Pacific Heron Ardea pacifica Scientific name definitions

76–106 cm; 650–860 g (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); wingspan 147–160 cm. Distinguished from Egretta novaehollandiae by all-white head and adult E. picata by larger size, white (not black) head, white neck with darker spotting, and dark (not yellow) bill and legs; juvenile E. picata can have white head and pale to white underparts, but is always smaller, lacks neck spotting and does not have a dark bill or legs. Adult of present species has head and neck white, with black- or chesnut-spotted foreneck and lanceolate, maroon neck plumes when breeding, upperparts sooty to dark grey, becoming dark slate over wings , with white shoulder patch visible in flight (larger when breeding) and greenish sheen to back, tail and wings in breeding season, and slate-grey underparts streaked white, Bare-part colours vary, poorly understood, although bill generally black year-round and eyes yellow to green, whereas lores are dark grey to black during non-breeding period, with pale yellow streak from bill to eye, but become blue in breeding season. Non-breeding adult is duller, with streaked underparts and black spots on foreneck. Juvenile as non-breeding adult  , but head and neck greyish to buff-white, lack neck plumes, has yellow to white mandible and dark brown to bronze-coloured eyes (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Australia (except arid interior); regularly reported in Tasmania, on islands in Bass Strait and in S New Guinea.

Shallow fresh water , flooded grassland, floodplains, rice fields (2 Taylor, I.R. and Schultz, M.C. (2010). Waterbird use of rice fields in Australia. Waterbirds. 33(Spec. Publ. 1): 71–82. Close ), reservoirs (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), ephemeral or fluctuating rivers or swamps, lagoons, pastures and billabongs, all usually with water < 7 cm deep (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Less frequent in salt or brackish water. Recorded to at least 1800 m in Snowy Mts, New South Wales (3 Osborne, W.S. and Green, K. (1992). Seasonal changes in composition, abundance and foraging behaviour of birds in the Snowy Mountains. Emu 92(2):93–105. Close ).

Nomadic, moves about exploiting seasonality of Australian wetlands, e.g. inland of Darwin breeds Jun–Aug, then mostly vacates area between Jan and May (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Normally found along coast during dry season, moving to wetlands of interior during or after rains. Exceptional rainfall in arid areas can lead to irruptions, e.g. 1974 in SE Australia, 1975 in SW Australia and Tasmania, and 1978 and 1979 in E Australia; unusually abundant in Irian Jaya (W New Guinea) in 1978/79. Regular in Papua New Guinea (Transfly, Port Moresby, etc.) and on Bass Strait Is (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Vagrant to New Zealand  , Norfolk I and Yamdena (Wallacea; Sept 2013) (4 Robson, C. (2013). From the field. BirdingASIA. 20: 121–127. Close ).

Small aquatic and terrestrial animals, small birds (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), fish (normally under 3 cm, largest recorded was catfish of 10 cm), amphibians (frogs, newts, tadpoles) (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), lizards (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), molluscs, crustaceans (shrimp, crayfish) and aquatic insects (dragonfly larvae, mantids, grasshoppers, beetles and their larvae) (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), as well as carrion on occasion (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Diurnal , passive feeder, rarely attempting to stab at prey more than once per minute (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); normally feeds alone or in pairs, sometimes defends territory, but also seen in loose feeding flocks, exceptionally numbering several hundred birds (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Observed stealing food from ibises and raptors (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Usually quiet, especially away from nest, but utters guttural croaking sound in alarm, and variety of guttural and cackling calls at nest, while chicks beg using rasping notes (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Usually Sept–Feb (occasionally until Apr) (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), during spring in S and summer rains in N; may occur year-round in wet years, depending on availability of food and water conditions. Normally colonial, in small colonies of 2–30 pairs, but up to several hundred; colonies often mixed with cormorants (Phalacrocorax), spoonbills (Platalea), ibises (Threskiornis) or other herons; occasionally solitary at small waterbodies, exceptionally up to five nests in same tree (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Nest is stick platform (30–60 cm in diameter) (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), usually 15–40 m up tall tree, over or near water, and can be reused in subsequent seasons, with material being collected by males, usually close to nest-site, or from other nests, even in flight from water (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Average clutch 3–4 pale green-blue eggs  (2–6), mean size 58 mm × 39 mm (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); incubation 28–30 days; chicks have greyish-white down, albeit with whiter head and neck, and are fed by both adults (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); fledging c. 6–7 weeks, although youngest chick usually dies and typically only two survive to fledging (1 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Not globally threatened (Least Concern). Common in Australia, especially inland in SE ; population stable, but has expanded to SW of Western Australia since 1950. Has benefited from deforestation carried out to create pastures or irrigation schemes, and also construction of reservoirs, etc. Uncommon and perhaps irregular in Tasmania and S New Guinea.