Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed marine as Ardea alba
Listed migratory - CAMBA as Egretta alba, JAMBA as Egretta alba
Adopted/Made Recovery Plans
Federal Register of
    Legislative Instruments
List of Migratory Species (13/07/2000) (Commonwealth of Australia, 2000b) [Legislative Instrument] as Egretta alba.
 
Declaration under section 248 of the Environment Protection and Biodiversity Conservation Act 1999 - List of Marine Species (Commonwealth of Australia, 2000c) [Legislative Instrument] as Ardea alba.
 
Environment Protection and Biodiversity Conservation Act 1999 - Update of the List of Migratory Species (12/03/2009) (Commonwealth of Australia, 2009q) [Legislative Instrument] as Egretta alba.
 
State Listing Status
VIC: Listed as Threatened (Flora and Fauna Guarantee Act 1988 (Victoria): February 2014) as Ardea alba
Non-statutory Listing Status
VIC: Listed as Vulnerable (Advisory List of Threatened Vertebrate Fauna in Victoria: 2013)
Scientific name Ardea modesta [82410]
Family Ardeidae:Ardeiformes:Aves:Chordata:Animalia
Species author J.E. Gray, 1831
Infraspecies author  
Reference  
Other names Egretta alba [1004]
Ardea alba [59541]
Ardea alba modesta [86652]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

International: Listed under Appendix II of the Convention on Migratory Species.

Listed under the Japan-Australia Migratory Bird Agreement (JAMBA).

Listed under the China-Australia Migratory Bird Agreement (CAMBA).

These listings were made prior to the elevation of the southern and eastern Asian and Australasian subspecies of Great Egret to full species status as the Eastern Great Egret.

Scientific Name: Ardea modesta

Common Name: Eastern Great Egret

Other Names: Great Egret, Large Egret, White Egret, Great White Egret, Common Egret, White Crane, White Heron or Large Heron.

The Eastern Great Egret was recently elevated to full species status (Kushlan & Hancock 2005; Christidis & Boles 2008). Formerly, birds breeding in southern and eastern Asia and Australasia were treated as a subspecies of the Great Egret (Christidis & Boles 1994; Martínez-Vilalta & Motis 1992; Mayr & Cottrell 1979).

The Eastern Great Egret is a moderately large bird (83–103 cm in length, 700–1200 g in weight) with white plumage, a black or yellow bill and long reddish and black legs. The colours of the bare parts change during the breeding season (Kushlan & Hancock 2005; Marchant & Higgins 1990).

Eastern Great Egrets often occur solitarily, or in small groups when feeding. They roost in large flocks that may consist of hundreds of birds. The species usually nest in colonies and rarely in solitary pairs. Colonies may be mono-specific or commonly mixed with other egrets, herons, ibises, spoonbills and/or cormorants. Breeding colonies in south-eastern Australia typically comprise up to several hundred pairs, but colonies in the Channel Country of Queensland and at the Top End of the Northern Territory may comprise several thousand pairs (Chatto 2000; R.P. Jaensch 2008a, unpubl. data; Kushlan & Hancock 2005; Marchant & Higgins 1990; Phillimore & Recher 2004).

Eastern Great Egrets are widespread in Australia. They occur in all states/territories of mainland Australia and in Tasmania. They have also been recorded as vagrants on Lord Howe, Norfolk and Macquarie Islands (Barrett et al. 2003; Blakers et al. 1984; Hermes et al. 1986; Marchant & Higgins 1990; McKilligan 2005).

Locations of Breeding Populations
In Australia, the largest breeding colonies, and greatest concentrations of breeding colonies, are located in near-coastal regions of the Top End of the Northern Territory. A minimum 20 breeding colonies are confirmed along the coast of the Northern Territory (Chatto 2000). The Channel Country of south-western Queensland and north-eastern South Australia have at least 12 breeding colonies, and colonies are also known in the Darling Riverine Plains region of NSW and the Riverina region of NSW and Victoria. Minor breeding sites are widely scattered across the species' distribution and include sites in western Cape York Peninsula, the central coast of Queensland, north and north-eastern NSW, south-eastern South Australia, south-western Western Australia, the Kimberley region of Western Australia and the Barkly Tablelands in the Northern Territory (R.P. Jaensch 2008a, unpubl. data; Jaensch & Bellchambers 1997; Jaensch & Vervest 1989; Maddock 2000; Marchant & Higgins 1990; McKilligan 2005; Phillimore & Recher 2004).

