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Birds of the Mafia Archipelago

by  Dudley B. Iles B.Sc.

 

INTRODUCTION

 

During the last twenty years, there has been a steady increase in numbers of Europeans and Americans spending their vacations in Africa. Amongst the usual reasons for taking holidays, many tourists have an underlying curiosity to experience the colourful history, culture and exceptional natural history of the continent. The countries of Kenya and Tanzania not only provide game parks but an exceptionally varied coast and off shore islands with a long human history and a less well known natural history.

Whilst the northern Tanzanian islands of Zanzibar are better documented as regards their natural history, the Mafia islands, about 90 miles to the south, are much less known.

Tourists have only recently discovered Mafia, encouraged by the establishment of  the attractive and modern Kinasi Lodge. Inevitably, diving, snorkelling and other water sports have been the main attractions for visitors. The impact of the growing human population on the local fishing community and the wild life has been under consideration with the establishment of a marine park based on the extensive and beautiful Chole bay. Studies of the bay are clearly indicating that it and its surrounding island shores are important for the considerable numbers of off-breeding shore birds which visit this region. As well as resident breeding species, all are directly or indirectly dependant for food on the rich marine animal life, as are the local human communities which surround the islands’ coast.

During the occupation of Mafia by Germany, the island was visited briefly by ornithologists with the emphasis on specimen collecting, notably Von der Decken (1870),  and Voeltzkow who visited the island for a few weeks in 1908 and 1923, and by Baumann (1896) a geologist who made passing reference to the natural history.

Sporadic collecting was undertaken during the early British occupation. King( 1917) and N.R. Fuggles-Couchman (1936) spent two days on Mafia collecting and making  observations.   With contributions from G. S. Brown of the Agricultural Department on Mafia, and District  Administrators, notably  Darling and Piggott. R. E Moreau was able to bring together the known Ornithological records of Mafia in the 1940s. More recently there have been contributions from Ornithologists known to those of us familiar with the current text books on  East African birds.

In association with  Frontier expeditions, C.O.F. Mlingwa and C.A. Msuya from the Department of Zoology at Dar-es-Salaam University,  made a 10 day study on Mafia , one in May and another in November 1992. There has been a number of expeditions by Frontier largely to study the marine environment but also to make contributions to the avifauna. Tourists have also left their records with Kinasi Lodge or with the World Wildlife Fund office at Utende. Thus our knowledge of the Mafia avifauna has been limited, but has slowly built up from short visits by Europeans and through the knowledge of local people.

There is still more to learn about the distribution, movements and behaviour of Mafia birds and perhaps other species to be recorded. The visitor to Mafia can make a greater contribution to our knowledge of the natural history than they would in similar circumstances in Europe.

To begin to understand the birds of Mafia a brief look at its geography and its vegetation is of interest.

The Mafia group of islands lies 80 south of the Equator in the Indian Ocean, roughly 15 kilometres, east of the Rufiji river delta on the mainland of Tanzania. Between is a shallow channel with small islands and reefs, an important trading route along the African coast.

The main island of Mafia is some 40 kilometres from north to south and 16 kilometres from east to west at its widest; a little over half the size of Unguja (Known to most tourists as ‘Zanzibar’). To the south east are the smaller islands of Chole, Juani, and Jibondo associated with many coral islets and sand bars. They separate the shallow Chole bay from the sea and  are often connected at low spring tides. The Mafia islands are composed mainly of coral rag and sandy sediment never more than 60 metres in height.

The human population is smaller than Zanzibar, many living in or round Kilindoni, the present day district capital. Most live in small villages or on scattered farms (shambas) in the traditional manner. Over the years much of the natural vegetation has been cleared for cultivation, some being allowed to return to secondary bush from time to time. Coconut plantations dominate the landscape but there is also extensive cultivation of cashew trees, bananas, cassava and maize. On Chole Island, oranges, limes and many other exotic fruit are also grown.

The natural vegetation and its corresponding animal life, like many regions of the tropics, is under pressure from cultivation. Shifting agriculture has changed much of the landscape. Mangroves are cut for building timbers and firewood and the remaining natural forests are isolated and growing smaller all the time. As the visitor walks along the forest paths, he or she often breaks out into small fields of maize recently cut out of the woodland. The few remaining forest patches ought to be declared reserves and encroachment stopped before they become too small to support some of the forest wildlife.

If tourism can be made to benefit the local people through the issue of permits and the training of guides, perhaps the future of these forest patches can be assured.

Botanical studies by Greenaway (1938) Pratt, Greenaway and Gwynne (1966) and Rogers (1988) recognised eight major habitats on Mafia.

Distribution of the resident bird populations can be associated with these habitat-vegetation types:

1   Ocean

2   Inter-tidal mud flats and beaches

3   Coastal thickets

4   Cultivated and built-up areas

5   Swamps and ponds

6   Grassland

7   Mangroves

8   Coastal forest

It seems reasonable to begin a survey of Mafia’s birds around Chole Bay, where most visitors begin their holiday. They are driven from the informal airport in Kilindoni along one of the two main dust roads of Mafia, to the lodges overlooking one of the most unspoilt and biologically interesting bays in Tanzania.

