparts ranging from pale cinnamon to a deep maroon ^{(2) (3) (7)}. The reddish-brown upperparts of the adult rufous night-heron help to separate it from its close relative the black-crowned night-heron (Nycticorax nycticorax) ^{(2) (7)}.

The rufous night-heron gives a hoarse, croaking ‘quok’ or ‘wock’ in flight ^{(2) (5)}, as well as a harsh croak or quack when feeding in a group ^{(2) (7)}.

Also known as

nankeen night heron, nankeen night-heron, rufous night heron.

Synonyms

Ardea caledonica.

Size

Length: 55 - 65 cm ⁽²⁾

Wingspan: 95 - 110 cm ⁽³⁾

Weight

550 - 1,014 g ^{(2) (3)}

Rufous night-heron biology

As its common name suggests, the rufous night-heron is largely nocturnal, feeding at night and roosting by day in dense vegetation, often in large groups ^{(2) (5) (6) (7)}. However, during the breeding season it may also feed during daylight hours, to enable it to collect enough food for its chicks ^{(2) (3) (6) (7)}.

The rufous night-heron is an opportunistic feeder, and its varied diet includes fish, amphibians, insects and their larvae, molluscs, and crustaceans such as crayfish, crabs and shrimps. It also feeds on the eggs and chicks of other birds, and will even take mice and newly hatched sea turtles, as well as feeding on refuse at rubbish dumps ^{(2) (3) (4)}. The rufous night-heron generally feeds alone ^{(2) (3)}, but will also occasionally feed in groups ⁽²⁾. This species typically feeds by standing motionless or walking slowly through water before rapidly striking at prey with its beak ^{(2) (3) (4) (6) (7)}. It has also sometimes been seen wading deeper into water in search of prey ⁽⁷⁾.

The breeding season of the rufous night-heron is variable and typically depends on rainfall and food availability. However, it usually runs from October to March in Australia, from February to May in the Philippines, and from February to June in Java ^{(2) (3) (5) (7)}. This species can potentially nest at any time of year given suitable conditions ^{(2) (3) (7)}.

Although it occasionally nests in solitary pairs, the rufous night-heron more commonly nests in large colonies of up to 3,000 pairs, often with other birds such as cormorants, ibises and other heron species ^{(2) (3) (4) (7)}. The nest consists of a loose platform of sticks built in a tree or large bush, usually standing in or overhanging water ^{(2) (3) (6) (7)}. In some locations, such as on islands without trees, the rufous night-heron will also nest on the ground, or even in caves or under rocky overhangs ^{(2) (3) (7)}, with the nest consisting of nothing more than a few sticks to prevent the eggs rolling away ^{(2) (6) (7)}.

The rufous night-heron lays two to five pale greenish-blue eggs, with two to three eggs being most common ^{(2) (3) (7)}. Both adults help incubate the eggs, which hatch after about 21 days ^{(2) (3)}. The young rufous night-herons start to leave the nest at two to three weeks old, scrambling about among the branches and returning to the nest to be fed ^{(2) (6)}. The young birds are not able to fly until they are around six to seven weeks old ^{(2) (3) (6)}.

Each pair of rufous night-herons typically produces a single brood of young each year, but if conditions are favourable a further breeding attempt may occasionally occur ^{(2) (3)}. This species does not usually start to breed until it develops its full adult plumage at around three years old ^{(2) (3)}, but younger individuals have sometimes been known to breed while still in their juvenile plumage ^{(2) (4) (7)}.

Rufous night-heron range

The rufous night-heron occurs from the Philippines, through Indonesia and New Guinea to Australia, the Solomon Islands, Palau, New Caledonia and the Caroline Islands ^{(2) (3) (4) (5) (7) (8)}. Attempts to introduce this species to New Zealand in the mid-1800s failed ^{(2) (7) (9)}, but the rufous night-heron was found breeding there in the 1990s ⁽⁹⁾. The extinct subspecies N. c. crassirostris was found only in the Bonin Islands of Japan ^{(2) (3) (7)}.

Although the rufous night-heron is generally not migratory, it may sometimes make local movements in response to water availability, and some southern populations appear to move north quite regularly in winter. Juvenile birds may also disperse quite widely once they reach independence ^{(2) (3)}.

Rufous night-heron habitat

The rufous night-heron inhabits a variety of wetland habitats, from coasts to inland areas and from permanent water bodies to temporary pools. It is commonly found in areas with shallow water and surrounding vegetation, such as swamps, lakes, rivers, wet meadows, and even dry grasslands. Saltwater habitats are used less often, but the rufous night-heron may sometimes be found on offshore islands, rocky shores, beaches, estuaries, salt marshes, mangrove swamps and coral reefs ^{(2) (3)}.

This species often roosts or even breeds in urban areas ^{(2) (3) (7)}, and also readily uses altered habitats such as flooded pastures, ornamental ponds, parks, gardens, road edges and rubbish dumps ^{(2) (3)}. The rufous night-heron has been recorded at elevations of up to 1,600 metres in New Guinea ^{(2) (3)}.

Rufous night-heron status

The rufous night-heron is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Rufous night-heron threats

The rufous night-heron is a common and widespread species, and is not currently considered to be at risk of extinction ⁽⁸⁾. The subspecies N. c. crassirostris of the Bonin Islands became extinct by the late 1800s ^{(2) (3) (7)}, but the reasons for its extinction are unclear.

Rufous night-heron conservation

There are no specific conservation measures currently known to be in place for the rufous night-heron.

Find out more

Find out more about the rufous night-heron and its conservation:

• BirdLife International - Rufous night-heron:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=3743
• Birds in Backyards - Nankeen night-heron:
  http://www.birdsinbackyards.net/species/Nycticorax-caledonicus
• IUCN SSC Heron Specialist Group - Rufous night heron:
  http://www.heronconservation.org/styled-5/styled-48/

More information on conservation in Australia:

• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/
• Australian Conservation Foundation:
  http://www.acfonline.org.au/
• BirdLife Australia:
  http://www.birdlife.org.au/

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Glossary

Crustaceans

Diverse group of animals with jointed limbs and a hard chitinous exoskeleton, characterised by the possession of two pairs of antennae, one pair of mandibles (mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, woodlice and barnacles.

Flight feathers

The feathers at the end of the wing, involved in flight.

Incubate

To keep eggs warm so that development is possible.

Larvae

Stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Nocturnal

Active at night.

Plume

An ornamental feather that is usually long and conspicuous, and is used by a bird for display.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (February, 2013)
   http://www.iucnredlist.org/
2. IUCN SSC Heron Specialist Group - Rufous night heron (February, 2013)
   http://www.heronconservation.org/styled-5/styled-48/
3. del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
4. McKilligan, N. (2005) Herons, Egrets and Bitterns: Their Biology and Conservation in Australia. CSIRO Publishing, Collingwood, Australia.
5. Kennedy, R.S., Gonzales, P.C., Dickinson, E.C., Miranda Jr, H.C. and Fisher, T.H. (2000) A Guide to the Birds of the Philippines. Oxford University Press, Oxford.
6. Burton, M. and Burton, R. (2002) International Wildlife Encyclopedia. Third Edition. Marshall Cavendish, New York.
7. Hancock, J. and Kushlan, J. (2010) The Herons Handbook. A&C Black Publishers, London.
8. BirdLife International - Rufous night-heron (February, 2013)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=3743
9. Marsh, N. and Lövei, G.L. (1997) The first confirmed breeding by the nankeen night heron (Nycticorax caledonicus) in New Zealand. Notornis, 44: 152-155.