Locations of Non-breeding Populations
Non-breeding birds have been recorded across much of Australia, but avoid the driest regions of the western and central deserts (Marchant & Higgins 1990; McKilligan 2005).

There are no published estimates of the extent of occurrence of Eastern Great Egrets in Australia.

The area of occupancy of the Eastern Great Egret in Australia is estimated at 408 400 km².

Great Egrets are held in numerous zoos and institutions around the world (International Species Information System 2008). It is not known if any of these populations consist of individuals of the former subspecies modesta, since it has been elevated to full species status as the Eastern Great Egret.

The distribution of the Eastern Great Egret in Australia is not severely fragmented. Eastern Great Egrets are not considered especially susceptible to fragmentation effects because they are highly mobile (R.P. Jaensch 2008, pers. comm.).

The Eastern Great Egret is a widespread species of southern and eastern Asia and Australasia. Breeding populations are located in Pakistan, India, Sri Lanka, Bangladesh, Burma, Thailand, China, Korea, north-eastern Russia, Japan, Indo-China, Indonesia, Papua New Guinea, Solomon Islands, Australia and New Zealand (Kushlan & Hancock 2005; Martínez-Vilalta & Motis 1992).

The global population size of the Eastern Great Egret is estimated at approximately 60 000 to 300 000 individuals. Trends in global population size have not been quantified, but numbers are currently declining in eastern Asia (Wetlands International 2006). The main threat to the Eastern Great Egret is probably alteration of existing wetland habitat (Kushlan & Hancock 2005). The species probably also accumulates, and is affected by, persistent environmental contaminants (Ohlendorf & Marois 1990; Pratt & Winkler 1985; Spalding et al. 2000a, 2000b). The Eastern Great Egret is not recognised as a species by BirdLife International and so has not been assigned a global status. BirdLife International retain modesta as a subspecies of the Great Egret, which is classified as Least Concern at the global level (BirdLife International 2007j).

There has been no systematic survey of the Australian population of the Eastern Great Egret. A preliminary estimate of 60 000 individuals was derived from data on breeding colonies (Jaensch 2003) and supports the current published estimate of 25 000 to 100 000 individuals (Wetlands International 2006). Based on the published estimate, approximately 11 to 74% of the total global population may occur within Australian jurisdiction (BirdLife International 2007j). There is at least occasional movement of individuals from Australia to New Zealand (Warburton 1957; Andrew 1963) and probably regular migration between Australia and southern Papua New Guinea, with tens of thousands of birds reported on Papua's Middle Fly River wetlands in December (Geering et al. 1998; Halse et al. 1996). Although birds move beyond Australian jurisdiction, the main threats to the Australian population, such as reduced water flow to breeding wetlands, are within Australia (R.P. Jaensch 2008, pers. comm.).

The Eastern Great Egret has not been systematically surveyed across its entire range in Australia. Abundance data for the species has been collected during a series of annual surveys of wetland birds conducted across eastern Australia (covering approximately one third of the continent) since 1983 (Braithwaite et al. 1985a, 1985b, 1986, 1987; Kingsford et al. 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1997, 2000, 2003; Porter et al. 2006) and there have been ad hoc counts at several locations around Australia, usually at breeding colonies (Chatto 2000; Jaensch 2003; McKilligan 2005).

A preliminary population estimate of 60 000 individuals was derived from data on breeding colonies (Jaensch 2003) and supports the current published population estimate of 25 000 to 100 000 individuals (Wetlands International 2006). This estimate is based on abundance data collected from 1981 to 2003, including approximately 80 counts of 100 or more birds at single wetlands; non-breeding aggregations usually of hundreds or thousands, but exceptionally more than 10 000 individuals; and breeding colonies mostly of hundreds, but, erratically, of several thousand pairs (Chatto 2000; Jaensch 2003).

