Heron

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For other uses, see Heron (disambiguation).

Herons
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.

[edit] 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):

• tiger herons and the boatbill
• bitterns
• day-herons and egrets, and night-herons

FAMILY ARDEIDAE

Subfamily Tigrisomatinae

• Genus Cochlearius
  • Boat-billed Heron, Cochlearius cochlearius
• Genus Tigrisoma
  • Bare-throated Tiger Heron, Tigrisoma mexicanum
  • Fasciated Tiger Heron, Tigrisoma fasciatum
  • Rufescent Tiger Heron, Tigrisoma lineatum
• Genus Tigriornis
  • White-crested Tiger Heron, Tigriornis leucolophus
• Genus Zonerodius
  • New Guinea Tiger Heron, Zonerodius heliosylus

Subfamily Botaurinae

• Genus Zebrilus
  • Zigzag Heron, Zebrilus undulatus
• Genus Ixobrychus
  • Little Bittern, Ixobrychus minutus
  • New Zealand Little Bittern, Ixobrychus novaezelandiae (extinct)
  • Cinnamon Bittern, Ixobrychus cinnamomeus
  • Stripe-backed Bittern, Ixobrychus involucris
  • Least Bittern, Ixobrychus exilis
  • Yellow Bittern, Ixobrychus sinensis
  • Schrenck's Bittern, Ixobrychus eurhythmus
  • Dwarf Bittern, Ixobrychus sturmii
  • Black Bittern, Ixobrychus flavicollis
• Genus Botaurus
  • American Bittern, Botaurus lentiginosa.
  • Great Bittern or European Bittern, Botaurus stellaris
  • South American Bittern, Botaurus pinnatus
  • Australasian Bittern, Botaurus poiciloptilus

Subfamily Ardeinae

• Genus Zeltornis (fossil)
• Genus Nycticorax
  • Yellow-crowned Night Heron, Nycticorax violaceus or Nyctanassa violacea
  • Bermuda Night Neron, Nycticorax carcinocatactes or Nyctanassa carcinocatactes (extinct)
  • Black-crowned Night Heron, Nycticorax nycticorax
  • White-backed Night Heron, Nycticorax leuconotus or Gorsachius leuconotus
  • Rodrigues Night Heron, Nycticorax megacephalus (extinct)
  • Réunion Night Heron, Nycticorax duboisi (extinct)
  • Mauritius Night Heron, Nycticorax mauritianus (extinct)
  • Ascension Night Heron, Nycticorax olsoni (extinct)
• Genus Gorsachius
  • Nankeen Night Heron or Rufous Night Heron, Gorsachius caledonicus or Nycticorax caledonicus
  • White-eared Night Heron, Gorsachius magnificus
  • Japanese Night Heron, Gorsachius goisagi
  • Malayan Night Heron, Gorsachius melanolophus
• Genus Butorides
  • Green Heron or Green-backed Heron, Butorides virescens
  • Striated Heron, Butorides striatus or Ardea striatus
• Genus Agamia
  • Agami Heron, Agamia agami
• Genus Philherodias
  • Capped Heron, Pilherodius pileatus
• Genus Ardeola
  • Indian Pond Heron, Ardeola grayii
  • Squacco Heron, Ardeola ralloides
  • Chinese Pond Heron, Ardeola bacchus
  • Javan Pond Heron, Ardeola speciosa
  • Madagascar Pond Heron, Ardeola idae
  • Rufous-bellied Heron, Ardeola rufiventris
• Genus Bubulcus
  • Cattle Egret, Bubulcus ibis or Ardea ibis
• Genus Proardea (fossil)
• Genus Ardea
  • Great Blue Heron, Ardea herodias
    

    

    Great Blue Heron, Ardea herodias
  • Grey Heron, Ardea cinerea
  • Goliath Heron, Ardea goliath
  • Cocoi Heron, Ardea cocoi
  • White-necked Heron or Pacific Heron, Ardea pacifica
  • Black-headed Heron, Ardea melanocephala
  • Madagascar Heron, Ardea humbloti
  • White-bellied Heron, Ardea insignis
  • Great-billed Heron, Ardea sumatrana
  • Purple Heron, Ardea purpurea
  • Great Egret or Great White Egret, Ardea alba
  • Pied Heron, Ardea picata or Egretta picata
  • Intermediate Egret, Ardea intermedia or Egretta intermedia
  • Swinhoe's Egret or Chinese Egret, Ardea eulophotes or Egretta eulophotes
• Genus Syrigma
  • Whistling Heron, Syrigma sibilatrix
• Genus Egretta
  • Little Egret, Egretta garzetta or Ardea garzetta
  • Snowy Egret, Egretta thula
  • Reddish Egret, Egretta rufescens
  • Slaty Egret, Egretta vinaceigula
  • Black Heron, Egretta ardesiaca
  • Tricolored Heron or Louisiana Heron, Egretta tricolor
    

    

    Tricolored Heron or Louisiana Heron, Egretta tricolor
  • White-faced Heron, Egretta novaehollandiae or Ardea novaehollandiae
  • Little Blue Heron, Egretta caerulea
  • Eastern Reef Egret, Egretta sacra or Ardea sacra
  • Western Reef Heron, Egretta gularis
• Genus undetermined
  • Easter Island Heron, Ardeidae gen. et sp. indet. (prehistoric)

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 considered provisional.

[edit] See also

• Bennu

[edit] References

• McCracken, Kevin G. & Sheldon, Frederick H. (1998): Molecular and osteological heron phylogenies: sources of incongruence. Auk (journal) 115: 127–141. PDF fulltext
• Sheldon, Frederick H.; Jones, Clare E. & McCracken, Kevin G. (2000): Relative Patterns and Rates of Evolution in Heron Nuclear and Mitochondrial DNA. Molecular Biology and Evolution 17(3): 437–450. PDF fulltext

[edit] External links

• Heron videos on the Internet Bird Collection