Zoological investigations VII

That’s right, I said “oxpecker,” and no, I am not just gearing you up for Valentine’s Day. Folks, I am talking about birds — vampiristic birds! What a way to get back into the swing of things, while we wake up and go home, never seeing the sun, since we are stuck behind four walls that are most probably very insufficiently punctured by windows.

Speaking of puncture, the oxpeckers belong to the family Buphagidae, and are considered distant evolutionary relatives of the mockingbirds, thrashers and starlings. There are two species, red-billed and yellow-billed. Native to Africa, they make their living primarily by hitching rides and feeding on large, hoofed mammals such as wildebeest, impala, giraffe, rhinoceros, water buffalo and others. Oxpeckers feed heavily on parasites living off mammalian blood and tissues. They especially enjoy ticks, but will also eat lice, mites, fleas, small insects and other organisms attempting to lodge within open wounds, and also consume dead skin cells. This relationship was once thought to be symbiotic, with mammals benefiting by removal of the external parasites and birds benefiting by a nutritious (albeit disgusting) meal, but that viewpoint is no longer so certain. Instead it may be that the oxpeckers are themselves a type of parasite. There are many observations of these birds actively feeding on the blood of their host mammals. Observations have been made of oxpeckers actively keeping wounds open, of using their bill to exert pressure around wounds to increase blood flow, and of drinking blood from wounds made by ticks without consuming the ticks themselves. Observations of the birds initiating wounds themselves are apparently some combination of absent, rare and/or unreliable.

While some evidence exists to show that oxpeckers can actually weaken and stress their mammalian hosts by keeping wounds open, they also keep wounds free of bacteria and other infectious agents, so while they may be riddled with open sores, they are at least clean sores. Most animals tolerate the oxpeckers, and many have learned to respond to oxpecker alarm calls, which the birds make when they spot predators, and thus gain protection in the form of an early-warning system. Yet not all of our hoofed friends appreciate these offers; elephants and some species of antelope actively and effectively avoid, resist and remove the oxpeckers from their bodies.

Oxpeckers certainly rely heavily on large African mammals. They feed, sleep, court and even mate on the backs of their hosts, and use the hair and dung of their hosts to build nests. They also eat ear-wax.