Chole Bay, protected from the ocean to the east by a group of small islands and islets, is extremely shallow for the most part and bordered by mangrove swamps and sandy beaches. At low tide vast areas of the southern end of the bay are exposed to reveal soft silts and sand with coral rock platforms and pools rich in marine invertebrates.

‘Shore birds’, as the Americans call them, or waders (the term used in Europe and Africa) are small- to medium-sized long-legged birds. Many spend their breeding season by rivers and on marshes in the far north of Eurasia whilst other species prefer the lake edges of more central and southern regions. They are long-distance fliers, and after breeding, many travel thousands of kilometres across sea and land, to more favourable regions of the world. Many waders pass through Eastern Europe, to arrive on the east coast of Africa. Some continue to the Cape in South Africa where, after a few months, they return once more.

Chole Bay provides a temporary resting and feeding station for many waders continuing further south, whilst others may spend all their winter here. Between September and April birds can be seen busily feeding amongst the pools at low tide where they select worms, shellfish, crustaceans and even small fish.  Each species is adapted in bill length, length of leg and in size to allow maximum efficiency for collecting food but with little competition between species.

As the tide advances, mixed parties become more concentrated along the upper shore. As each approaching high tide covers their food, flocks can be seen flying , over the incoming water, towards the mangrove swamps and rocky islets to the north and east of the bay where they safely rest and preen until the water begins to recede once more.

Whimbrel, with their long curved bills, Grey Plover, lacking their summer black bellies, are perhaps the commonest waders; Ringed Plover, Curlew Sandpipers, Little Stint and Greenshank make up the numbers from the far north. There are other waders less familiar to the ornithologist from Western Europe; Greater Sand Plovers which breed from Jordan to central Asia, and Terek Sandpipers, their up curved bills appearing out of proportion to their dumpy bodies.

One of the most interesting waders is the striking black and white Crab Plovers. These heavy billed birds breed on sandy shores along the Persian Gulf and Somalia spending their off-season on the sand and mud shores of East Africa as far south as Mozambique. The successful breeding pairs are accompanied by their single smoky grey and white offspring. Chole Bay is an important feeding area for these birds. One of the most beautiful sights of Mafia is the high tide flights of Crab Plovers making their way low across the water to the sanctuary of the mangroves there to await the turning of the tide. Although most of these waders return north, a few, perhaps injured or immature birds remain through the year.

Many of the herons seen on the Mafia shores are resident. Small solitary Green-backed Herons with orange yellow legs are often disturbed from the rock pools. But by far the commonest is the larger all-white or mouse grey heron with dark legs and yellow/orange feet. There are intermediates between these extremes indicating that they are of the same species, hence the now recognised name of Dimorphic Heron, related closely to the Western Reef heron. A third smaller white heron is rarely found on Chole Bay shores but spends its time foraging for large insects and frogs disturbed by the feet of cattle as they graze on Mafia’s grasslands. These Cattle Egrets take to the air at dusk and fly across the water to offshore islands to roost. One large roost is located in the mangroves off the northern tip of Chole Island. Here in the non- breeding season up to 300 Cattle Egrets and 250 Dimorphic Herons arrive at the same time as 1000 or more fruit bats leave their day roosts on Chole, to feed on the fruit trees of Mafia. Occasionally Black Heron, Night Herons or even a Madagascar Squacco Heron joins the roost. Towards the end of the year and the beginning of the next, Bee-eaters also use the mangroves as a roost with as many as 600 birds present in January.

North of Chole, at the entrance to the bay and between Juani and Jibondo islands are several coral rock islets, each shaped little gigantic mushrooms by wave action, whilst the tops  have been harshly sculptured by wind and rain into razor sharp ridges and gullies . Some of these islets play host to breeding colonies of Dimorphic Herons and Cattle Egrets, shared with a few Long-tailed Cormorants, Green-backed Herons and Red-eyed Doves, their nests scattered amongst the cactus-like Euphorbias safe from rat and man. The Cattle Egrets need to travel across plantations and sea to supply their young with regurgitated food. The islets are also favourite vantage points for the resident Fish Eagle and the occasional wintering Osprey.

The islands of Chole, Juani and Jibondo reflect Mafia’s avifauna but with one or two curiosities. Jibondo might still support a small colony of Goliath herons in low trees along the edge of a coral cliff. Juani and Chole have breeding populations of Laughing Doves. It is thought they may have been introduced there some time in the past (Mackworth-Praed and Grant 1960). Occasionally parties of Greater Flamingos present themselves on offshore sand bars at Jibondo, during their movements to a salt lake west of Lindi.

