Oxpecker

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Oxpeckers
Red-billed Oxpecker
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Suborder: Passeri
Family: Buphagidae
Lesson, 1828
Genus: Buphagus
Brisson, 1760
Species

Buphagus africanus
Buphagus erythrorhynchus

Redbilled Oxpeckers on a Rhinoceros
Yellow-billed Oxpeckers on an Ass

The oxpeckers are the two species of bird which make up the family Buphagidae.[1]

Oxpeckers are endemic to the savanna of Sub-Saharan Africa. Their names come 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.

According to the more recent studies of phylogeny,[1][2] the oxpeckers are an ancient line related to the Mimidae (mockingbirds, thrashers &c.) and starlings, but not particularly close to either.

Considering the known biogeography (distribution) of these groups, the most plausible explanation seems that the oxpecker lineage originated in Eastern or Southeastern Asia like the other two.[1] 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 adaptations.

Diet and feeding[change | change source]

Oxpeckers feed exclusively on the backs of large mammals. Certain species seem preferred, whereas others, like the Lichtenstein's hartebeest or Topi are generally avoided. The smallest regularly used species is the Impala, probably because of the heavy tick load and social nature of that species. In many parts of their range they now feed on cattle, but avoid camels. They feed on ectoparasites, particularly ticks, as well as insects infecting wounds and the flesh and blood of some wounds as well.[3]

Oxpecker/mammal interactions are the subject of some debate and ongoing research. They were originally thought to be an example of mutualism, but recent evidence suggests that oxpeckers may be parasites instead.[4] Oxpeckers do eat ticks, but often the ticks that have already fed on the ungulate host and there has been no proven statistically significant link between oxpecker presence and reduced ectoparasite load .[4] However one study of impalas found that impalas which were used by oxpeckers spent less time grooming themselves suggesting a reduction in parasite load. Oxpeckers have been observed to open new wounds and enhance existing ones in order to drink the blood of their perches .[5] Oxpeckers also feed on the earwax and dandruffs of mammals, although less is known about the benefits of this to the mammal, it is suspected that this is also a parasitic behaviour.[4] Some oxpecker hosts are intolerant of their presence.[5] Elephants and some antelope will actively dislodge the oxpeckers when they land. Other species tolerate oxpeckers while they search for ticks on the face, what one author described as "appears ... to be an uncomfortable and invasive process.[3]

References[change | change source]

  1. 1.0 1.1 1.2 Zuccon, Dario; Cibois, Anne; Pasquet, Eric & Ericson, Per G.P. (2006). "Nuclear and mitochondrial sequence data reveal the major lineages of starlings, mynas and related taxa". Molecular Phylogenetics and Evolution 41 (2): 333–344. doi:10.1016/j.ympev.2006.05.007 . PMID 16806992 .
  2. Cibois, A; Cracraft, J. (2004). "Assessing the passerine 'tapestry': phylogenetic relationships of the Muscicapoidea inferred from nuclear DNA sequences". Molecular Phylogenetics and Evolution 31 (1): 264–273. doi:10.1016/j.ympev.2003.12.002 . PMID 15186812 .
  3. 3.0 3.1 Craig, Adrian (2009). "Family Buphagidae (Oxpeckers)". In del Hoyo, Josep; Elliott, Andrew; Christie, David. Handbook of the Birds of the World. Volume 14, Bush-shrikes to Old World Sparrows. Barcelona: Lynx Edicions. pp. 642–653. ISBN 978-84-96553-50-7 . http://www.lynxeds.com/hbw/family-text/hbw-14-family-text-buphagidae-oxpeckers.
  4. 4.0 4.1 4.2 Weeks, P (2000). "Red-billed oxpeckers: vampires or tickbirds?" (PDF). Behavioral Ecology 11 (2): 154–160.
  5. 5.0 5.1 McElligott, A.G.; Maggini, I., Hunziker, L., and Konig, B. (2004). "Interactions Between Red-Billed Oxpeckers and Black Rhinos in Captivity". Zoo Biology 23: 347–354. doi:10.1002/zoo.20013 .