Oxpecker - Wikipedia
What kind of relationship? The bacteria feed off of the food we What kind of relationship? The oxpecker bird eats ticks living on the hippopotamus's back. Hippos have symbiotic relationships with several species — meaning both animals in the This can often be seen with oxpecker birds. Symbiotic Relationship funny cartoons from CartoonStock directory - the ' then they jumped off the hippo, they jumped on to me, and they've been there ever.
Not only do the birds help the animals limit parasites but they also warn the animals of danger by flying off screeching at danger. Recently, however, it has been discovered that Oxpeckers also pick at the wounds of animals, keeping them open and drinking the blood of the animals.
This is semi-parasitic behaviour and the debate is whether the Oxpecker is of benefit or harm to its' host. Personal observations tend to point toward the fact that the feeding on wounds and blood, although not uncommon, is not the norm and therefore the relationship is still of benefit to both species. The egret will feed on insects disturbed by the animal moving and pick parasites off the animal. The Buffalo is the most common mammal that shares a relationship with the egret.
Egrets will ride on the backs of Buffalo and can act as a warning system. Whilst based in the Okavango Delta in Botswana I witnessed a relationship between a Fish Eagle and Buffalo that brings up a few points of discussion.
On a few occasions I observed a Fish Eagle sitting on the back of a Buffalo and staring into the water. On no occasion did I observe it catching anything.
When I was first informed of this behaviour by one of my colleagues my initial thought was that it was and egret sitting on the buffalo. Nobody had seen this before. Each time I observed this the Buffalo was feeding far into the floodplain where the grass was long, hiding the water.
There was no way for the Eagle to see that far from its perch so it had to get a better vantage point. What had happened to get the eagle to hunt in an area it would normally avoid?
It must have been successful in the past to have repeated the action. Parasites In parasitic relationships one species benefits while the other one is harmed.
The classic example of this is the case of Cuckoos that lay their eggs in other birds' nests. The Cuckoo egg hatches first and the chick will eject the egg of the host species or, if the eggs of the host have hatched, will kill or eject the chicks.
A tentative date for the divergence of the Buphagidae, based on a molecular clock, is 22 million years ago, but there are at present no known fossils which could provide independent confirmation of the age of the group. The two extant species are clearly sister-taxa, and hybrids between them have been reported from Zimbabwe in free-living populations in which one species greatly outnumbers the other.
As with many other African birds, a plethora of subspecific taxa has been described, the great majority based on minor differences in size and plumage; most of these differences seem not to be biologically informative in terms of defining populations between which there is reduced gene flow. Thus, the common ancestor of the oxpeckers and the starlings would have exhibited some of the morphological traits described above, which have been cited previously as evidence of relationship.
In cladistic terms, however, these are shared primitive characters, and thus uninformative in comparison with derived features. In Africa, the savanna habitat has been the centre of evolution for a number of bird families, and also for the ungulates, so that there would have been a long association between the birds and the mammals.
Several modern starlings include ectoparasites in their diet, and have been seen to remove ticks Ixodoidea from both domestic and wild ungulates. In the case of the Red-winged Starling Onychognathus morio and the Pale-winged Starling Onychognathus nabouroupa regular grooming association with the klipspringer Oreotragus oreotragus has been recorded at several localities in Africa see pages Dietary specialists could well have evolved from such opportunistic generalists.
Morphological Aspects The plumage of oxpeckers is dull, lacking any of the iridescence displayed by the starlings, and there is no sexual dimorphism in coloration. Males of both species are, on average, slightly larger than the females, although considerable overlap in measurements exists. The tail is graduated, with the individual rectrices stiff and pointed, and it is used as a prop to support the bird in the posture of a woodpecker Picidae on a tree trunk.
Indeed, an observer at a Red-billed Oxpecker nest in a tree-hole reported that, when one young left the nest prematurely and fluttered to the ground below, the adults led it back to the nest by running up the trunk in a manner reminiscent of a woodpecker. The moult is very protracted, the Red-billed Oxpecker taking more than days to replace the primary remiges in South Africa.
