The Largest, The Smallest And The Most Threatened Herons Of Namibia

30 Apr 2021

The big bird stands in the shallows motionless. It intently watches the water at its feet and waits patiently. Then, within a split-second, the long pointed beak lunges forward, water splashes and a large African sharptooth catfish is speared. The heron laboriously drags its catch ashore, shakes the thrashing fish off its beak, eyes it briefly and then grabs it by the head. Surely the delicate long neck cannot cope with this weight, you think, and surely prey of this size cannot be swallowed in one piece? But the Goliath Heron (Ardea goliath) raises its head, jerks its beak a few times and the fish disappears down the gullet. The bird stretches itself to its formidable height of 1.50 metres and resumes its scrutiny of the surroundings. It is the largest species of heron in Namibia and in fact the largest in the world. Its diet not only consists of fish of considerable size, but also of frogs, reptiles and small mammals.

There is a faint movement in the dense reeds. As soon as the Little Bittern feels being watched it points its bill vertically upwards and attentively looks around for the possible danger. It is able to look past the raised beak with both eyes. In this well-camouflaged spot in the dense plant growth it is difficult to discover the bird. The Little Bittern (Ixobrychus minutus) and the Dwarf Bittern (Ixobrychus sturmii) are the smallest species of heron in Namibia: the Little Bittern stands close to 36 cm tall and weighs 110 g, while the Dwarf Bittern is 30 cm tall and weighs 140 g. They feed mainly on frogs, small fish and aquatic insects.

The Slaty Egret (Egretta vinaceigula) and the Rufous-bellied Heron (Ardeola rufiventris) are classified as critically endangered in Namibia. The Slaty Egret is slate-grey, as the name suggests, with some rusty brown on the throat and front neck, while the Rufous-bellied Heron is grey-black with some rusty-brown on the belly and on the wings. The Slaty Egret is often confused with the Black Heron, but can be told apart by its yellow legs. Both species prefer tidal flats and marches where they forage in shallow water. Small fish make up the main diet of the Slaty Egret, but it also eats tadpoles, snails and insects. The Rufous-bellied Heron feeds on fish, frogs, insects and worms.

The largest heron as well as the smallest and the most threatened members of the heron family can be found at the Okavango, Kwando, Zambezi and Chobe rivers in north-eastern Namibia. The Goliath Heron, the Rufous-bellied Heron and the two bittern species also occur at the Kunene River in the northwest. In years with plentiful rains they move to other parts of the country, especially the bitterns, and breed at pans and similar small seasonal bodies of water which offer sufficient food for a limited period of time. I ringed Dwarf Bitterns at a pan on the farm Wiese between Rehoboth and Uhlenhorst and found nests there. A Dwarf Bittern was also caught in a net and ringed at the Kunene River’s mouth.

Author: Dirk Heinrich