The existence or number of subpopulations of the Eastern Great Egret in Australia has not been confirmed or estimated. It is unlikely that genuine subpopulations occur given the broad range and high mobility of the species.

The overall population trends of the Eastern Great Egret in Australia are not well understood (Maddock 2000). This is due, at least in part, to the difficulty associated with assessing trends for a species that occupies individual sites erratically, and often in highly variable numbers, across a wide geographic area. Overall, the Australian population is considered to fluctuate in size (Wetlands International 2006), in recognition of the highly variable availability of suitable wetland habitat.

Aerial surveys of wetland birds in eastern Australia indicate that Eastern Great Egret numbers have fluctuated but tended towards decline over the past two decades (Kingsford et al. 1989, 1990, 1992, 1993, 1994, 1997, 2000, 2003; Porter et al. 2006). This trend is consistent with trends in many other species of wetland birds. These trends may partly reflect the influence of drought conditions associated with long-term natural climatic cycles, but also reflect a loss of habitat due to water harvesting, especially within the Murray Darling Basin (R.P. Jaensch 2008, pers. comm.; Maddock 2000).

A major (80%) decline in numbers was observed at Shortland in NSW from 1988/1989 to 1997/1998 (Maddock 2000) with no evidence of recovery in the years since (Kushlan & Hancock 2005). A decline in numbers has also been reported in Victoria (Maddock 2000). Trends in these populations may be directly connected to pressures associated with declines across eastern Australia, but in some instances may also reflect a loss of habitat in coastal areas due to land development (R.P. Jaensch 2008, pers. comm.).

In contrast to these studies in eastern Australia, surveys by Jaensch and Vervest (1989) suggested that numbers may have increased in south-western Western Australia over several decades during the late 20th century, consistent with an influx of large wetland birds to the region since the 1950s (Serventy & Whittell 1976). However, there has been no reassessment of numbers, despite changes to wetland habitats resulting from extraction of groundwater, salinisation and declining rainfall (R.P. Jaensch 2008, pers. comm.).

Because the presence of water is crucial for breeding of the Eastern Great Egret, it is difficult to determine if recent declines in eastern Australia represent a long-term trend or a response to the current climatic cycle. Continued monitoring will be required for the status of the species to be confirmed (Maddock 2000).

The generation length of the Eastern Great Egret has not been documented, but it may be similar to that of another member of the family Ardeidae, the Great-billed Heron, whose generation length has been tentatively estimated at five years (Garnett & Crowley 2000).

The most important populations of the Eastern Great Egret in Australia, based on the capacity for recruitment and abundance, are the breeding populations that occur at the Top End, in the Channel Country and in the Darling Riverine Plains and Riverina regions. Of these, the Darling Riverine Plains and Riverina populations may be declining due to reduced water flow to colony sites and predicted declines in catchment rainfall. Colonies at the Top End are less susceptible to climate change, but could be threatened in future by the development of new irrigation schemes (irrigation development is already a threat to birds on the Daly River). Colonies in the Channel Country are relatively secure, but are occupied less frequently than those at the Top End, and to the east may be affected by a decline in rainfall.

The Eastern Great Egret is not known to cross-breed with any other species. However, documented accounts of hybridisation between the closely-related Great Egret and other herons (Baumanis 1998; Malosh 2004; McCarthy 2006) suggest that Eastern Great Egrets may also engage in some cross-breeding.

The Eastern Great Egret is widespread in Australia and may potentially occur in a large number of conservation reserves. Large numbers frequent Kakadu National Park, but many colonies at the Top End are not located on protected land. Only one of the twelve confirmed breeding colonies in the Channel Country is located on protected land. Some breeding colonies in southern Australia occur within conservation reserves including Macquarie Marshes Nature Reserve and Bool Lagoon Game Reserve (R.P. Jaensch 2008, pers. comm.).

