Herons
Heron Species
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.
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
Source: Wikipedia.org
If you would like to add to or correct any of the above information, or would like to share with the AvianWeb visitors your own experiences, please e-mail the AvianWeb Webmaster.
Photo contributions and articles are welcome!
