Little Egret – Egretta garzetta

Reference species – published on 27th of January 2018
See Ardeidae family (herons, egrets, bitterns…)
In French: Aigrette garzette en français

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Few birds are so widespread and famous, even among non-birder public and, in the same time, so complex and difficult to identify. Having a closer look to that species open many questions on the meaning of species, on the evolution of behaviour, on the interest of colour morphes for a species. Instead of repeating information easy to find on Wikipedia or any birding website, such the fact that it flies with folded neck (as all egrets), that it has a beak adapted for fishing but uses it for other hunting (vertebrates and invertebrates – like do all Ardeidae), that is colonial (how many solitary Egretta do you know?), we prefer to focus on less well-known information that look deeper. Note that since it is protected, the slaughter for plumes has stopped and the population is doing well.

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Somehow, Little Egret is a “super reference”. It uses almost all fishing/hunting strategies of the family. Motionless, running, slow approach, in flight, producing waves with the beak to attract curious fishes, etc. Only missing the “canopy feeding” (putting wings as an umbrella) typical of the Black Heron.

Although apparently rare, it even uses bait, a strategy considered as intelligent (wonder why other strategies, if efficient, would be less intelligent?) often used by Butorides (Green and Striated Herons). Bait can be natural but often man made (such a piece of bread!).

 

Illustration of Bird-in-tuition method

Egretta_garzetta_11eSome genera of Ardeidae are very homogenous and clear cut such squacco/pond herons (Ardeola), little bitterns (Ixobrychus), large bitterns (Botaurus) and others. In opposite, Egretta is weakly delimitated and still unclear. Some former Egretta such Great and Intermediate Egrets complexes are now either placed in large heron genus (Ardea) or their own genus (Casmerodius or Mesophoyx). Cattle Egrets (Bubulcus ssp) look like Egretta but their are more closely related to large herons (Ardea).

In our method, it becomes difficult to know of which species it is a representative. Actually, there are three levels. The common and widespread Little Egret is a perfect example to discover the heron family in general. There is then a group of related species within a few genera (large herons and egrets) that share a lot. Colonial, sociable, opportunistic, no or very weak sexual dimorphism, very short  term breeding conditions (colour of feathers, lores and beak, presence of plumes). Finally, the Little Egret is also giving much information to the Egretta genus, but as some species include in it (for now) are quite different, such Black Heron and Slaty Egret, it is at this level that it becomes more complicated.

Taxonomy and sub-species

Egretta_garzetta11According to the classification we follow here, Little Egret has two or three subspecies. From West Africa to the Philippines, it doesn’t show any geographical variation but Indonesian and Australasian birds are quite different and represent at least one different sub-species, or even two, and might be split in a different species in the future (see photo from Australia further down).

The main problem involves dimorphic taxa of Africa and Indian ocean. Three of them, gularis (West Africa including Cape Verde), schistacea (Indian Ocean and Middle-Eastern coasts south to Kenya and east to India) and dimorpha (Madagascar and coasts of Tanzania and Mozambique) are sometimes considered as sub-species of the Little Egret, three different species, or two species as such, as we do here: E. gularis (including E. g. schistacea) and E. dimorpha (monotypic).

One important point is certainly the dimorphism. Indeed, all those disputed taxa show dark plumage (grey or blackish) in most adult individuals but a little proportion of them are white and sometimes almost indistinguishable from Little Egret (especially dimorpha). In opposite, Little Egret is never or seldom dark. Dark morph of Little Egret is very mysterious. At best very rare, some claim that it is always a result of hybridation with one of the species described above… more research is needed! The reason that coastal (sub-)species are in majority dark has certainly a significant reason… to be followed!

 

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[Species #27 of the Holistic Encyclopedia of Birds project]

List of other species pages: taxonomicalday per day

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All photos and text are © Valéry Schollaert and Marinella Mejia

 

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