Herons - Waterside Elegance

Herons, Egrets and Bitterns

Herons, egrets and bitterns all belong to the same family - Ardeidae. They are medium-sized to large birds normally associated with water. Most are long-legged and long-billed, with slender bodies. In flight they can be distinguished from storks or ibises by their kinked (S-shaped) necks. In general, those species which are predominantly white are known as egrets, and those which are not are herons. Bitterns are short-legged, cryptically plumaged, retiring and seldom seen.

In Africa there are 18 species of heron and egret, and three bitterns. They range in size from the impressive Goliath Heron which stands as tall as a man, to the diminutive Dwarf Bittern which is less than foot high.

Stand and Wait, or Stalk and Strike

Herons are predators of frogs, fishes, insects and crustaceans which are captured in one of three ways: standing and waiting, slow stalk or active pursuit. These techniques often involve leg and wing movements to flush or distract prey.

The Black Egret is famous for its unique technique of opening and folding both wings to form an umbrella over the water surface; whether small fish are attracted to the shade, or the shade reduces glare for better visibility, we cannot be sure - but the strategy works!

The bright yellow toes of the Little Egret may perform some role in attracting or flushing fish and frogs. Without doubt the most astonishing feeding technique is that of the Green-backed Heron - a cosmopolitan species which is known in most parts of the world as the Striated Heron. This small heron has been observed to gather and float bait on the water and to then snap up small fish as they come to the surface - one of only a few tool-using birds in the world!

The Black-headed Heron prefers to forage on dry land and is frequently attracted to veld fires where it snaps up feeling or scorched rodents and reptiles.

Not surprisingly, it is the massive Goliath Heron which tackles the largest prey items, with baby crocodiles occasionally on the menu.

All Together at the Heronry

A number of herons and egrets nest colonially in what are aptly called "heronries". Large trees over water, or dense reedbeds, are favoured sites, with dozens or even hundreds of pairs building nests within inches of one another. Cormorants, storks, ibises and other birds frequently nest at the same site and create quite a spectacle.

Unlike storks, which are thought to mate for life, herons and egrets pair up only for the breeding season. To make themselves more attractive, many species develop decorative plumes prior to breeding and the colour of the bill, facial skin and legs becomes brighter or changes altogether.

The nest itself is vigorously defended against neighbours and - with a good deal of nest material theft going on - heronries can be noisy places. Between three and six eggs are laid - depending upon the species - and both sexes share in the incubation and feeding.

Conservation

Because they are all dependent upon aquatic habitats, herons are vulnerable to chemical pollution (toxins may not kill them directly but accumulate in the tissues of their prey) and habitat destruction. Many of the traditional breeding localities have been destroyed due to drainage for agriculture but some of these birds have adapted well to man-made water impoundments and may even be more numerous than they were prior to human settlement.

The bitterns, on the other hand, are sensitive to disturbance and the Eurasian Bittern (which has both resident and migratory populations in Africa) is regarded as globally endangered. The long term protection of wetlands such as the Okavango Delta, St Lucia Estuary, Nile Floodplain, Sudd Swamps and Kafue Floodplain will ensure the survival of most species.

At the turn of the last century, heron species that acquired spectacular plumes were killed in huge numbers for the fashion trade. Populations in North America and elsewhere were severely reduced because adults were slaughtered just as they had begun breeding. Thankfully, the international trade in plumes has been dead for close to a hundred years and is no longer a threat.

Where to see Herons, Egrets and Bitterns at CCAfrica properties

The Grey and Green-backed Heron, together with the Cattle Egret, are ubiquitous, and occur commonly throughout Africa, including all of the CCAfrica properties.

The wetlands in and around Phinda support a wide range of species, including the rare White-backed Night Heron which breeds on the Mzinene River. Floodplains and marshes along the Zambezi River afford guests at Matetsi with great opportunities to see numerous heron species as well as other waterfowl. The pristine Okavango Delta provides habitat for a host of species, and Nxabega or Sandibe are the places to get to it you¹re mad about herons!

Further Reading
Hancock, J & Kushlan, J. 1984. The Herons Handbook. Croom Helm, London & Sydney.

Posted: Birds by CC Africa, Date: 21 November 2006