Our photos show elephants digging for water and minerals at Nehimba Seeps in Hwange – but look closely and notice the yellow-billed oxpeckers. These birds feed on ectoparasites such as ticks on the host animal. Observers of the Hwange ecosystem say oxpeckers are not often seen on elephants, favoring other softer-skinned hosts such as buffalo, zebra, giraffe, so this scene was a little unusual. Now notice that the oxpeckers are showing a clear preference for feeding on the baby elephant. The birds may prefer individual hosts with higher parasite density – more ticks – and it is possible that the baby elephant is carrying a higher load of ticks. This, in itself, may reflect the poor body condition of the baby in the testing time of Hwange’s long dry season. Or just that the youngster cannot flick off the annoying birds as effectively with a trunk as can adults! But oxpeckers are not quite the helpful caregivers we might like to think – oxpeckers have been observed to open new wounds and enhance existing ones in order to drink the blood of their perches – look closely again to see the wound on the baby elephant’s back.
And here’s another oxpecker conundrum for armchair enthusiasts out there – of the two species of oxpecker in Africa, the yellow-billed is much more common than the red-billed in Hwange – why? This does not hold true for the distribution of the birds in nations around us; the opposite is the case in Kruger, for example. The red-billed has a more slender bill and the yellow-billed a broader bill, but preference for tough or softer-skinned hosts is not clear-cut between the two species. Certainly, the red-billed favors rhinos – and rhinos had not been seen in our area for some 20 years before Imvelo reintroduced white rhinos last year. (Our photo shows the red-billed birds on hippo in Hwange.) One suggestion for causes affecting oxpecker distribution is a preference for certain species of tick which may also have variable distribution – more research is needed! This all just shows how much we do not know about the wild world around us.