The Eastern Great Egret has been reported in a wide range of wetland habitats (for example inland and coastal, freshwater and saline, permanent and ephemeral, open and vegetated, large and small, natural and artificial). These include swamps and marshes; margins of rivers and lakes; damp or flooded grasslands, pastures or agricultural lands; reservoirs; sewage treatment ponds; drainage channels; salt pans and salt lakes; salt marshes; estuarine mudflats, tidal streams; mangrove swamps; coastal lagoons; and offshore reefs (Kushlan & Hancock 2005; Marchant & Higgins 1990; Martínez-Vilalta & Motis 1992). The species usually frequents shallow waters.
The Eastern Great Egret may retreat to permanent wetlands or coastal areas when other wetlands are dry (for example, during drought). This may occur annually in some regions with regular wet and dry seasons or erratically where the availability of wetland habitat is also erratic.

The Eastern Great Egret may potentially occur at wetlands that also support a range of other waterbirds or shorebirds, such as the Australian Painted Snipe, which is listed as vulnerable under the EPBC Act, and a number of species that are listed as migratory under the EPBC Act. The Eastern Great Egret is widespread in the Alligator Rivers region of the Northern Territory (Morton et al. 1993a), which is the stronghold of the Alligator Rivers subspecies of the Yellow Chat (Epthianura crocea tunneyi). The Yellow Chat (Alligator Rivers) is listed as endangered under the EPBC Act.

In Australia, the breeding season of the Eastern Great Egret is variable, depending to some extent on rainfall (Geering 1993), but generally extends from November to April (Kushlan & Hancock 2005), with pairs at southern latitudes breeding in spring and summer (particularly November and December), and pairs at more northerly latitudes breeding in summer and autumn (Chatto 2000; R.P. Jaensch 2008a, unpubl. data; Marchant & Higgins 1990).

Eastern Great Egrets usually nest in colonies and rarely as solitary pairs (Kushlan & Hancock 2005; Marchant & Higgins 1990). In Australia, breeding sites are located in wooded and shrubby swamps including mangrove forests (the main habitat of the species in the Top End) (Chatto 2000), Melaleuca swamps (on the eastern coast of Australia and south-western Western Australia) and mixed eucalypt/acacia/lignum swamps (in the Channel Country and Murray-Darling Basin) (Marchant & Higgins 1990).

Pairs construct a shallow platform-like nest of loosely woven sticks in the upper strata of trees or shrubs standing in or near water or sometimes in inundated reed beds (Kushlan & Hancock 2005; Marchant & Higgins 1990; Phillimore & Recher 2004). Females lay two to six, but usually three to five, pale blue or pale green eggs. The eggs are incubated by both parents, but mostly by the female, for a period of 23–29 days. Nestlings are fed and brooded by both parents. The young begin to clamber from the nest at 25–37 days of age. Fledged young make their final departure from the nest or colony at 55–88 days of age (Kushlan & Hancock 2005; Marchant & Higgins 1990).

In Australia, breeding success has been calculated for a colony at Shortland in NSW (Maddock 1986; Maddock & Baxter 1991; Marchant & Higgins 1990) and a colony of free-flying birds on the grounds of Perth Zoo Western Australia (Phillimore & Recher 2004). At Shortland, 91% of nests sampled fledged at least one young (Marchant & Higgins 1990) with an average of 2.1 fledglings per successful nest (Maddock & Baxter 1991). At Perth Zoo, pairs produced an average of 1.4 fledglings per nest (Phillimore & Recher 2004). Breeding failures may occur because of a lack of food for nestlings. This situation may result from drying of ephemeral wetlands or from competition for food between siblings (R.P. Jaensch 2008a, unpubl. data; M.N. Maddock pers. comm. 2001). Nestlings are probably vulnerable to a variety of predators including ravens/crows, raptors and aquatic animals.

The Eastern Great Egret has a diverse diet that includes fish, insects, crustaceans, molluscs, frogs, lizards, snakes and small birds and mammals (Kushlan & Hancock 2005; Marchant & Higgins 1990; McKilligan 2005; Vestjens 1977c).

Eastern Great Egrets exhibit a diverse array of complex foraging behaviours. In simple terms, they mostly forage by wading through shallow to moderately deep water, by standing in water and capturing prey that wanders nearby, or by walking over shore or dry ground. They typically secure their prey by abruptly 'stabbing', or by probing or pecking, with the bill. Prey is taken from water and vegetation but not from sediments (R.P. Jaensch 2008, pers.comm.; Kushlan & Hancock 2005; McKilligan 2005; Recher et al. 1983).

