In a recent query on the Glamorgan Rarities Committee blog regarding Great (White) Egret, John Wilson asked whether Great White Egret should be down in the East Glamorgan Bird Report as Casmerodius albus, following the Collins guide, or as Ardea alba, following the BOU list. Both the BOU and the AOU have been convinced by DNA findings going back to the 1970s that Great White Egret belongs in Ardea, with all the larger herons, thus making Casmerodius albus obsolete.
That seems straightforward. Now for the confusion parts. The British English name for this heron is Great White Egret, whereas the international English name is Great Egret. Dutch Birding Association lists as the English name Western Great Egret, due to their recognition of the split from Eastern Great Egret in the Antipodes. (They do list Western Great Egret as Casmerodius albus though.) The IOC World Bird List has gone back to Great Egret Ardea alba since a relump with A. modesta. Further, there are some who call Great Egret Egretta alba, such as the Swedish Sveriges Ornitologiska Förening.
It does look like Great White Egret is prone to confusion. This is confirmed by the Association of European Record and Rarities Committees, who asked for clarification of placement in an earlier taxonomic recommendation document. Without quoting the entry verbatim, it seems that there are differences of opinion within the taxonomic subcommittee of the AERC. The BOU seems to be content about positioning Great White Egret in Ardea. The Dutch Commissie Systematiek Nederlandse Avifauna and the French Commission de l’Avifaune Française seem less satisfied with this conclusion. They follow the line that Great White Egret takes up a place half-way between herons Ardea and egrets Egretta. Because Great White Egret is not the only species to be in this position (Intermediate Egret and Cattle Egret are the other two species), they deem it better to place GWE in a separate genus Casmerodius until relationships between the various species have been clarified. Although the AERC seems to support the latter position, the Swedish SOF supports the status quo of Egretta alba.
Taking the three names, the language is not particularly dazzling. All three species names refer to the colour white of the bird (albus/alba). The genera are a bit more interesting:
- Ardea = Latin for heron;
- Casmerodius = contraption of Greek khasios, treasure, and erōdios, heron – referring to the value of the display feathers;
- Egretta = from French aigrette, egret.
Heron and egret are related, egret being a small heron – from French aigrette being a diminuitive of aigron. Most European languages follow patterns into similar definitions.
There are references to the colour white: volavka bílá (CS), mjallhegri (IS), airone bianco maggiore (IT) – white heron; czapla biała (PL), garça-branca-grande (PT) – great white heron.
In addition, the adjective silver relates to the colour white (silver white, bright white) not to any valuable assets: sølvhejre (DA), Silberreiher (DE), egretthegre (NO), ägretthäger (SV) – silver heron; grote zilverreiger (NL) – great silver heron.
Further, great egrets are so named in Spanish (garceta grande) and French (grande aigrette), with Greek silver egret (αργυροτσικνιάς).
The odd one out here is the Finnish jalohaikara, noble heron. The nobility element refers to the egret’s elegance, but haikara refers to more birds than just herons (including bitterns and night herons). Storks (e.g. katohaikara – White Stork) and spoonbills (e.g. kapustahaikara, Eurasian Spoonbill) are named haikara too. This could be a result from it having a very long etymology, from possible pre-Germanic haigara or even pre-Proto Germanic kraikr, an onomatopœic representation of the harsh calls.