Oxpecker
Encyclopedia
The oxpeckers are 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. Oxpeckers are endemic to the savanna
of Sub-Saharan Africa
. Both the English
and scientific names arise from their habit of perching on large mammal
s (both wild and domesticated) such as cattle
or rhinoceros
es, and eating tick
s, botfly
larva
e, and other parasites.
According to the more recent studies of Muscicapoidea phylogeny, 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. This would make the two species of Buphagus something like living fossil
s, and elegantly demonstrates that such remnants of past evolution
can possess striking and unique autapomorphic adaptations.
s. They are absent from the driest desert
s and the rainforest
s. Their distribution is restricted by the presence of their preferred prey, specific species of tick
s, and the animal hosts of those ticks. Over much of East Africa the two species are sympatric (have overlapping distribution) and may even occur on the same host animal. The nature of the interactions between the two species is unknown.
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Oxpeckers feed exclusively on the backs of large mammals. Certain species are seemingly preferred, whereas others, like the Lichtenstein's hartebeest
or Topi
are generally avoided. Smaller antelope such as lechwe
, duiker
s and reedbuck
are also 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.
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. 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. 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. 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. Some oxpecker hosts are intolerant of their presence. 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.
is between two to three eggs
, but the Red-billed Oxpecker
may lay up to five eggs.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
which make up the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Buphagidae. Some ornithologists regard them as a subfamily Buphaginae within the starling
Starling
Starlings are small to medium-sized passerine birds in the family Sturnidae. The name "Sturnidae" comes from the Latin word for starling, sturnus. Many Asian species, particularly the larger ones, are called mynas, and many African species are known as glossy starlings because of their iridescent...
family Sturnidae but they appear to be quite distinct. Oxpeckers are endemic to the savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
of Sub-Saharan Africa
Sub-Saharan Africa
Sub-Saharan Africa as a geographical term refers to the area of the African continent which lies south of the Sahara. A political definition of Sub-Saharan Africa, instead, covers all African countries which are fully or partially located south of the Sahara...
. Both the English
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
and scientific names arise from their habit of perching on large mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s (both wild and domesticated) such as cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
or rhinoceros
Rhinoceros
Rhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
es, and eating tick
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
s, botfly
Botfly
A botfly is any fly in the family Oestridae, which includes all the members of the former families Cuterebridae, Gasterophilidae, and Hypodermatidae. It is the only family of flies whose larvae live as obligate parasites within the bodies of mammals, with the exception of a few screwworm flies in...
larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e, and other parasites.
According to the more recent studies of Muscicapoidea phylogeny, the oxpeckers are an ancient line related to Mimidae (mockingbirds and thrashers) and starlings but not particularly close to either. Considering the known biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
of these groups, the most plausible explanation seems that the oxpecker lineage originated in Eastern or Southeastern Asia like the other two. This would make the two species of Buphagus something like living fossil
Living fossil
Living fossil is an informal term for any living species which appears similar to a species otherwise only known from fossils and which has no close living relatives, or a group of organisms which have long fossil records...
s, and elegantly demonstrates that such remnants of past evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
can possess striking and unique autapomorphic adaptations.
Distribution and habitat
The oxpeckers are endemic to sub-Saharan Africa, where they occur in most open habitatHabitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s. They are absent from the driest desert
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
s and the rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s. Their distribution is restricted by the presence of their preferred prey, specific species of tick
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
s, and the animal hosts of those ticks. Over much of East Africa the two species are sympatric (have overlapping distribution) and may even occur on the same host animal. The nature of the interactions between the two species is unknown.
Diet and feeding
Lichtenstein's Hartebeest
Lichtenstein's Hartebeest is a savannah and floodplain dwelling antelope found in southern Central Africa. By some this species is classified as Sigmoceros lichtensteinii....
or Topi
Topi
The Tsessebe , is one of five subspecies in the binomial class D. lunatus. The other subspecies include Korrigum , Tiang , Coastal Topi , and Topi . Tesessebe are found primarily in Zambia, Namibia, Botswana, Zimbabwe, and South Africa...
are generally avoided. Smaller antelope such as lechwe
Lechwe
The Lechwe, or Southern Lechwe, is an antelope found in Botswana, Zambia, south-eastern Democratic Republic of the Congo, north-eastern Namibia, and eastern Angola, especially in the Okavango Delta, Kafue Flats and Bangweulu Swamps....
, duiker
Duiker
A duiker is any of about 21 small to medium-sized antelope species from the subfamily Cephalophinae native to Sub-Saharan Africa.Duikers are shy and elusive creatures with a fondness for dense cover; most are forest dwellers and even the species living in more open areas are quick to disappear...
s and reedbuck
Reedbuck
Reedbuck is a common name for African antelopes from the genus Redunca. These species are:* Southern Reedbuck, Redunca arundinum* Mountain Reedbuck, Redunca fulvorufula* Bohor Reedbuck, Redunca redunca...
are also avoided, the smallest regularly used species is the Impala
Impala
An impala is a medium-sized African antelope. The name impala comes from the Zulu language meaning "gazelle"...
, 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.
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. 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. 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. 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. Some oxpecker hosts are intolerant of their presence. 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.
Breeding
The breeding season of the oxpeckers, in at least one location, is linked to the rainy season, which affects the activity of their mammalian hosts and the tick loads of those hosts. Both courtship and copulation occur on their hosts as well. They nest in holes, usually in trees but sometimes in other types of cavity, including holes in walls. The nests are lined with grasses and also often with hair plucked from their hosts and even livestock such as sheep which are not usually used. The typical clutchClutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
is between two to three eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, but the Red-billed Oxpecker
Red-billed Oxpecker
The Red-billed Oxpecker, Buphagus erythrorhynchus, is a passerine bird in the starling and myna family Sturndidae; some ornithologists regard the oxpeckers to be in a family by themselves, the Buphagidae. It is native to the savannah of sub-Saharan Africa, from the Central African Republic east to...
may lay up to five eggs.
Species
- Red-billed OxpeckerRed-billed OxpeckerThe Red-billed Oxpecker, Buphagus erythrorhynchus, is a passerine bird in the starling and myna family Sturndidae; some ornithologists regard the oxpeckers to be in a family by themselves, the Buphagidae. It is native to the savannah of sub-Saharan Africa, from the Central African Republic east to...
, Buphagus erythrorhynchus of east Africa. - Yellow-billed OxpeckerYellow-billed OxpeckerThe Yellow-billed Oxpecker, Buphagus africanus, is a passerine bird in the starling and myna family Sturnidae; some ornithologists regard the Oxpeckers to be a separate family, the Buphagidae . It is native to the savannah of sub-Saharan Africa from Senegal east to Sudan...
, Buphagus africanus of most of sub-Saharan Africa.