As a consequence, some overlap between breeding activity and moulting will occur, although, with such a slow rate of moult, this is unlikely to be stressful for the birds. On the evidence of museum specimens, an extended moult period is likely to be typical for all populations of both oxpecker species. Although the two species differ in bill shape, the Yellow-billed Oxpecker Buphagus africanus having a flatter and deeper lower mandible than that of its congener, there is no clear evidence that this is associated with different feeding methods.
Nestlings of both species have a greenish-yellow bill colour, which changes to dark brown when they fledge, and they have a yellow wattle around the eye, which darkens to dull brown in the immature. In the case of the Red-billed Oxpecker, the eye wattle changes again, to yellow, in the adult, although this is not so with the Yellow-billed Oxpecker. Juveniles younger than 60 days of age still have a yellow bill, while the bill of the young Red-billed Oxpecker becomes dark brown from about days.
Adult bill colour is acquired at about seven months by the Red-billed Oxpecker, and certainly within the first year of life by the Yellow-billed Oxpecker.
Further, juveniles have a dark brown iris, which, in the case of the Red-billed Oxpecker, starts to turn yellow at about four months and changes to yellowish-red by the time the birds are months old. The timing of this iris-colour change has not been recorded for the other species, and the morphological basis of the eye coloration is not known. The possible signal value of these changes in eye and bill colours has yet to be studied.
Chapin reported that the eye colour of a captive oxpecker varied, and he speculated that it might be dependent on blood flow, in which case spontaneous changes in the intensity of eye coloration would be possible. Lowe commented in a footnote that his dissection of the jaw musculature of Buphagus suggested that the latter was a starling in the broad sense, but that the maxillo-palatine and vomer bones in the skull differed sufficiently from those of other starlings to imply that it should be placed in a separate subfamily.
Beecher also examined the jaw muscles of the starlings, and noted that, in the Red-billed Oxpecker, both the protractor of the quadrate and the pterygoid and palatine muscles were enlarged, a development typical of the woodpeckers and apparently associated with the buffering of the brain against the shocks resulting from blows delivered by the bill. In other respects, he found the jaw musculature to be similar to that of the primitive starling condition, as opposed to the derived state found in those starling species that are specialized for probing.
Oxpeckers spend most of the day perched on the top or side of large mammals see General Habitsand the buphagid leg musculature reflects this fact. Studies of the hind-limb musculature of the oxpeckers showed that the basic arrangement of the leg muscles resembled that of true starlings, the only differences affecting muscles which increased the grasping power of the feet.
The legs are relatively short compared with those of either perching or ground-dwelling birds of similar body weight. The claws of oxpeckers exhibit the structure and curvature typical of climbing birds such as woodpeckers, treecreepers Certhiidae and nuthatches Sittidaewhereas the Common Starling Sturnus vulgaris has the claws of a typical perching bird.
In contrast to members of the starling family, the oxpeckers' hind claw is shorter than the claw on the middle toe, the reverse of the pattern found in perching birds. Oxpeckers also have a very fine constricted tip on the claws, which may be an adaptation for penetrating the substrate at the tip while maintaining claw strength along the rest of its length.
One collector commented that, if a freshly killed oxpecker was placed on the skin of an ox, the feet and claws immediately grasped the substrate, and it was difficult to disengage them. Habitat Both members of this family are savanna species, being absent from deserts and from closed evergreen forest. Their habitat choice, however, is further constrained by preferences for particular host mammals, and for the main tick species on which they feed.
The favoured ticks are limited by humidity, and evidently cannot survive in some open grassland or scrub habitats; these regions would also lack suitable nesting sites for the oxpeckers.
In South Africa, C. Stutterheim showed that the historical records of the Red-billed Oxpecker coincided closely with the distribution of the two commonest tick species, namely Boophilus decoloratus and Rhipicephalus appendiculatus, recorded in the stomach contents of wild birds, and favoured in feeding trials with two captive individuals.
