6. Hadada Ibis The sound of this bird – a loud, penetrating and panicky-sounding ‘ha-da-da’ – is heard over most of sub-Saharan Africa, with the exceptions of Botswana, Namibia, the northern part of Kenya and Zimbabwe. It is more or less the aural signature of Johannesburg, especially at dawn and dusk, as anyone who has spent time there can attest. That strong and down-curved bill is perfect for digging worms out of marshy areas and suburban lawns: but it also works on rubbish dumps. It is a rather dull looking bird at a distance, though at close range even the brown is subtly patterned and variegated; you can see a red ‘culmen’ or upper part of its bill and a striking sheen of greenish-purple gloss or ‘iridescence’ on its wings. Iridescence, which many birds have, is not itself a colour, an actual pigment, at all: it is the effect of light passing through the translucent keratin of birds’ feathers, which acts as a prism. What we see as colour, then, changes depending on the angle of light that strikes the bird and is reflected into our eyes: the Hadada Ibis is not really ‘greenish-purple’ at all. Birds of AFRICAMA House 16 Birds of AFRICAMA House 17