The Great Egret is dispersive and, in parts of its range, migratory (Geering et al. 1998; Kushlan & Hancock 2005; Marchant & Higgins 1990). In Australia, multi-directional post-breeding movements of up to 280 km have been recorded in south-western Western Australia, and similar patterns of movement have been recorded in eastern Australia (McKilligan 2005). The species undertakes some regular seasonal movements, mostly to and from breeding colonies, and towards the coast in the dry season (Marchant & Higgins 1990). There is circumstantial evidence of long-distance migration, with regional differences in reporting rates suggesting that individuals migrate north to winter in tropical northern Australia (Geering et al. 1998; McKilligan 2005), consistent with changes in the availability of suitable wetland habitat.

Regular migration to locations outside of Australia is suspected (Halse et al. 1996) but not confirmed. There are records of irruptive movements of individuals from Australia to New Zealand (Warburton 1957; Andrew 1963) and individuals banded in Australia have been recovered in Papua New Guinea, with regular passage likely to occur across Torres Strait (Draffan et al. 1983; Geering et al. 1998; Halse et al. 1996; Marchant & Higgins 1990; McKilligan 2005). To date, there is no evidence of movement by Australian birds to Indonesia or other regions of south-east Asia.

No information is available on territory sizes of pairs that nest solitarily, but in colonial situations, pairs evidently defend only a small area around the nest, as nests are 'closely packed' (Sharland 1957). Distances between nests are typically greater than those recorded for smaller egrets (R.P. Jaensch 2008, pers. comm.).

In Australia, Eastern Great Egrets appear similar to, and could potentially be confused with, Intermediate Egrets (Ardea intermedia), Cattle Egrets (A . ibis), Little Egrets (Egretta garzetta) and white plumage-morph Eastern Reef Egrets (E. sacra). However, Eastern Great Egrets can be distinguished from each of these species under inspection by a range of contrasting morphological features. Notably, the Eastern Great Egret has the longest neck of these species (1.5 times the length of the body), and usually moves more slowly in flight with a pronounced 'keel' formed by the folded neck. During the early stages of breeding, adults have bright blue-green facial skin, a feature unique among Australian herons (Marchant & Higgins 1990).

Eastern Great Egret numbers may be counted or estimated by area search or by transect-point survey. Surveys can be conducted on foot or from light aircraft (Kingsford et al. 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1997). Identification of egrets to species level can be difficult during aerial surveys, especially where large, mixed-species aggregations occur, and may sometimes be impossible. In such circumstances, ground surveys may be necessary to distinguish between species, although these may not be effective for counting or estimating populations in large wetland systems.

Surveys to determine the presence, activity and species composition of breeding colonies can be effectively conducted from the air, although accurate determination of total numbers and species proportions is often impossible. This is because individual nests often cannot be seen, nests may be vertically layered throughout tree strata and distinguishing between adults and near-fledged young can be difficult. Ground surveys may help to confirm proportions of species and phases of breeding, but often are little more successful in accurately determining total numbers.

In any survey, major disturbance to breeding colonies should be avoided to prevent predation of unattended eggs by crows and accidental departure (falling) from nest of unattended young.

Improved aerial and ground survey methods are required for the species (R.P. Jaensch 2008, pers. comm.).

In Australia, the Eastern Great Egret is threatened by loss and/or degradation of foraging and especially breeding habitat through alteration of water flows (for example harvesting of water for irrigation purposes that prevents or limits inundation of wetlands), drainage and/or clearing of wetlands for development, frequent burning of wetland vegetation used as nest sites, salinisation and invasion by exotic plants (Kushlan & Hancock 2005; R.P. Jaensch 2008, pers. comm.) or fishes.

The most important issue for the conservation of Eastern Great Egrets and other herons in inland regions of Australia is the allocation of water from regulated rivers in sufficient quantity and at appropriate times to maintain suitable wetland conditions (Maddock 2000). Kingsford and Auld (2005) used long-term monitoring data to model the likely effects of three different environmental water flow regimes on the Eastern Great Egret and nine other colonial waterbirds in the Macquarie Marshes of NSW. The restoration of suitable wetland habitat capable of supporting breeding birds is being pursued through initiatives such as the Living Murray restoration program.

