Pamuzinda, Home to the Green Backed Heron and Water Dikkop
Green Backed Heron
The first of these is the unobtrusive, but very vocal, Green Backed (sometimes called Striated) Heron – Butorides striata. Its body colours are very neutral blends of grey giving it the ability to merge into almost any background.
The dead giveaway to its presence is its raucous screech which sounds as if it has come from a far larger bird. Despite its name I must confess I have never seen one with a green back. Rather the base body colour, including the back, is grey. It is supposedly closely related to the Lava Heron from the Galapagos and, by some, considered con-specific. The Galapagos version has now, however, been granted its own name. I have attached an old slide scan image of a Galapagos Heron, that I took some years ago, for comparison purposes.
One of the unusual traits of it, and its several related species throughout the world, is their ability to fish using bait. With birds living in wild habitats their bait is limited to a feather, leaf or even an insect. This they carefully place within beak’s reach on the water surface and then wait for inquisitive fish to come and investigate. However, in some public parks and open spaces in various countries they have learned to “nick” bits of bread and sandwich from picnickers. They then use that as bait far more effectively. If you Google or YouTube “Heron catching fish with bait” you will be amazed at some of the video clips you are presented with. Anyone wishing to delve deeper can Google “The Wilson Bulletin” 106/1994 pp567/569 where you will find an excellent article dealing with this very subject.
The second of the species being dealt with here is the Water Dikkop or Thick Knee – Burhinus vermiculatus – which comes under the heading of Waders. It enjoys wide but patchy distribution in the Southern two thirds of Africa and can be found in singles, pairs or small groups. It is officially listed as of “Least concern”. However, in keeping with many of its compatriots, habitat loss is one of the factors leading to a general decline. It is very vocal in flight with a piercing call which, once identified, you are not likely to forget. It is crepuscular (dawn and dusk) in habit and even nocturnal in some places. We often see them sitting in the middle of the tracks when on a night drive in the Park.
Their diet is in keeping with many other wader species and tends to be broadly based rather than specific. This is, of course, a distinct advantage in the event of a shortage of one or more of its chosen prey species. Insects, crustaceans, amphibians, molluscs and fish are all taken. It tends to breed just before the rains and its nest is a simple scrape in the sand and pebbles where it lays up to 3 eggs. If it guesses wrongly, and the rains come early, it is often in danger of the nest being swamped. Another of its survival strategies, in certain areas, is to breed close to nesting crocodiles. This way it gets free protection from Monitors and the like that would relish nothing more than Dikkop eggs for breakfast. The two shown in the accompanying image, that are trying their best to look like Tyrannosaurus rex, didn’t have the benefit of that kind of protection. Hence they are having to fight their own battles (if you look carefully you will see the Nile Monitor blending into the grass in the foreground).
Both the above species are regularly seen on our Insect Photography Walks along the riverside.