Peter J Ginn ARPS APSSA
| Stretching across southern
central Africa is a broad swath of broad-leaved semi-deciduous woodland called the MIOMBO
woodlands. The trees lose all their leaves at the end of winter and are bare for about 2-4
weeks before growing the new leaves for spring. One of the strange features of the
Brachystegia trees within these woodlands is that the new leaves emerge without any
chlorophyll so appear in various shades of red & brown reminiscent of the fall colours
of the northern hemisphere. It is at this time that the Red-headed Weavers build their
"stick" nests using the centre stems of the Brachystegia leaves. |
Red-headed Weaver |
These woodlands are dominated by different species or groups of trees in each area. The Zimbabwean plateau woodlands are dominated by three Brachystegia
species (B. spiciformis; B. glaucascens; B. boehmii) so these woodlands are called Brachystegia woodlands. Further west we find the Baikiaia woodlands.
The trees vary in height according to the soil and rainfall. The best areas have a canopy at about 30-50 ft above the ground, while many
areas have the canopy at 20-30 feet. In the east, higher elevations result in a lower
canopy.
| These woodlands have many of the typical woodland bird species found throughout much of eastern & southern Africa,
but they also are home to a number of bird species which are not normally found outside these woodlands. Birds such as the Mashona Hyliota Hyliota austalis and the Spotted
Creeper Salpornis spilonata spring to mind. |
Mashona Hyliota |
Black-collared Barbet |
Over much of the plateau the
woodlands are being degraded through the collecting of dead wood. This wood is very
important as fuel for the farm workers, but the loss of dead wood means a loss of the many
insect species which live in the dead wood. This in turn means that certain species such
as the woodpeckers decrease in numbers. A further problem is that where there are no dead
stumps, the barbets and woodpeckers lack potential nest sites. These two families are
important in that they create nest holes which can be used by other hole nesting species
such as the wood hoopoes, tits and starlings. |
Fortunately a number of enlightened farmers are providing fuel wood from plantations (woodlots) of Eucalypt trees which grow very much more rapidly
than the indigenous trees. There are also woodland reserves where one can find the full range of Brachystegia woodland bird species.
One of the most interesting aspects of looking for birds in these woodlands is that, outside the nesting season, most of the insectivorous species
join together to form what are called "Bird Parties". These groups of birds move in a loose group through the woodlands in search of food. The birds may be spread over
several acres, but they are always in contact with certain species apparently keeping the group together through their contact calls. The Miombo (Northern) Grey Tit Parus
griseiventris seems to be one of the major "contact" species as they have a soft call by which the individuals keep in contact and to which the other species respond
when the tits change direction!
Each species forages in a different way. For example the Yellow-throated Sparrow Petronia superciliaris forages up the trunks and along the
larger branches while the Grey-headed Sparrow Passer griseus feeds on the ground. The Black-cheeked Canary Serinus mennelli will be seen in the leaves towards the
ends of branches, while the similar Streaky-headed Canary S. gularis feeds in weeds near the ground.
Female Purple-Backed Sunbird
 |
The Purple-backed Sunbird Anthreptes reichnowii is a small bird which is often found in the bird
parties. It forages in the canopy and is therefore often overlooked. Unlike most of
our sunbirds which have a long curved bill, this species is a member of the Anthreptes
group and has a relatively short curved bill. It was presumed that thsi was because
the birds ate more insects than nectar, but this does not appear to be the case as the
birds are attracted to flowing plants especially aloes and other plants with tubular
flowers. They nest as the trees are dropping their leaves and so attaches dead leaves to
the outside of the nest as shown in the photograph. The nest looks like an old spider's
nest even when new! |
The Fork-tailed Drongo Dicrurus adsimilis is particularly interesting because it sits on a conspicuous perch from which it hawks
insects disturbed by the other foraging birds. They are always on the alert for movement and are usually the first to see the approach of danger – often in the form of one of
the many small grey raptors which are part of the avifauna of the woodlands. If one gives an alarm call all the birds disappear into nearest thick foliage – they do not fly
away as this would put them at risk from an approaching raptor.
Around Marondera where I do most of my Brachystegia birding, every single insectivorous species has been recorded in a bird party at one time
or another. In addition I have recorded many seed-eating species. To date I have recorded over 70 species in bird parties, but so far have never recorded more than 30 species in a
single party. Most of the Brachystegia "specials" are usually to be found in these bird parties while the surrounding woodlands appear to be devoid of birds.
This can be really frustrating if one cannot find a bird party! Perhaps the one exception is the Chinspot Batis Batis molitor. This species occurs in pairs which maintain territory throughout the year.
| There are a number of small
to medium grey raptors which occur in the woodlands. They form a series increasing in size
from the small Little Sparrowhawk Accipiter minullus to the fairly large Dark
Chanting Goshawk Melierax metabates. There are two interesting features in this
series (a) the female of the smaller species is roughly the same size as the male of the
next largest species (females being larger than males), (b) the smallest species (Little
Sparrowhawk) has white on the rump, the next largest (Little Banded Goshawk) has not
white, and so on alternately as size increases! |
Little Sparrowhawk
 |
African Goshawk
 |
Some species like the Little
Sparrowhawk & Gabar Goshawk Micronisus gabar are essentially bird eaters,
catching small birds in high speed chases through the trees. Others like the Little Banded
Goshawk Accipiter badius and Lizard Buzzard Kaupifalco monogrammicus feed
mainly if not entirely on lizards and geckos. Apart from the Lizard Buzzard which is often
seen sitting on a conspicuous perch, the others are easily overlooked as they sit quietly
under the canopy for most of the day. They will even allow one to walk under them if they
think they have not been spotted! Very early in the morning – just before sunrise
– the African Goshawk Accipiter tachiro can be heard making its clicking call
as it flies high over the woodland. |
The Brachystegia woodlands like all the Miombo woodlands
of central Africa are an interesting and worthwhile habitat for birders to visit. They are
one of the most benign habitats with comparatively few thorns, grass seeds and irritant
plants or insects. The Marondera area of Zimbabwe area boasts some 422 bird species recorded in
the various habitats in the district.