Major published studies on the Eastern Great Egret in Australia have been completed by Baxter (1996), Baxter and Fairweather (1998), Geering and colleagues (1998), Maddock (1986), Maddock and Baxter (1991) and Phillimore and Recher (2004).

No recovery, conservation or threat abatement plans have been developed for the Eastern Great Egret in Australia.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Ardea alba in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006bd) [Internet].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:unspecified Ardea alba in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006bd) [Internet].
Natural System Modifications:Dams and Water Management/Use:Alteration of hydrological regimes and water quality Ardea alba in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006bd) [Internet].
Natural System Modifications:Dams and Water Management/Use:Changes in hydrology including habitat drainage Ardea alba in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage, 2006bd) [Internet].

Andrew, I.G. (1963). White Heron Invasion. Notornis. 10:311-315.

Barrett, G., A. Silcocks, S. Barry, R. Cunningham & R. Poulter (2003). The New Atlas of Australian Birds. Melbourne, Victoria: Birds Australia.

Baumanis, J. (1998). Hybridisation zwischen Silberreiher Egretta alba und Graureiher Ardea cinerea in Lettland. Limicola. 12:142-145.

Baxter, G.S. (1996). Provision of supplementary nest material to colonial egrets. Emu. 96:145-150.

Baxter, G.S. & P.G. Fairweather (1998). Does the available foraging area, location or colony character control the size of multispecies egret colonies?. Wildlife Research. 25:23--32.

BirdLife International (2007j). Species Fact Sheet: Casmerodius albus. [Online]. Available from: http://www.birdlife.org.

Blakers, M., S.J.J.F. Davies & P.N. Reilly (1984). The Atlas of Australian Birds. Melbourne, Victoria: Melbourne University Press.

Braithwaite, L.W., M.T. Maher & B.S. Parker (1985b). An aerial survey of wetland bird fauna in eastern Australia - October 1984. CSIRO Division of Wildlife & Rangelands Research Technical Memorandum. 23:1-85.

Braithwaite, L.W., M.T. Maher, J. Holmes & B.S. Parker (1986). An aerial survey of wetland bird fauna in eastern Australia - October 1985. CSIRO Division of Wildlife & Rangelands Research Technical Memorandum. 24:1-116.

Braithwaite, L.W., M.T. Maher, S.V. Briggs & B.S. Parker (1985a). An aerial survey of wetland bird fauna in eastern Australia - October 1983. CSIRO Division of Wildlife & Rangelands Research Technical Memorandum. 21:1-89.

Braithwaite, L.W., R. Kingsford, J. Holmes & B.S. Parker (1987). An aerial survey of wetland bird fauna in eastern Australia - October 1986. CSIRO Division of Wildlife & Rangelands Research Technical Memorandum. 27:1-68.

Chatto, R. (2000). Waterbird breeding colonies in the Top End of the Northern Territory. Parks & Wildlife Commission of the Northern Territory Technical Report. 69.

Christidis, L. & W.E. Boles (1994). The Taxonomy and Species of Birds of Australia and its Territories. Royal Australasian Ornithologists Union Monograph 2. Melbourne, Victoria: Royal Australasian Ornithologists Union.

Christidis, L. & W.E. Boles (2008). Systematics and Taxonomy of Australian Birds. Collingwood, Victoria: CSIRO Publishing.

Draffan, R.D.W., S.T. Garnett & G.J. Malone (1983). Birds of the Torres Strait: an annotated list and biogeographic analysis. Emu. 83:207-234.

Garnett, S.T. & G.M. Crowley (2000). The Action Plan for Australian Birds 2000. [Online]. Canberra, ACT: Environment Australia and Birds Australia. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/action/birds2000/index.html.

Geering, D.J. (1993). The effect of drought-breaking rain on the re-establishment of Egret colonies in north coastal New South Wales. Corella. 17:47-51.

Geering, D.J., M. Maddock, G.R. Cam, C. Ireland, S.A. Halse & G.B. Pearson (1998). Movement patterns of Great, Intermediate and Little Egrets from Australian breeding colonies. Corella. 22:37-46.

