Anyone who has visited the north-western and north-eastern parts of the country will have noticed the brown-grey birds with the red or yellow-red beaks as they busy themselves on cattle or wild mammals. When you want to take a photo they usually hide on the side of the animal which is turned away from you. These birds are Red-billed and Yellow-billed Oxpeckers. They mainly feed on ticks, not on maggots.
Which areas the birds prefer, where they spend the night, whether they repeatedly look for ticks on the same animals, whether they regularly visit cattle and wild animals for foraging, whether they live in family groups only and how they are affected by pesticides and other chemicals – all this and more is what Sinvula Michael Lukubwe wants to find out. He is a lecturer for wildlife management and ecotourism at the Katima Mulilo campus of the University of Namibia (UNAM).
Together with experienced bird ringer Mark Boorman from Swakopmund I had the opportunity to assist Michael Lukubwe in the second half of May this year. We caught Oxpeckers, ringed and measured them. Before releasing the birds we also collected faecal samples while Lukubwe’s colleague, veterinarian Dr Simba Chinyoka, took blood samples of each bird for various tests. In the five days that we spent at the Izumba settlement on the Chobe River, not far from the Gondwana Collection’s Chobe River Camp, we managed to catch 37 Oxpeckers: 10 yellow-billed and 27 red-billed ones.
During the preparatory phase of his research project, Lukubwe, with the help of locals and staff of the Chobe River Camp, identified five Oxpecker roosts in cavities in trees at various locations. The plan was to close the cavities with custom-made nets when the birds settled into the sleeping place before dark and catch them the next morning when they were ready to leave.
First observations after our arrival had some unexpected results. One of the roosts was no longer used by Oxpeckers – tree rats had moved in there. Another one in the vicinity was used by Black-collared Barbets and at yet another Oxpecker roost, near a settlement about three kilometres from Chobe River Camp, we watched three squirrels in the tree hole but no Oxpeckers were to be seen.
So we decided to try our luck at the cattle kraal of the Izumba settlement. The inhabitants told us that numerous Oxpeckers of both species would arrive there, especially in the morning. We set up our nets on the southern side of the kraal and on the first morning just before 7 o’clock caught the first seven oxpeckers – five red-billed and two yellow-billed ones. The following morning we found only three Red-billed Oxpeckers in the net. Therefore we decided to section off part of the 25×25 metre kraal after opening the nets in order to get the cattle to move as close to the nets as possible. We attached a number of tin cans to the two ropes with which we divided the kraal every morning before the Oxpeckers arrived. This forced the cattle to move into the southern section and it was easier to shoo the birds into the nets set up outside the kraal.
Thus the first step for studying Oxpeckers in the eastern Zambezi Region has been made. GPS tracking systems are now urgently needed to find out where the birds spend the day and where they rest at night, how large the area is that they use, where they breed and how the two species get along. Tracking devices with a relatively short antenna and a weight of no more than two or three grams are required for this purpose. Researcher Michael Lukubwe hopes to raise the finances necessary to obtain the devices to be able to study Oxpeckers more intensively.
Some of the communal farmers have recognized the value of these specialized birds, others tolerate them, but there are still some who do not want them near their cattle. The Yellow-billed Oxpecker is classified as critically endangered in Namibia, while the Red-billed Oxpecker is not considered at risk.
Author: Dirk Heinrich