Topic : Rare Birds
Article 28 31 march 2007
Because of its nocturnal habits and secretive and elusive nature, White-backed Night-Heron Gorsachius leuconotus is one of the more difficult birds to see in Africa. In South Africa it could be considered to be among the 30 most difficult land birds to see though they are not as rare as records would suggest. Without a stakeout, your best chances of seeing this bird, is probably on a canoe in the warmer regions where there are some quiet backwaters with low overhanging branches. This is how I first found this unusual species on the Umhlanga Rocks Lagoon (just north of Durban) when I was about 15 yrs old.
Their first choice of habitat would be slow-flowing perennial rivers and streams with low overhanging vegetation. Quiet undisturbed riparian bush on the edge of lakes, dams and marshes is also very suitable but the important factor is daytime (roosting) disturbance – this they will not tolerate for long. To avoid detection they sometimes adopt a bittern posture with the bill pointing skywards and if they feel the need to move, will invariably run along the branches or ground in preference to taking flight. Because they are a strictly nocturnal (sometimes partly crepuscular) they search out areas of least diurnal disturbance and it’s in these dark protected overhanging vegetation sites that they will breed. At the nest site I photographed at, the birds (with chicks at the time) only left the nearby branches to go off feeding in the evening when it almost too dark to see.
Their nests are typically heron-like twig platforms, but instead of them being placed on outer exposed branches, this shy and secretive species conceals its nest under a shaded branch where it is more-or-less out of sight from both land and water. The chicks are initially covered with cream coloured down and this is replaced by brown-grey feathering till they fledge. On both nights that I photographed at a nest, I started watch before dark from within a nearby hide and remained there with food and water till about 01h00 in the morning (approx 7 hr spells). On each evening only 4 deliveries were made to the 3 chicks, i.e. about one delivery every one and a half hours!
The prey items were small and regurgitated into the chicks open gapes, so, disappointingly, food items were not identified. The chicks leave the nest when they are between two and three weeks old (long before they can fly), and seek refuge in the shaded upper branches of nearby foliage.
White-backed Night-Herons were undoubtedly far more common before the arrival of humans in the region and particularly before riparian bush became a target for cultivation. Conservation of what remains of river fringing habitats will secure the future of this species in southern Africa and any custodians of natural well wooded riverine fringes would do well to preserve this now rare commodity in the region. This species is regarded as a Vulnerable Red Data species in southern Africa.