oxpecker, common name for an African starling of the genus Buphagus. Also known as tickbirds, oxpeckers have very short legs and sharp claws, which aid them in perching on the backs of large mammals, both wild and domesticated. The animal host pays no heed to them, and only the elephant seems not to tolerate them. Oxpeckers use their broad, thick, laterally flattened beaks to pick at and feed on skin parasites such as ticks and embedded larvae. They also pick at scabs, often opening and enlarging wounds, and probably obtain their main nourishment from the blood from these wounds rather than from the ticks. Although these birds are valuable from the standpoint of ridding domesticated animals of ticks, they also feed on tick-free game and become debilitating parasites themselves. Nevertheless, they protect wild game from danger by setting up rattling cries, which alert the animals to the presence of predators. There are two species of oxpeckers, both about 9 in. (23 cm) long, with brown plumage and lacking distinctive markings. The slightly larger yellow-billed oxpecker (B. africanus), found from Senegal to Ethiopia and E South Africa, has a yellow, red-tipped bill, while that of the purely African red-billed oxpecker (B. erythrorhychus) is totally red. Oxpeckers are so highly adapted to life on their hosts that even courtship behavior and copulation occur upon the host animal's back. The hair of the animal is used to line the bird's nest, built usually in a tree by the yellow-billed oxpecker or a rock-hole by the red-billed. Females lay three to five white to pale blue, brown-spotted eggs per clutch. Oxpeckers are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Sturnidae.

The oxpecker consists of two species of bird which make up the family Buphagidae; some ornithologists regard them as a subfamily Buphaginae within the starling family Sturnidae but they appear to be quite distinct (see e.g. Zuccon et al. 2006). Oxpeckers are endemic to sub-Saharan African savannah.

According to the more recent studies of Muscicapoidea phylogeny (Cibois & Cracraft 2004, Zuccon et al. 2006), the oxpeckers are an ancient line related to Mimidae (mockingbirds and thrashers) and starlings but not particularly close to either. Considering the known biogeography of these groups, the most plausible explanation seems that the oxpecker lineage originated in Eastern or Southeastern Asia like the other two (Zuccon et al. 2006). This would make the two species of Buphagus something like living fossils, and elegantly demonstrates that such remnants of past evolution can possess striking and unique autapomorphic adaptations.

Species

• Red-billed Oxpecker, Buphagus erythrorhynchus of east Africa and Asia.
• Yellow-billed Oxpecker, Buphagus africanus of most of sub-saharan Africa.

Biology

Their plumage is light brown, and the species can be distinguished by bill-colour. They nest in holes, often in walls, lined with hair plucked from livestock and lay 2-3 eggs.

Oxpeckers are medium-sized starlings with strong feet. Their flight is strong and direct, and they are fairly gregarious. Their preferred habitat is open country, and they eat insects. Both the English and scientific names arise from their habit of perching on large mammals (both wild and domesticated) such as cattle or rhinoceroses, and eating ticks, botfly larvae, and other parasites which lodge in mammalian skin and must be dug out. This symbiotic relationship is believed to be mutualistic.

References

• (2004). Assessing the passerine 'tapestry': phylogenetic relationships of the Muscicapoidea inferred from nuclear DNA sequences. Molecular Phylogenetics and Evolution 32(1): 264–273. (HTML)
• (2006): Nuclear and mitochondrial sequence data reveal the major lineages of starlings, mynas and related taxa. Molecular Phylogenetics and Evolution 41(2): 333-344. (HTML abstract)