Arikah Map

Heron

For other uses, see Heron (disambiguation).
iHerons
Heron:Snowy Egret, Egretta thula. Note the chicks in the nest.
Snowy Egret, Egretta thula. Note the chicks in the nest.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Ciconiiformes
Family: Ardeidae
Leach, 1820
Genera

See text.

The herons are wading birds in the Ardeidae family. Some are called egrets or bitterns instead of herons.

Within the family, all members of the genera Botaurus and Ixobrychus are referred to as bitterns, and—including the Zigzag Heron or Zigzag Bittern—are a monophyletic group within the Ardeidae. However, egrets are not a biologically distinct group from the herons, and tend to be named differently because they are mainly white or have decorative plumes.

The classification of the individual heron/egret species is fraught with difficulty, and there is still no clear consensus about the correct placement of many species into either of the two major genera, Ardea and Egretta. Similarly, the relationship of the genera in the family is not completely resolved. For example, the Boat-billed Heron is sometimes classed as a heron, and sometimes given its own family Cochlearidae, but nowadays it is usually retained in the Ardeidae.

Although herons resemble birds in some other families, such as the storks, ibises and spoonbills, they differ from these in flying with their necks retracted, not outstretched.

The members of this family are all primarily associated with wetlands, and prey on fish, frogs and other aquatic species. Some, like the Cattle Egret, also take large insects, and are less tied to watery environments. Some members of this group nest colonially in trees, others, notably the bitterns, use reedbeds.

In February 2005, the Canadian scientist Dr. Louis Lefebvre announced a method of measuring avian IQ in terms of their innovation in feeding habits. Herons were named among the most intelligent birds based on this scale, reflecting a wide variety, flexibility and adaptiveness to acquire food.


Contents

Taxonomy

Analyses of the skeleton, mainly the skull, suggested that the Ardeidae could be split into a diurnal and a crepuscular/nocturnal group which included the bitterns. From DNA studies and skeletal analyses focusing more on bones of body and limbs, this grouping has been revealed as incorrect (McCracken & Sheldon, 1998). Rather, the similarities in skull morphology reflect convergent evolution to cope with the different challenges of daytime and nighttime feeding. Today, it is believed that three major groups can be distinguished (Sheldon et al., 2000), which are (from the most primitive to the most advanced):

FAMILY ARDEIDAE

Subfamily Tigrisomatinae

Subfamily Botaurinae

Subfamily Ardeinae

Other prehistoric and fossil species are included in the respective genus accounts.

The night herons could warrant separation as subfamily Nycticoracinae, as it was traditionally done. However, the position of some genera (e.g. Butorides or Syrigma) is unclear at the moment, and molecular studies have until now suffered from a small number of studied taxa. Especially the relationship among the ardeidine subfamily is very badly resolved. The arrangement presented here should be provisional.

Trivia

The Norwegian municipality of Tysvær has a heron in its coat-of-arms.

See also

References

Categories


Ardeidae | Bird families | Heraldic birds

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