Wilkinson's World

The Black-headed heron is very slightly smaller than the Grey heron, with a length of 94 cm and a wingspan approaching one and a half metres.  It is largely grey in colour, with a black crown and hind neck; legs and feet are black and the yellow eyes become red during the breeding season.  The sexes are alike in both size and plumage.

In flight, the Black-headed heron has a slow wingbeat, and, like all the herons, retracts its neck.  The white and grey under wings are conspicuous and easily distinguish it from the Grey heron which has all grey under wings.

Black-headed herons feed mainly in shallow water, but will also feed away from the water, in open grasslands and cultivated fields.  It feeds mainly on invertebrates, small mammals and reptiles, and sometimes on small birds.  Their call is a very loud “kwaak“.

Black-headed herons are monogamous and usually nest colonially in heronries with various other wading birds.  They build a large platform nest of sticks that may be situated in the reeds surrounding a body of water, but is more usually placed in a tree over the water.  The female lays a clutch of two to four pale green or bluish eggs that hatch after an incubation period of about 25 days.

The scientific binomial for the Black-headed heron is Ardea melanocephala; Ardea from the Latin for a heron and melanocephala from the Greek for black-headed.  Thus we have a Black-headed heron which is quite sensible, really.

 

We positioned ourselves below the nest, which was about three metres above the ground in a large Camel thorn tree (Acacia erioloba) and waited.  Many of the Sociable weavers flitted to-and-fro, arriving at the nest with insects tightly clasped in their bills and perching nearby, uttering rather sad little chirps as they looked on.  Watching the body of the snake we could clearly see bulges moving down its length as it swallowed the young birds that it found in the nest.  (As the adult birds were bringing food to the nest, we assumed that these were young birds being devoured rather than eggs.)

After a few minutes the snake withdrew its head and upper body from the nesting chamber in which it had been feeding, presumably having exhausted the food supply there, and moved quite cautiously to an adjacent chamber.  As it was on the underside of the nest, it kept itself firmly anchored in one of the chambers with its lower body as it moved, its head and upper-body suspended below the nest without support.

We were surprised that the little weavers made no attempt to mob the snake and although they were clearly agitated by its presence, they kept their distance and looked on.  It was quite sad to see the birds returning with food for the chicks, that had themselves become food during the interim – for the cobra.  The nest was obviously home to many young birds, and some of the adults entered chambers quite close to those being visited by the cobra, to feed chicks that had survived thus far.  We wondered how long it would be before the cobra made its way to those chambers….

After we had been watching the snake for the best part of an hour, during much of which very little of its body was visible, it withdrew completely into one of the chambers and didn’t emerge for the next ten minutes.  Perhaps it was sated for the moment and had withdrawn to rest.

We realized that many of the nests that we had seen over the years were probably being raided by snakes even as we looked on, because the presence of snakes is really quite difficult to see unless you happen to be passing just when they are moving from one chamber to the other.  While they are busy feeding or resting, they are, to the casual observer, practically invisible.  As so often happens with events in the bushveld, it is all a matter of timing!  And the moral of the story – be careful about putting your hands in nests.

Although the Cape turtle-dove has a range that embraces most of the southern African region and well beyond, it is, in spite of its name, absent from the winter rainfall  area of the western Cape of South Africa.  It is a medium sized dove, around 27 cm in length, and is grey overall, with a black collar and the white under-tail feathers are conspicuous when the bird is in flight.  Legs and feet are purple and the eyes are dark brown to black.  The sexes are similar in plumage and the males are slightly larger than the females.

Generally absent from forested areas, the Cape turtle dove is very common in woodlands, farmlands and in parks and gardens where it has adapted well to the presence of humans.  Although generally found singly or in small groups, large flocks may form at good water sources.  At watering points in the Kgalagadi we have seen flocks that must have numbered in the hundreds of birds (and witnessed one of them being struck from the air by an incredibly fast-moving Lanner falcon).  They feed mainly on seeds, but also on fruit, earthworms, termites and insects.

The Cape turtle dove is monogamous and builds a flimsy platform nest of twigs and grass, usually three to four metres above the ground in a tree.  The female lays a clutch of two or three creamy-white eggs that hatch after an incubation period of about 15 days.

The scientific name of the Cape turtle dove is Streptopelia capicola; Streptopelia from the Greek for a collared dove and capicola from the Latin meaning an inhabitant of the Cape (of Good Hope).  Thus we have a collared dove from the Cape.  Can’t say fairer than that.