Halse, S.A., G.B. Pearson, R.P. Jaensch, P. Kulmoi, P. Gregory, W.R. Kay & A.W. Storey (1996). Waterbird surveys of the middle Fly River floodplain, Papua New Guinea. Wildlife Research. 23:557-569.

Hermes, N., O. Evans & B. Evans (1986). Norfolk Island birds: a review. Notornis. 33:141-149.

International Species Information System (2008). Species holdings. Viewed on 29 April 2008. [Online]. Available from: http://app.isis.org/abstracts/abs.asp.

Jaensch, R. & K. Bellchambers (1997). Waterbird conservation values of ephemeral wetlands of the Barkly Tablelands, Northern Territory. Report to Australian Heritage Commission and Parks & Wildlife Commission of the Northern Teritory.

Jaensch, R.P. (2003). Preliminary Estimates of Population Sizes of Australian Waterbirds, Including EPBC-Listed Species. Canberra: Unpublished report to Environment Australia.

Jaensch, R.P. (2008). Personal communication. May 2008.

Jaensch, R.P. (2008a). Unpublished data. Provided May 2008.

Jaensch, R.P. & R.M. Vervest (1989). Breeding colonies of the Great Egret in Western Australia 1986-88. RAOU Report. 33. Canning Bridge WA RAOU.

Kingsford, R.T. & K.M. Auld (2005). Waterbird breeding and environmental flow management in the Macquarie Marshes, arid Australia. River Research and Applications. 21:187-200.

Kingsford, R.T., J.D.B. Smith & W. Lawler (1989). An aerial survey of wetland birds in eastern Australia - October 1988. NSW National Parks & Wildlife Service Occasional Paper. 8:1-67.

Kingsford, R.T., J.L. Porter & A.D. Ahern (2003). Aerial Surveys of Wetland Birds in Eastern Australia - October 2000-2002. Hurstville, NSW, New South Wales National Parks and Wildlife Service.

Kingsford, R.T., J.L. Porter & R. Ferster Levy (1992). An aerial survey of wetland birds in eastern Australia - October 1991. NSW National Parks & Wildlife Service Occasional Paper. 12:1-40.

Kingsford, R.T., J.L. Porter, A.D. Ahern & S.T. Davis (2000). Aerial Surveys of Wetland Birds in Eastern Australia - October 1996-1999. Hurstville, New South Wales: New South Wales National Parks and Wildlife Service.

Kingsford, R.T., J.L. Porter, J.D.B. Smith & W. Lawler (1990). An aerial survey of wetland birds in eastern Australia - October 1989. NSW National Parks & Wildlife Service Occasional Paper. 9:1-35.

Kingsford, R.T., J.L. Porter, R. Ferster Levy, J.D.B. Smith & P. Holland (1991). An aerial survey of wetland birds in eastern Australia - October 1990. NSW National Parks & Wildlife Service Occasional Paper. 10:1-41.

Kingsford, R.T., L.W. Bratihwaite, N. Dexter & W.Lawler (1988). An aerial survey of wetland bird fauna in eastern Australia - October 1987. CSIRO Division of Wildlife & Ecology Technical Memorandum. 30:1-57.

Kingsford, R.T., R. Ferster Levy & J.L. Porter (1993). An aerial survey of wetland birds in eastern Australia - October 1992. NSW National Parks & Wildlife Service Occasional Paper. 16:1-36.

Kingsford, R.T., R. Ferster Levy & J.L. Porter (1994). An aerial survey of wetland birds in eastern Australia - October 1993. NSW National Parks & Wildlife Service Occasional Paper. 18:1-39.

Kingsford, R.T., S. Tully & S.T. Davis (1997). Aerial surveys of wetland birds in eastern Australia - October 1994 and 1995. Occasional Paper. 28. Hurstville: NSW National Parks & Wildlife Service.

Kushlan, J.A. & J. Hancock (2005). Herons. Oxford, United Kingdom: Oxford University Press.

Maddock, M. (1986). Fledging success of egrets in dry and wet seasons. Corella. 10:101-107.

Maddock, M. (2000). Herons in Australasia and Oceania. In: Kushlan, J.A. & H. Hafner, eds. Heron Conservation. Page(s) 123-149. Sydney, NSW: Academic Press.

