Nxai Pan's rich avifauna comprises a mixture of grassland, acacia scrub and mopane woodland birds, with a total of 217 species recorded in Hugh Chittenden's Top Birding Spots in Southern Africa (see Further Reading). Each habitat has its own typical residents.

Grassland birds include ant-eating chat, white-browed sparrow weaver, capped wheatear and pale-chanting goshawk. White-browed robin, pied babbler and chinspot batis are found in the acacia scrub. Red-billed hornbill, red-billed francolin and barred owl prefer the mopane.

The distinction between adjacent habitats is reflected in the parallel distributions of similar species. For example, double-banded coursers and white-quilled korhaans – both Kalahari specialists – occur only on the open grasslands, while bronze-winged coursers and red-crested korhaans, their close relatives, stick to the surrounding woodlands.

Resident raptors, such as bateleur, martial eagle, tawny eagle and brown snake eagle, are joined in summer by an influx of migrants, including steppe buzzard, western red-footed kestrel and yellow-billed kite. Raptor watching can be superb at this time, with more unusual species such as lesser-spotted eagle and hobby sometimes joining the throng at termite emergences.

Kori bustards, secretary birds and (in summer) white storks hunt the grasslands, and after good rains wattled cranes sometimes appear on the flashes. In spring the air resounds to the breeding displays of larks, including sabota, rufous-naped, red-capped, fawn-coloured, dusky and clapper. During summer the game herds are a focus of bird activity, with carmine and blue-cheeked bee-eaters hawking insects around the feet of springbok and zebra, red-billed and yellow-billed oxpeckers hitching rides on giraffes, and white-backed and lappet-faced vultures dropping from the sky onto carcasses.

Away from the pans, the campsites are a good place to search out the smaller passerines: violet-eared, black-cheeked and blue waxbills occur in the sandy acacia scrub together with melba and scaly-feathered finches, while shaft-tailed and paradise whydahs – brood parasites on waxbills – dash about in extravagant breeding finery. Baobabs are always worth checking, since they often provide roosting or nesting sites for rollers, hornbills and various owls.

Brood parasites

Cuckoos are not the only cheats of the bird world. Whydahs (Viduidae) are also brood parasites that lay their eggs in other birds' nests. Like cuckoos, each species of whydah exploits a specific host, and all of them choose waxbills (Estrildidae). However, unlike cuckoos, whydahs do not evict the eggs or nestlings of their host, so young whydahs grow up alongside their step-siblings, not instead of them.

To enhance the deception, a whydah's eggs – and there are usually two of them – perfectly mimic the colour of its host's clutch, and, once hatched, the whydah nestlings have exactly the right arrangements of gape spots inside their bills to dupe their step-parents into feeding them. A male whydah can even mimic the song of its host to distract it from the nest while the female goes about her devious business undisturbed. Breeding male whydahs are lively, conspicuous birds, who flaunt extravagant tail plumes in dancing display flights – though outside the breeding season they are indistinguishable from the drab females.

Three species of whydah occur in the pans region, of which the most typical is the shaft-tailed whydah (Vidua regia), easily recognised by the long thin tail-plumes of a breeding male, each tipped with a pennant. This species frequents sandy clearings in acacia thickets, often in association with its host, the violet-eared waxbill, and apparently without any animosity between them. The other two species are the pin-tailed whydah (Vidua macroura), which parasitises the common waxbill and prefers well-watered areas, and the paradise whydah (Vidua paradisaea), which parasitizes the melba finch and is a common bird of acacia savannah.