Colours of Wildlife: Whitebrowed Sparrow-Weaver
Created | Updated Apr 17, 2016
Whitebrowed Sparrow-Weaver
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
Time again for a species very familiar to me, but probably not to most readers! This is a Whitebrowed Sparrow-Weaver, Plocepasser mahali. In Afrikaans it is known as a 'Koringvoël', that is 'Wheat-bird'. This is to me the original angry bird. With its heavy white eyebrows, rather sullen look and scolding ‘chuck-chuck’ call whenever humans venture close to it, a sparrow-weaver always seems somewhat miffed. But actually it is one of the tamest local bird species; though always very alert and cautious when humans are around, they become quite tame and can be approached fairly closely. Though not as fully adapted to humans as sparrows are, they are at present quite common in and around the town of Polokwane. They only need thorn trees to nest in. Their favourite tree is the umbrella thorn. These trees would almost look incomplete without the untidy balls of grass stalks that are the sparrow-weavers' nests. These days, more local gardeners are willing to plant thorny trees in their gardens, and so these chunky weavers are coming to town and living amongst us.
Sparrow or Weaver?
The sparrow-weaver straddles a line. Most readers will be familiar with sparrows: the house sparrow, originally from Europe and Asia, today is found all over the world, having accompanied humans and now being common in towns and cities, where it scavenges crumbs and bits of our leftovers and nests on or in our houses and other buildings. Africa has several indigenous sparrow species as well, all of which are mainly coloured in blacks, whites, browns and greys. Sparrows tend to pair up, and make untidy grass nests, in which the male helps the female to raise their chicks. Weavers, now, are in Africa an extremely diverse group, and most of them are brightly coloured in yellows, oranges, reds, blacks and whites. The weavers, as their name suggests, make intricately woven nests of grass and other fibrous materials. Most weavers are polygynous: a single male, who can demonstrate exceptional skill in nest building and singing, will attract and mate with several females, who then go and raise their chicks alone. Weavers often nest in large colonies, preferring thorny trees over water.
The sparrow-weavers look like large sparrows, and also are monogamous, a single male and female raising their chicks together. They also make nests that are on the untidy side – but these nests are more substantial than those of most sparrows. The nests consist of bunches of tough grass stalks shaped into what on the outside looks like a ball, the stalks just shoved in together. On the inside, the nest is well-structured, with a single chamber to which two entrances lead. Most nests are for roosting. Sparrow-weavers occur in small flocks, a single male and female being the dominant couple, the others being helpers. Each group has a single tree in which they all nest separately – indeed there are often more nests in the tree than birds. The nests are typically bundled towards one side of the tree, away from the prevailing winds. The two separate entrances are useful because if a snake or other predator enters at one entrance, the bird inside can escape by the other entrance. The several empty nests per tree can also confuse predators and give the weavers time to escape. All members of the flock build the nests; indeed, nest-building seems to be going on constantly.
In suitable habitat, sparrow-weaver flocks can occur close to each other. The dominant adults of two separate flocks will utter their scolding 'chuck-chuck' calls to challenge each other, and also will pose with grass stalks in their bills, these simply being visual props. They have more intricate territorial calls, these being a short chirpy song, proclaimed from a thorny twig at the edge of the tree canopy. This way they assert their territories. In fact, even the nests themselves, that so liberally festoon the thorn trees, are advertisements of the sparrow-weavers occupying them. They make it very easy for birdwatchers to find the weavers, too!
Sparrow-weavers occur in habitat with two different components. The first is ample grass cover, because they need a constant supply of building materials. The second component is areas denuded of grass! This is where they actually hunt for their food, which is mainly harvester termites. These large termites are unusual for being active by day, and for having dark markings on their bodies which protect them from the sun. Harvester termites are extremely common in the African savannah, their grass-gathering activity being audible as a constant, soft rustling almost everywhere. Sparrow-weavers need places where the grass is very short and the soil surface is visible, so as to be able to spot the termites so that they can catch them. So they need a varied landscape with long and short grass both, for their full needs. Like their relatives the sociable weavers, they're found in fairly dry regions, because their grassy nests can become mouldy or even rot in a moist climate.
Apart from harvester termites, sparrow-weavers also eat other insects, as well as seeds, mainly of grasses. They feed on the ground, hopping about and pecking up anything edible they find.
For sparrow-weavers, the breeding season starts with the rains – in the African savannah, this is the spring to early summer. In each group, only the dominant male and female breeds. The courtship consists of the male performing a short dance prior to mating with the female. He shuffles with his feet along a branch, first moving away and then moving towards her and repeating this for about seven minutes.
The female will fix one of the nests up for breeding by closing one of the entrance holes. That minimizes the chances that eggs may fall out of the nest. Each clutch consists of one to four eggs, most typically two. The female incubates alone, but the male and helpers will bring her, and later the chicks, food. The chicks fledge about three weeks after hatching.
Sparrow-weavers are quite common, widespread and adaptable. They occur from South Africa northward to south-central and eastern Africa, up to Ethiopia. Three additional, similar species are found in tropical Africa, also in dry and open savannah regions.