Both of these tick species, however, extended into the winter-rainfall region of the southern coast, whereas the western limit for the Red-billed Oxpecker was at the boundary of the summer-rainfall region. The Yellow-billed Oxpecker, too, feeds extensively on R. The ticks are again a good predictor of this oxpecker's distribution in north-eastern South Africa, but this buphagid seems never to have occurred so far south as does its congener.
Through much of eastern Africa the two species are extensively sympatric, and there is no obvious separation between them in habitat selection; both have been recorded at up to m in Kenya, with some indication that Yellow-billed Oxpeckers are more often found above m and Red-billed Oxpeckers at lower altitudes. For other regions of Africa, data on tick distribution are too incomplete for any correlation with the distribution of the birds to be assessed. Considerable overlap in host choice between the two oxpecker species is evident, and the two can sometimes be seen side by side on the same mammal.
There have been no systematic observations of their interactions in this situation, although there is little indication that either of the two buphagid species is influenced in its choice of host animal by the presence of the other species.
Under captive conditions, Yellow-billed Oxpeckers were constantly dominant over Red-billed Oxpeckers, although there were relatively few direct confrontations. Some mammal species appear to be avoided.
Savanna elephants Loxodonta africana do not tolerate oxpeckers and quickly chase them off. A few reports from Zimbabwe of oxpeckers on elephants were during a severe drought, when the elephants were in very poor physical condition and appeared totally indifferent to the presence of the birds.
It has been suggested by several observers that elephants are sensitive to the sharp claws of oxpeckers, one ornithologist describing them as being thin-skinned animals with a trunk. On the other hand, through much of western Africa, elephants are commonly seen with Piapiacs Ptilostomus afera corvid having much blunter claws and a different foot structure, perched on them. Bushbucks Tragelaphus scriptus and common waterbucks Kobus ellipsyprimnus have been seen actively to dislodge oxpeckers which landed on them; the lechwe Kobus leche and the puku Kobus vardonii are not exploited by the birds, either, nor are southern reedbucks Redunca arundinum.
The impala Aepyceros melampus seems to be the only smaller antelope regularly patronized by oxpeckers, whereas there are no reports for any of the duikers Cephalophinae being so used.
This may be explained by the fact that impalas are found in bushy habitat, which leads to a high load of immature ticks, and live in a herd structure, which provides a number of individual hosts in close proximity. In Zambia, the large-bodied Lichtenstein's hartebeest Alcelaphus lichtensteinii seemed to be avoided by oxpeckers, although it was reported as a host for Yellow-billed Oxpeckers in Mali, while the tsessebe, or topi Damaliscus lunatusis also utilized much less frequently than would be expected.The Oxpeckers role in the Animal Kingdom
Many observers have provided lists of the host mammals on which oxpeckers have been sighted. In current national parks these may often be biased by the availability and relative abundance of particular game species, and this may account for some of the apparent regional differences observed. Nevertheless, there is a general consensus concerning the ungulates which are utilized most frequently under natural conditions. These are the African buffalo Syncerus cafferwhite rhinoceros Ceratotherium simumblack rhinoceros Diceros bicornisgiraffe Giraffa camelopardalishippopotamus Hippopotamus amphibiusgreater kudu Tragelaphus strepsiceroseland Taurotragus oryxroan antelope Hippotragus equinussable antelope Hippotragus nigerBurchell's zebra Equus burchelliiblue wildebeest Connochaetes taurinusimpala, and desert warthog Phacochoerus aethiopicus.
Cattle arrived in north Africa at least years ago, and there were certainly herds of domestic animals north of the equator for thousands of years, although the herdsmen are thought to have moved southwards only some years ago, reaching the current southern limit of the oxpeckers' distribution about years before the present.
Today, cattle are the primary hosts of oxpeckers in many regions. Archer noted that oxpeckers were rare in Somalia not only because of the general absence of wild ungulate hosts, but also because of the widespread replacement of cattle and donkeys by camels Cameluswhich were evidently not favoured by the buphagids. Single-humped domesticated camels, known as dromedaries Camelus dromedariusare thought to have reached Africa from Asia only within the last years.