Maddock, M.N. (2001). Personal communication. 2001.

Maddock, M.N. & G.S. Baxter (1991). Breeding success of egrets related to rainfall: a six year Australian study. Colonial Waterbirds. 14:133-139.

Malosh, G. (2004). Great Blue Heron x Great Egret in Washington County. Pennsylvania Birds. 18:72-73.

Marchant, S. & P.J.Higgins, eds. (1990). The Handbook of Australian, New Zealand and Antarctic Birds, Volume 1 Part a - Rattites to Petrels. Melbourne, Victoria: Oxford University Press.

Martínez-Vilalta, A. & A. Motis (1992). Family Ardeidae (Herons). In: del Hoyo J., A. Elliott & J. Sargatal, eds. Handbook of the Birds of the World. Page(s) 376-42. Barcelona: Lynx Edicions.

Mayr, E., & G.W. Cottrell (Eds) (1979). Check-list of Birds of the World. Volume 1. Second Edition. Massachusetts, USA: Harvard Museum of Comparative Zoology, Cambridge.

McCarthy, E.M. (2006). Handbook of Avian Hybrids of the World. New York: Oxford University Press.

McKilligan, N. (2005). Herons, Egrets and Bitterns: Their Biology and Conservation in Australia. Melbourne: CSIRO Publishing.

Morton, S.R., K.G. Brennan & M.D. Armstrong (1993a). Distribution and abundance of herons, egrets, ibises and spoonbills in the Alligator Rivers region, Northern Territory. Wildlife Research. 20:23-43.

Ohlendorf, H.M. & K.C. Marois (1990). Organochlorines and selenium in California night-heron and egret eggs. Environmental Monitoring and Assessment. 15:91-104.

Phillimore, R.L. & H.F. Recher (2004). Observations on a Great Egret Ardea alba and Nankeen Night Heron Nycticorax caledonicus colony at the Perth Zoo, Western Australia. Corella. 28:82-86.

Porter, J.L., R.T. Kingsford & S.J. Hunter (2006). Aerial Surveys of Wetland Birds in Eastern Australia - October 2003-2005. Hurstville, New South Wales: New South Wales National Parks and Wildlife Service.

Pratt, H.M. & D.W. Winkler (1985). Clutch size, timing of laying and reproductive success in a colony of Great Blue Herons and Great Egrets. Auk. 102:49-63.

Recher, H.F., R.T. Holmes, W.E. Davis & S. Morton (1983). Foraging behaviour of Australian herons. Colonial Waterbirds. 6:1-10.

Serventy, D.L. & H.M. Whittell (1976). Birds of Western Australia. Perth: University of Western Australia Press.

Sharland, M. (1957). Egreta at Ulmarra, NSW. Emu. 57, no.5:295-301.

Spalding, M.G., P.C. Frederick, H.C. McGill, S.N. Bouton & L.R. McDowell (2000a). Methylmercury accumulation in tissues and its effects on growth and appetite in captive Great Egrets. Journal of Wildlife Diseases. 36:411-422.

Spalding, M.G., P.C. Frederick, H.C. McGill, S.N. Bouton, L.J. Richey, I.M. Schumacher, C.G. Blackmore & J. Harrison (2000b). Histological, neurologic and immunologic effects of methylmercury in captive Great Egrets. Journal of Wildlife Diseases. 36:423-435.

Vestjens, W.J.M. (1977c). Status, habitats and food of vertebrates at Lake Cowal. CSIRO Division of Wildlife Research Technical Memorandum. 12.

Victoria Department of Sustainability and Environment (Vic. DSE) (2007). Advisory List of Threatened Vertebrate Fauna in Victoria - 2007. East Melbourne, Victoria: Department of Sustainability and Environment.

Warburton, H.G. (1957). The White Heron (Egretta alba) in New Zealand. Notornis. 7:98-101.

Wetlands International (2006). Waterbird Population Estimates. Fourth Edition. Wageningen, The Netherlands: Wetlands International.

EPBC Act email updates can be received via the Communities for Communities newsletter and the EPBC Act newsletter.

This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Ardea modesta in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Sat, 19 Apr 2014 13:58:00 +1000.