Africa | Red Billed Oxpecker on Impala. Kruger National Park, South Africa | © Hendri Venter. Red-billed oxpeckers (Buphagus erythrorhynchus) are just such an example of an The relationship is obligate for the birds, and it is generally assumed that hosts that impalas are better at reducing their own tick loads than are oxpeckers. The effect that the Red-billed oxpecker has on on the Impala is called mutualism. This bird eats mainly ticks but may also eat blood-sucking flies, fleas, and lice.
A translocation is considered successful when the population is self-sustaining with breeding of released individuals and so persistence of the population. Until recently, red-billed oxpeckers were regarded as Near-threatened, however, this has recently changed and they are now listed as Least Concern.
This can partly be attributed to the various translocations of oxpeckers that have occurred since the late s. In particular the Endangered Wildlife Trust EWT has had a project which focused on reintroducing oxpeckers to where they were locally extinct in South Africa.
Consequently the current project is investigating the success of red-billed oxpeckers translocations and reintroductions. In particular we are investigating whether red-billed oxpeckers are breeding in the relocated areas and determining their persistence at translocation sites in KwaZulu-Natal KZN mainly.
The main objectives of the current project are to: This includes recording number of oxpeckers, re-trapping as many birds as possible then releasing, and ringing individuals without ring bands. We are capturing red-billed oxpeckers using mist nets that surround an animal decoy. We made a decoy using a plastic barrel on a stand with a tanned zebra skin draped over it.
A tanned zebra skin was chosen as we have had several sightings with of red-billed oxpeckers feeding off of zebra. In some areas, we need a game ranger to escort us while we set up in the dark. We have heard elephants in the nearby bush feeding and lions roaring less than a kilometer away. We have also seen how other animals react to the decoy that has legs flapping in the wind. For example, two zebra and a lone blue wildebeest stared and snorted at the decoy.
Mist netting oxpeckers involves lots of waiting and patience. Sometimes red-billed oxpeckers tease us by sitting on top of our poles and nets and so avoid getting caught.
Each ring has a specific series of numbers and serves as an identification tag for the bird when the bird is caught again: Measuring the tail length of a red-billed oxpecker. Captured birds are checked for a brood patch to determine their breeding status. All this information helps determine when these birds moult, breed and how long they live for. The latter assists in determining extent of range expansion as the genetics of the founder populations are known.
A feather sample is taken for isotope analysis. Ecto-parasites are collected to determine parasite load of the birds caught. We release the birds at their capture sites as soon as possible. We conduct regular transect surveys to determine population estimates of oxpeckers at selected release sites.
Feeding preferences of Oxpeckers in Kruger National Park, South Africa
The work was carried out in the lowveld of southern Zimbabwe on red-billed oxpeckers and a small herd of domestic cattle. Sentinel Ranch has a large population of red-billed oxpeckers that feed both on game and a study herd of 22 Bonsmara oxen the Bonsmara is a South African variety of cow, a cross between Bos taurus and Bos indicus. Up to 60 individual birds visited the kraal cattle enclosure every morning, where they would spend approximately 2 h feeding on the animals.
Small groups of oxpeckers continued to visit and feed on the oxen in the field throughout the day Weeks, Cattle are hosts to five species of ixodid tick at Sentinel blue ticks, brown ear ticks, bont ticks Amblyommma hebraeum, red-legged ticks Rhipicephalus evertsi, and bont-legged ticks Hyalomma marginatum.
Ticks have three life stages larva, nymph, and adulteach of which requires a different individual host on which they attach and engorge with blood before dropping off and metamorphosing to the next stage. The exception is the one-host blue tick, which goes through its entire life cycle a process that takes roughly 4 weeks on a single host. Adult male ticks of all species spend up to a month attached to their host; adult females are attached for about 1 week. For the experiment, I arbitrarily divided the herd into 2 groups of 11 animals, experimentals and controls.
For the first treatment 21 November DecemberI excluded oxpeckers from the experimental group for 4 weeks. Because adult ticks are continuously attaching to the hosts and their drop-off rate is low, this period would have been sufficient to detect any effect oxpeckers might have had on tick loads.
An assistant stayed with the herd throughout the day oxpeckers do not feed during the night and chased off any oxpeckers that attempted to land on the oxen.
I remained with the control group, which oxpeckers continued to visit and feed on as normal.
The two groups fed in two separate grazing areas, which I alternated every 2 days. They spent the night in separate cattle kraals, which I alternated every week.
Controlling for grazing areas was particularly important because the ranch has large populations of other potential tick hosts, notably impala Aepyceros melampuseland Taurotragus oryxkudu Tragelaphus strepsicerosand warthog Phacochoerus aethipicus. The density of ticks may therefore have varied from area to area.
Red-billed oxpeckers: vampires or tickbirds? | Behavioral Ecology | Oxford Academic
It is also important to note that the developmental period needed for engorged nymphal ticks to change into adult ticks is close to 2 months for brown ear ticks see, e.
This does not take into account the additional time required for the adult's cuticle to harden, the tick to start searching for a new host, and the delay while it finds a host. There was thus no danger of the results being confounded by cross-contamination between control and experimental herds.
For the second treatment 17 January FebruaryI switched the groups so that the experimentals became controls and vice versa. For the third treatment 19 August SeptemberI arbitrarily selected a different combination of oxen to fill the control and experimental groups.
Although there were originally 22 oxen, 3 animals died during the year, so the sample size varies slightly between experiments. For each animal, I counted all the adult ticks, identifying them to species level, and, for the bont ticks Ambylomma hebraeumto sex. I also assigned an earwax score based on a visual assessment of the inner portion of the right ear using the following scale: I repeated full tick counts, wound scores, and earwax measures on all animals every week. I only scored adult ticks, as there is no valid technique for counting larval ticks on a live animal Mooring and McKenzie,and it is difficult and time consuming to look for nymphal ticks.
Adults are also accurate gauges of the overall tick load of an animal Mooring and McKenzie, With all the tick analyses, therefore, I analyzed not only the overall changes in totals, but also the changes in species' totals. I compared the median monthly change in tick loads between experimental and control oxen for each treatment and corrected for this multiple comparison with a sequential Bonferroni correction Sokal and Rohlf, Because the data are not normally distributed, all my tests are nonparametric Siegel and Castellan, All statistical tests are two-tailed with the significance level set at 0.
Absence of oxpeckers also had little effect on infestation changes at the level of species and sex.
Blue ticks did not appear in any of the three replicates, and brown ear ticks, a seasonal species, only appeared in the second. Of these 16 remaining results, only 1 showed a significantly greater increase on experimental oxen Figure 2.