What is the relationship between oxpecker bird and hippo?
Nevertheless, other observers do report instances of oxpeckers feeding from camels. Horses will usually not tolerate oxpeckers according to some observers, but others have reported having recorded these birds as perching on horses, often feeding at wounds, as well as on donkeys and mules. Oxpeckers occasionally perch on goats or sheep, and sometimes on domestic pigs. General Habits Since oxpeckers spend most of their days perched on the host mammals, relatively few activities take place away from the host.
Nevertheless, oxpeckers have been observed to dust-bathe, as well as indulging in conventional bathing in water. The birds will leave their mammalian hosts briefly and fly to water-holes in order to drink or bathe, but more often they are passengers when the mammals go to drink. Sometimes the oxpeckers simply run down the animal's leg to reach the water, and take a few sips without actually "detaching" themselves from the mammal. After bathing, they preen the wet plumage while perched on the host.
In addition, captive Red-billed Oxpeckers adopted typical sun-bathing postures while perched on a wall within their enclosure, and they were also photographed while sunning, with the wings and tail spread out, on the back of a rhinoceros.
Symbiotic relationship between Oxpecker bird an hippopotamus by Ben Williams on Prezi
When moving about on the host mammal, oxpeckers generally hop, moving both hind limbs simultaneously, but when stalking flies or during courtship they will also "walk", moving the limbs alternately. They seem invariably to hold the head held up, and they move forwards or sideways and even backwards, but seldom hang suspended underneath the animal. When defecating, oxpeckers lean forward, raise the tail, and generally spray the excrement well away from the host's body.
Throughout their range, Red-billed Oxpeckers leave the host animals in the evening and fly off to roost in small groups, or as large flocks from several sites, in trees or reedbeds. These roost-sites may be shared with Lamprotornis starlings, and in some areas even buildings are used for roosting. Similar behaviour has been reported for Yellow-billed Oxpeckers in Nigeria, where the birds roosted in trees, but in Zambia this species was seen to sleep on buffaloes at night, in Zimbabwe observers reported the oxpeckers as sleeping while perched on kudus, elands and sable antelopes, and in Uganda a group was found to be sleeping on a giraffe.
HBW 14 - Family text: Buphagidae (Oxpeckers)
There is one report from Zambia of Red-billed Oxpeckers on buffaloes at night. How widespread this behaviour is remains unclear, and it is not known which local conditions may determine the birds' choice of sleeping place. Molecular techniques were employed in order to determine the sex of Red-billed Oxpeckers in Zimbabwe.
The results revealed that the sex ratio among regular group-members was balanced, but that the composition of non-breeding social groups was quite fluid over time. Although the overall sex ratio was 52 males to females, this appeared to be an artefact of the restricted sampling area and the apparent greater mobility of females in all age-classes.
Voice Oxpeckers hardly rate a mention as songsters, and the vocalizations which have attracted most attention are the alarm calls given while the oxpeckers are perched on their mammalian hosts, and the flight calls emitted by the birds when startled or on their way to or from roost-sites. These are the diagnostic calls for human observers in the field. Neweklowsky, however, described two song types for the Red-billed Oxpecker in the Zurich Zoo, in Switzerland.
One consisted of a string of soft calls, interspersed with trills and whistles, which were uttered by both male and female of a pair when they were temporarily separated; and the second type was a series of drawn-out whistling notes used in courtship, and seemingly given by the male alone. Clearly, we are most likely to discover the full repertoire of oxpecker vocalizations from observations of individuals in captivity, where a close approach is possible, and the host animals are also habituated to the presence of humans.
Currently, more attention is being paid to the songs produced by female birds, and it is evident that, with many passerine species, the females do sing, often in the same contexts of territorial defence or courtship as those which elicit song from the males. Future studies of oxpecker vocalizations should, therefore, focus on individually marked birds of known sex.
Food and Feeding The main food item of the Buphagidae is ticks, with a clear preference apparent for particular species and also for certain stages in the ticks' life-cycle.
