Pacific heron

Ardea pacifica Latham, 1802

Order: Ciconiiformes

Family: Ardeidae

New Zealand status: Native

Conservation status: Vagrant

Other names: white-necked heron, whitenecked heron, white necked heron

Geographical variation: Nil

Pacific heron. Non-breeding adult. Menindee Lakes, New South Wales, Australia. Image © Sonja Ross by Sonja Ross

Pacific heron. Non-breeding adult. Menindee Lakes, New South Wales, Australia. Image © Sonja Ross by Sonja Ross

The name ‘Pacific heron’ implies that this is a far ranging bird, when in fact it is rarely seen beyond Australia and Papua New Guinea. It is a tall elegant bird, and similar in size and proportions to the white heron, and markedly larger than a white-faced heron. Pacific herons are common throughout Australia other than the arid interior, and regularly visit Tasmania and New Guinea. One was seen on Norfolk Island in 1978, and birds have reached New Zealand on at least twelve occasions.

The name ‘Pacific heron’ is preferred to the alternative ‘white-necked heron’, as the latter is also used for the cocoi heron (Ardea cocoi) of South America.

Identification

The Pacific heron is a large, long-legged bird with the long neck, small head and pointed bill, typical of all herons. The head, neck and breast are white except for a series of grey circular markings running centrally down the lower neck onto the breast. The back, upper wings and tail are very dark grey (maroon when breeding), and the under-wings are greyish brown. In flight a prominent white patch shows at the elbow. The bill, legs and toes are black. Flight is slow and laboured, on broad, rounded wings. The neck is folded back in flight, and the legs extend past the tail. The usual flying height is up to 50 metres, however Pacific herons use updrafts to soar and glide to much greater heights.

Voice: a harsh croak, usually given in flight.

Similar species: partially leucistic white-faced herons can have entirely white heads and necks, but are much smaller and paler birds compared to the big, blackish (other than head and neck) Pacific heron.

Distribution and habitat

Pacific herons are found in wetlands, lakes, rivers, swamps or boggy grasslands throughout most of Australia most notably in the Murray-Darling River system. They prefer freshwater locations but occasionally can be found in estuarine areas. Pacific herons migrate to otherwise arid inland areas if heavy rain events create temporary lakes and wetlands. They also use farm dams, irrigation channels or roadside drainage ditches.

New Zealand records

There are twelve accepted records of Pacific herons in New Zealand: Methven (April-July 1952), Macauley Island, Kermadec Islands (November 1980), Onepu, Houhora (October 1981), Waipu (January 1984), Hokitika (June-July 2002), Totara, Timaru (January-March 2003), Toko, Stratford (June 2003), Otapiri, Southland (May 2013), near Wellsford (September 2013), Athol, Otago (December 2013), Oreti River, Southland (April 2014), and Wakefield, Nelson (May 2014).

Behaviour and ecology

Pacific herons are most often seen as singles or in pairs, but can form flocks when moving inland to areas that are flooded after rain. They breed in colonies, often with other heron species, ibises or spoonbills. They can be aggressive when foraging, defending a feeding territory. When foraging, Pacific herons walk at a steady pace, then hesitate with neck extended before lunging at prey.

Food

Pacific herons eat a range of small aquatic and terrestrial animals, but surprisingly, they rarely take fish. Their diet includes insects, molluscs and crustaceans, and they may make use of a hard surface to smash a shell or carapace against to access the meat. Pacific herons glean insects from foliage, and are often seen parting grasses or reeds in search of food. They sometimes steal food from other birds, and will eat carrion.

Websites

http://en.wikipedia.org/wiki/White-necked_Heron

References

Heather, B.D.; Robertson, H.A. 1996. The field guide to the birds of New Zealand. Viking, Auckland.

Marchant, S.; Higgins, P.J. (eds) 1990. Handbook of Australian, New Zealand and Antarctic birds. Vol. 1, ratites to ducks. Oxford University Press, Melbourne.

Scofield, R.P. 2010. Ciconiiformes. Pp. 156-168. In: Checklist Committee (OSNZ) Checklist of the birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica (4th ed.). Ornithological Society of New Zealand & Te Papa Press, Wellington.

Recommended citation

Knight, N. 2013 [updated 2015]. Pacific heron. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz

Pacific heron

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