Great-billed Heron Ardea sumatrana Scientific name definitions

100–115 cm; 1300–2600 g; wingspan 190 cm (1 Kennedy, R. S., P. C. Gonzales, E. C. Dickinson, H. C. Miranda, and T. H. Fisher (2000). A Guide to the Birds of the Philippines. Oxford University Press, Oxford, UK. Close ); bill c. 183 mm. Similar to wholly allopatric and very rare A. insignis, with more slender, slightly recurved bill and darker belly; elongated plumes on back  more in evidence, nuchal crest longer. Brown-grey crown with silver-grey plumes , upper throat pale grey, upperparts generally grey, washed brownish over head, back and neck, lower throat brown-grey, becoming paler over rest of underparts, wings darker brown-grey (paler on undersides); throat and breast become white during breeding season; bill  black above and whitish yellow to greenish below, but develops yellow-green tip and yellow base during breeding season; legs dusky grey to olive grey; irides  yellow to silver-brown, and lores yellow to green, but can be blue-grey during breeding season. Juvenile more rufous and overall paler than adult, with heavier white streaks on neck and underparts, washed rufous or sandy-buff over back and underparts, lacks crest and has bill and legs brown (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Race mathewsae browner (almost bronze-coloured), with shorter bill and tarsi (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Some clinal variation, with darker birds in humid E of range, but paler in drier W (Gloger’s Rule) (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Coastal  , typically affecting mangroves (provided there are tall trees) (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), tidal mudflats and estuaries; also coastal swamps, rivers, beaches, (coral) lagoons, monsoon rainforest (4 Woinarski, J. C. Z. (1993). A cut-and-paste community: birds of monsoon rainforests in Kakadu National Park, Northern Territory. Emu 93(2):100–120. Close ) and islets; occasionally follows large rivers inland for some distance, where it may occupy billabongs, rocky gorges, swamps and creeks (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Has been reported breeding far inland in Kalimantan (Borneo) (5 Holmes, D. A. (1997). Kalimantan bird report 2. Kukila 9:141–169. Close ) and at elevations up to 600 m in New Guinea (6 Beehler, B. M., and T. K. Pratt (2016) Birds of New Guinea: distribution, taxonomy, and systematics. Princeton University Press, Princeton, New Jersey. Close ).

Apparently sedentary, although some records away from breeding grounds may indicate some post-breeding dispersal. Vagrant to NE New South Wales.

Little known. In Australia, mainly fish  , also crabs and other crustaceans; mudskippers taken in Borneo. Large size and huge bill suggest large prey probably taken. Territorial, solitary feeder, rarely in pairs or family groups. Feeds  at low tide, in water up to 30 cm deep (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), flying back to trees as tide comes in. Principally crepuscular during non-breeding season (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).

Considered to be very vocal, giving deep, guttural and resonant “Roaring” calls , transliterated as “hwur HUH hur’hur” (7 Rasmussen, P. C., and J. C. Anderton (2005). Birds of South Asia: the Ripley Guide. Lynx Edicions, Barcelona, Spain. Close ) and likened to an angry bull or a crocodile, given especially at night, when disturbed or in defence of nest, and lasting several seconds and repeated 3–4 times, with several seconds between each call, but sometimes becoming a double roar (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) and may be alternated with strange, hollow-sounding, descending and winnowing groans (7 Rasmussen, P. C., and J. C. Anderton (2005). Birds of South Asia: the Ripley Guide. Lynx Edicions, Barcelona, Spain. Close ). Other described vocalizations include croaks, booming and a sound likened to that of a small engine (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), a loud oscillating but mainly descending groaning sound that commences higher-pitched and more nasal, but becomes a dry braying at its terminus (7 Rasmussen, P. C., and J. C. Anderton (2005). Birds of South Asia: the Ripley Guide. Lynx Edicions, Barcelona, Spain. Close ).