The Red-billed Oxpecker, especially, feeds primarily on the immature stages of ticks. Lice Anoplurafly larvae Diptera and leeches Hirudinea are also removed from the host's body surface, while flying insects such as dipterans, particularly horseflies Tabanidae and blackflies Simuliidaeare caught in the air. As engorged ticks are in essence small bags of blood, the oxpeckers will also feed directly on blood from wounds, and sometimes on other body fluids such as mucus from the nose or eyes, and even on ear wax, which would seem to have little nutritive value.
There seem not to be any major differences in food preferences between the two species, except that, on the basis of comparative studies of a small number of captive individuals, Yellow-billed Oxpeckers may catch more biting insects and take larger ticks, such as engorged females of Amblyomma hebraeum, than do Red-billed Oxpeckers.
Oxpeckers remove ectoparasites from their mammalian hosts by two different techniques. One of these involves simple pecking and plucking with the tip of the bill, whereas in the other method, known as "scissoring", the bill is laid sideways against the skin and is then opened and closed, as with a pair of scissors. The former approach depends on visual location of the prey, while in the latter technique the prey is detected by touch.
The feeding style utilized is correlated with the hair structure of the host, with scissoring not employed on nearly hairless animals, such as rhinoceroses or hippopotamuses, except at wounds or when collecting mucus at the nasal openings.
The highest frequency of scissoring is observed when the buphagid is on the longest-haired hosts, such as the kudu and the roan and sable antelopes. The head and ear regions are in many cases the areas where the birds spend the majority of their foraging time, and regular hosts are often most accommodating in allowing what appears to the human observer to be an uncomfortable and invasive process. Studies of the impala's interactions with oxpeckers indicate that the antelope grooms less often when visited by the birds, suggesting that it does benefit from the association.
In this case, the oxpeckers clearly focus their attention on areas which the impalas are not able to reach effectively by their own means, and where the highest concentrations of ticks are likely to be found. Two of the common tick prey species, Amblyomma hebraeum and Boophilus decoloratus, have also been recorded as ectoparasites of both adult and nestling Red-billed Oxpeckers.
Since these ticks were found much more frequently on the nestlings, it is possible that they represent live food which had escaped after having been brought to the nest. The other ectoparasites noted, two mites Acarina and a feather louse Mallophagaare specific to the birds in question and would not have been acquired from their mammalian hosts. As mentioned in the preceding paragraphs, oxpeckers often feed at the sites of wounds.
This behaviour, when directed at the black rhinoceros, is commonly associated with the skin lesions infested with filariid parasites, which are found in this species but not in the white rhinoceros. The possible role of the oxpeckers in delaying the healing of such wounds or in the transmission of the parasites has yet to be clarified; there is a current research project on this topic. Hippopotamuses frequently have wounds resulting from intraspecific fighting, and these are favoured feeding sites for buphagids.
Several observers have reported that the birds, as well as taking blood, will remove fragments of tissue from the wounds. There are observations also of oxpeckers feeding on carrion, including the dressed carcases of animals. Oxpeckers held in captivity are routinely maintained on a diet in which the main component is raw minced meat.
Despite the implication that oxpeckers may actively feed on the flesh of their hosts, this may be exceptional under natural conditions.
Observations on captive rhinoceroses suggested that abrasions healed despite the attentions of the birds. As a final point of interest, a tame oxpecker fed eagerly on blood from a cut in a human finger, nibbling at the area in order to increase blood flow, but apparently not causing any further damage.
During the translocation of Red-billed Oxpeckers in South Africa, the captured birds were initially held in bomas livestock enclosureswith donkeys as hosts.
This led to problems when the birds opened wounds on the donkeys, such that the latter had to be changed on a regular rotational basis. A simple solution proved to be that of feeding the oxpeckers directly with blood, which was collected from a culled animal and treated with an anticoagulant, along with lean minced meat to which vitamin and mineral supplements had been added.
Buphagids on this diet often gained weight during the quarantine period before being released at a new locality, and it was found to be unnecessary to enclose a mammalian "host" with them.