Belongs within: Ardeidae.
Egretta, the egrets, is a genus of colonially-breeding herons known for the feathery plumes that they grow in the breeding season. They also possess powder-down patches on the thighs in addition to those on the breast and rump (Heather & Robertson 1996). Many egrets are white in colouration but the genus also includes darker-coloured species such as the white-faced heron Egretta novaehollandiae and the little blue heron E. caerulea. The Pacific reef heron E. sacra has both white and dark forms, as does the reddish egret E. rufescens of the northern Neotropical region. The tricoloured heron E. tricolor has a blue-grey head, neck and back and a white belly.
<==Egretta Forster 1817 (see below for synonymy)CC10 |--+--E. caeruleaJT12 | `--+--E. rufescensJT12 | `--E. tricolorJT12 `--+--E. novaehollandiae (Latham 1790)JT12, CC10 (see below for synonymy) | |--E. n. novaehollandiaeCC10 | `--E. n. nanaCC10 [=Ardea novaehollandiae nanaHR96] `--+--E. eulophotes (Swinhoe 1860)JT12, I92 `--+--*E. garzetta (Linnaeus 1766)CC10, JT12, CC10 (see below for synonymy) | |--E. g. garzettaCC10 | |--E. g. dimorpha Hartert 1914CS77 | |--E. g. immaculata (Gould 1846) (see below for synonymy)CC10 | `--E. g. nigripes (Temminck 1840)CC10 [=Ardea garzetta nigripesCC10, S90] `--E. thulaJT12 Egretta incertae sedis: E. ardesiacaJT12 E. candidissimaS18 [=Garzetta candidissimaSS66] ‘Herodias’ egrettaS18 ‘Herodias’ galatea [incl. H. leuce]F43 E. gularis (Bosc 1792) [=Ardea gularis]CS77 |--E. g. gularisCS77 `--E. g. schistacea (Hemprich & Ehrenberg 1828)CS77 [=E. garzetta schistaceaSU93] ‘Herodias’ pacificaN87 E. picataSU93 E. sacra (Gmelin 1789)CC10 (see below for synonymy) |--E. s. sacra (see below for synonymy)CC10 `--E. s. albolineataCC10 [=Ardea albolineataS13, Herodias albolineataS13] E. vinaceigulaJT12 Nomen nudum: Egretta brevipes Verr. & Murs 1862S13
Egretta Forster 1817 [=Garzetta Kaup 1829, Erodias Brehm 1832, Erodius Macgillivray 1842 non Fabricius 1775, Herodias Boie 1822; incl. Demegretta Blyth 1852, Demiegretta Baird 1858, Demigretta Blyth 1846, Hemiegretta Bonaparte 1857, Notophoyx Sharpe 1895; Herodiini]CC10
*Egretta garzetta (Linnaeus 1766)CC10, JT12, CC10 [=Ardea garzettaCC10, *Garzetta garzettaCC10, *Herodias garzettaCC10; incl. A. elegansS66, A. xanthopodaS66]
Egretta garzetta immaculata (Gould 1846) [=Herodias immaculata; incl. E. garzetta kempi Mathews 1916, H. melanopus Gould 1865 non Ardea melanopus Wagler 1829]CC10
Egretta novaehollandiae (Latham 1790)JT12, CC10 [=Ardea novaehollandiaeCC10, *Notophoyx novaehollandiaeCC10, Ardea leucops Wagler 1827CC10; incl. N. novaehollandiae parryi Mathews 1912WS48]
Egretta sacra (Gmelin 1789)CC10 [=Ardea sacraCC10, A. (Herodias) sacraCC10, Demiegretta sacraCC10, Demigretta sacraCC10; incl. Demigretta matook carteri Mathews 1920WS48, *Demiegretta concolorCC10, Demigretta sacra tormenti Mathews 1912WS48]
Egretta sacra sacra (Gmelin 1789) [incl. Ardea cinerea Ellman 1861 non Linnaeus 1758, A. jugularis Wagler 1827, A. iugularis, A. matook Vieillot 1817, Demigretta sacra matook, Herodias matook, H. pannosus Gould 1848, Ardea pannosa, H. pannosa]CC10
*Type species of generic name indicated
References
[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.
[CS77] Cramp, S., & K. E. L. Simmons (eds) 1977. Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palaearctic vol. 1. Ostrich to Ducks. Oxford University Press: Oxford.
[F43] Fraser, L. 1843. On the collection of birds brought to England by Mr. Bridges. Proceedings of the Zoological Society of London 11: 108–121.
[HR96] Heather, B. D., & H. A. Robertson. 1996. The Field Guide to the Birds of New Zealand. Viking: Auckland.
[I92] Iwahashi, J. (ed.) 1992. Reddo Deeta Animaruzu: a pictorial of Japanese fauna facing extinction. JICC: Tokyo.
[JT12] Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. Ø. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444–448.
[N87] North, A. J. 1887. List of references to authentic descriptions of Australian birds’ eggs. Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 1163–1174.
[S13] Sarasin, F. 1913. Die Vögel Neu-Caledoniens und der Loyalty-Inseln. In: Sarasin, F., & J. Roux (eds) Nova Caledonia: Forschungen in Neu-Caledonian und auf den Loyalty-Inseln. A. Zoologie vol. 1 pt 1 pp. 1–78, pls 1–3. C. W. Kreidels Verlag: Wiesbaden.
[S66] Schlegel, H. 1866. Communication from, on mammals and birds collected in Madagascar. Proceedings of the Zoological Society of London 1866: 419–426.
[SS66] Sclater, P. L., & O. Salvin. 1866. Catalogue of birds collected by Mr. E. Bartlett on the River Uyacali, Eastern Peru, with notes and descriptions of new species. Proceedings of the Zoological Society of London 1866: 175–201.
[SU93] Sonobe, K., & S. Usui (eds.) 1993. A Field Guide to the Waterbirds of Asia. Wild Bird Society of Japan: Tokyo.
[S18] Stone, W. 1918. Birds of the Panama Canal Zone, with special reference to a collection made by Mr. Lindsey L. Jewel. Proceedings of the Academy of Natural Sciences of Philadelphia 70: 239–280.
[S90] Storr, G. M. 1990. Birds of Shark Bay area, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 299–311. Western Australian Museum.
[WS48] Whittell, H. M., & D. L. Serventy. 1948. A systematic list of the birds of Western Australia. Public Library, Museum and Art Gallery of Western Australia, Special Publication 1: 1–126.