Topic : Rare Birds
Article 30 16 May 2007
Some birds are not only geographically restricted, but are also shy, elusive and darn right difficult to locate and see – White chested Alethe Alethe fuelleborni definitely fits into this category. Added to this, these thrush-like birds are inhabitants of near-tropical lowland forest (mostly sand forest) and in southern Africa can only be found in a small region between Beira and the Zambezi River in Mozambique. Access to this region is of course a lot easier now than it was in the mid 1990’s after the civil war ravaged the region and left many rural roads, road verges and fields a nightmare with thousands of landmines.
We first ventured into these somewhat dangerous regions in the spring of 1995. Species such as White-chested Alethe, East Coast Akalat (formerly Gunning’s Robin), Blue-throated Sunbird, Chestnut-fronted Helmet-Shrike and Barred long-tailed Cuckoo were new to most of us and made for an exciting weeks camping in the lowland forests. We stumbled upon the now well known Chiniziua forest (east of Gorongoza Mountain) purely by accident but sadly only 12 yrs on, little remains of what was then a pristine patch of lowland forest.
The Alethes, with 5 recognised species are a homogenous group of thrush-like birds confined to forest undercanopy habitats of Africa. The existence of this isolated southern representative escaped the attention of earlier ornithologists during the first half of this past century, and was first discovered by Dr P A Clancey in a forest patch north of Dondo (inland of Beira) during the winter months of 1968. This first specimen was collected by him as it sat low on a branch in a clearing, the snowy white breast drawing attention to itself. Years later, I recall Dr Clancey telling me that he had at first thought it was a male Tambourine Dove Turtur tympanistria.
On our first trip to this region we failed to entice Alethes into view using tapes. Then on our second trip (also in spring) we realized that they would not respond to the tapes we were playing in spite of the fact that, to the human ear, the recorded calls sounded similar. The recordings we were using were from the northern race fuelleborni. Recordings made on site by John Jones however worked well, eliciting immediate response from these lowland birds. Their main call is a repetitive loud drawn-out, slightly quivering two-note ‘wheee-whirrrr’ often repeated in tandem by the pair when perched away from each other. Countersinging between neighbours does take place in the early morning and evening, and song during the non-breeding season is limited and somewhat quieter.
A White-chested Alethe, or an undescribed lowland form?
Clancey’s bird (Alethe fuelleborni xuthura) was described as a subspecies of White-chested Alethe, an afro-tropical montane bird that occurs almost 1 000 kilometres north in the forests of northern Malawi and through the Uluguru and Usambara mountains in Tanzania. These birds breed in the high montane forests and many of them move down to adjacent warmer lowland forests during the winter months. It was first discovered by a medical doctor, Dr F Fulleborne in south-western Tanzania towards the end of the 19 th century. During our third trip to the Chiniziua forests a few years later, my companion and birding friend Derek Coley saw a bird carrying food to a nest not far from where we were sitting. This was the first nest to have been found in southern Africa.
Our camp site was fortuitously placed right in the middle of a breeding territory so for the next few days we were able to watch these birds feeding chicks from the relative comfort of our deck chairs. We immediately climbed up to the nest which revealed two newly hatched chicks and a pipped egg. As I was later to find out, the chocolate coloured egg was different to the egg colour described by Bob Dowsett of the more northern montane species on Nyika plateau in n Malawi. The southern race xuthura has brown (not green) based chocolate (not brown to dark green) blotched eggs, occupies lowland forest year-round and does not respond well to recordings taken from the highlands of Malawi and Tanzania. Definitely a need for blood comparisons to be made between these two similar looking races. It should be remembered that it was first collected in the winter months, originally thought to be a winter visitor to the lowland sand forests to the north of Beira, and that it bred somewhere in the adjacent inland highland forests (Clancey pers comm). Until conclusive DNA tests prove otherwise, we feel that there is sufficient evidence with too many contrasting characteristics to confirm that these Mozambican birds are in fact White-chested Alethes.
The nest, a thin pad 40 mm deep, was placed 5 meters high in a deep upright fork and was made almost entirely from moss. The shallow cup (70 mm wide) was lined with rootlets and the newly hatched chicks were covered with grey down and had yellowish-orange gapes. Both birds fed the chicks and foraged thrush-like in the leaf litter, scraping and flicking leaves away in search of forest floor invertebrates. Alethes in the montane forests of Malawi and Tanzania are recorded as being very dependant on the activities of army and swarms that flush invertebrates, and, in fact, are said to be dependant on army ant activity to initiate breeding. During our 4 visits to the region, no army ant swarms were seen.
With the influx of people back into this region that was so ravaged by the bush war during the 1970’s and 1980’s, much of the riparian woodland has been plundered by logging companies, or removed by Mozambican agriculturalists. Most of the prime sand forest in the Chiniziua area is now gone, and the future of this rare, shy bird seems bleak. West of the Chiniziua sand forest region lies Gorongosa National Park, but this broken savanna woodland is too sparsely wooded, and the future of the forests on the Gorongoza massif (where this bird also occurs) is uncertain. If the forests of Mt Gorongosa are afforded some measure of protection from the Mozambican authorities, they may then hold the key to the future of this rare, shy and retiring forest bird.