In any month in Australia, generally coinciding with monsoon, May–Jun in N, Sept–Jan in E; May–Jun (break in monsoon) in Singapore; Aug in W Java (with still-downy young in E Java in late May) (8 Grantham, M. (2000). Birds of Alas Purwo National Park, East Java. Kukila. 11: 97–121. Close ); Nov on Simuele I, off W Sumatra. Solitary nester (but occasionally occupies sites close to mixed colonies) (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), apparently forming stable pairs, with several nests (up to seven), though may not breed every year. Stick nest often reused in successive years and is well concealed, usually over water, becoming large, up to 1·3 m wide × 0·5 m deep; up to 10 m off ground in large tree, e.g. Avicennia mangrove, but frequently as low as 2·5 m above ground (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Clutch two pale green-blue eggs  , size 62·5–71 mm × 46·5–49 mm (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); both adults incubate and tend young (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); chick initially has pale grey down, with grey bill and legs (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), and becomes fully feathered at 63 days; usually only one of the two survives to fledge (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ). Few additional data

Not globally threatened (Least Concern). Previously considered Near Threatened. Widespread, but at low densities and species requires better protection of mature mangrove habitats and has probably been extirpated from coastal Vietnam, Cambodia, the Gulf of Thailand (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ) and parts of Indonesia (9 Poole, C. (1996). Around the Orient: Sulu Sea seabird surveys. Bull. Oriental Bird Club. 23: 16. Close ), while old sight records from Nicobar Is (Trinkut, Katchall and Great Nicobar) are considered unacceptable (7 Rasmussen, P. C., and J. C. Anderton (2005). Birds of South Asia: the Ripley Guide. Lynx Edicions, Barcelona, Spain. Close ). Information scarce and on occasions contradictory: in N Australia, said by one authority to be relatively common in suitable habitat, with densities of 2·5–5 birds/km and numbers reportedly stable, but by others to be nowhere common or rare and apparently shrinking in numbers. Australian range appears to have contracted northwards during present century. Scarce in lowlands of New Guinea (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ), but both here and in parts of Indonesia range is still subject to revision, with first records from following islands only reported recently: Flores (1989) (10 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close ), Lembata (1990) (11 Trainor, C.R. (2003). The birds of Lembata (Lomblen), Lesser Sundas. Kukila 12:39–53. Close ), Seram (1996) (12 Ekstrom, J.M.M. and Isherwood, I. (2000). New and noteworthy bird records from the island of Seram, Maluku. Kukila. 11: 51–57. Close ), Ternate (1989) (10 Bishop, K. D. (1992). New and interesting records of birds in Wallacea. Kukila 6(1):8–34. Close ) and Togian Is (Sulawesi; 1996) (13 Indrawan, M., S. Somadikarta, J. Supriatna, M. D. Bruce, Sunarto, and G. Djanubudiman (2006). The birds of the Togian Islands, central Sulawesi, Indonesia. Forktail 22:7–22. Close ). Reportedly widespread in Malay Peninsula, where important sites include Salu–Sudong–Paiwai–Senang group of islands S of Singapore (none of which is protected) (14 Lim Kim Seng (1994). Birds to watch: threatened birds in Singapore. Bull. Oriental Bird Club. 19: 52–54. Close , 2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ); may be relatively frequent in parts of E Sumatra; commonly sighted in W Sulawesi, and regular on Sumbawa (Lesser Sundas) (15 Trainor, C. R., P. J. Benstead, K. Martin, D. Lesmana, D. Agista, M. C. Benstead, R. Drijvers, and I. Setiawan (2006). New bird records for Nusa Tenggara Islands: Sumbawa, Moyo, Sumba, Flores, Pulau Besar and Timor. Kukila 13:6–22. Close ). Known from several protected areas on Borneo, including Bako National Park (Sarawak), Tabin Wildlife Reserve (Sabah) and Kutai National Park (Kalimantan) (16 Mann, C. F. (2008). The Birds of Borneo: An Annotated Checklist. B.O.U. Checklist 23. British Ornithologists’ Union, and British Ornithologists’ Club, Peterborough. Close ), as well as Alas Purwo National Park (E Java) (8 Grantham, M. (2000). Birds of Alas Purwo National Park, East Java. Kukila. 11: 97–121. Close ); in Australia, occurs in Kakadu National Park (Northern Territory) (4 Woinarski, J. C. Z. (1993). A cut-and-paste community: birds of monsoon rainforests in Kakadu National Park, Northern Territory. Emu 93(2):100–120. Close ). Other potentially important sites include the Rhio–Lingga Is and R Kinabatangan in Borneo (2 Kushlan, J. A., and J. A. Hancock (2005). The Herons. Oxford University Press, Oxford, UK. Close ).