Across the Bay, on the main island of Mafia, the shore is once more extensively protected by mangroves. The sandy cliffs of the old beach support a small breeding colony of Pied Kingfishers before passing inland near Kinasi Lodge. Between the cliff and the mangroves are coastal bush, cultivated fields and marshy grassland.  Scattered throughout are coconut palms and cashew trees. A walk between the mangroves and the bush reveals many of the typical resident birds of Mafia. Noisy family parties of Scimitarbills move between the two. Families of Collared Sunbirds forage in the mangrove leaves searching for spiders and insects; Black-backed Puffbacks are common, the males seen in stiff winged display flight above the mangroves exhibiting their puffed-up white rump feathers. Hidden in deep bush, wall eyed Sombre Greenbuls sing their warbling song. Along the shore Hadada Ibis stand like sentinels on the top of leafless palm trees where occasionally Broad-billed Rollers can be seen.   Watch for pairs of Water Dikkop, much like European Stone Curlew, or a silently-rising Gabon Nightjar, along the quieter sandy beaches.

Mangroves and open bush are favourite winter habitats for Spotted Flycatchers, darting out from a favourite branch to capture a passing insect before returning to the same perch. Orioles, bright yellow males and discretely green immatures and females favour the mangroves. The males often briefly uttering their rich warble in the early morning.  Madagascar Bee-eaters are resident breeding birds but are joined by similar Blue-cheeked Bee-eaters in their off-season.

Inland, palm plantations with scattered houses line the roads and paths. High in the palms, often above a house, colonies of Black-headed Weavers hang their nests from the underside of the large feathery leaves. The colony is regularly visited throughout the year and always with high activity, a steady stream of birds carrying strings of grass to weave into their nest, whilst displaying males hang with fluttering wings. Many of these colonies have been in use for several bird generations.

Palm Swifts are the most widespread swift of Mafia. The simple nest is built of feathers held together with saliva suspended precariously and vertically along a palm frond. The two eggs are incubated with the bird in a vertical position.

Telegraph poles and wires are frequently used by birds in various ways, as vantage perches from which to hawk after passing insects or to watch for those crawling below, for advertising territory or simply to rest and preen. The telephone wires from Kilindoni to Utende are no exception and give the recently arrived visitor their first sightings of some of Mafia’s commoner birds. Striped Kingfishers and Lilac-breasted Rollers hunt for ground insects below, the latter also perform their spectacular display flights before returning to their chosen pole. Male Fan-tailed Widowbirds set up their territories from the nearby wire, Bee-eaters hawk for flies in small groups, and Striped Swallows just rest between energetic feeding flights.

Kilindoni is the only town on Mafia. It is spacious with a variety of habitats well worth checking on a visit or whilst waiting for your flight to Dar-es Salaam. Overhead Black Kites and Pied Crows are constantly scavenging or soaring over the remnant forest close to the airport. Little swifts are resident but during changeable off season weather conditions,    Eurasian Common Swifts may suddenly appear flying ahead of the storm.

Mafia airport, unlike more formal ones, permits the visitor to walk around the airstrip.  Richard’s Pipits, Yellow Wagtails, Northern Wheatears and Zitting Cisticola are to be looked for.  Near by, and close to the town, is a shallow lagoon, mostly dry in the middle months of the year, but reed fringed in the wet season. Here  Jacana  breed and  often visited by parties of White-faced Whistling Duck and the diminutive pigmy goose before being disturbed by local children.

Much of the roadside, from Kilidoni to Utende, is grassland with scattered bushes, resembling the Savannah of the mainland coast. During monsoon periods they may become flooded for many weeks.  Zitting Cisticolas are often the only bird present in the dry season. These small warblers with their monotonous flight song are the most widespread of the Cisticolas being found in southern Asia, Australia and southern Europe. Cattle feeding in Mafia’s grasslands attract white Cattle Egrets, often showing fawn crowns and backs, an indication of breeding condition. In wetter times Fan-tailed Widowbirds display over the tall grass and neat black and white male Pin-tail Whydahs perform their jerky aerial displays with trailing tails. The trilling call of Water Dikkop is a common night sound particularly where open water is to be found.

Scattered throughout Mafia are permanent pools often surrounded by reeds and covered with the floating leaves of purple water lilies. Some were artificially produced when the dirt road to the north was built. The larger ones contain dead trees, drowned by the water, on which Egrets, Malachite Kingfishers, Lilac-breasted Rollers and even Darters perch from time to time. Some are surrounded by tree heath (Philippia mafiensis) whilst others open on to grassland. Visits to these pools are most productive just before dusk when shyer water birds are likely to feed outside the reed cover. Typical resident species are Jacana, Black Crake, Allen’s Gallinule and White-faced Whistling Duck, by far the commonest duck on Mafia.  During the non-breeding season for northern migrants, Purple Herons, Grey Herons, and Wood Sandpipers frequent suitable margins. Many of these pools are rarely visited by ornithologists because of their inaccessibility and may yet have surprises.

On the east coast, north from the northern arm of Chole Bay to Ras Mkumbi the coast line is largely composed of wave- and wind- eroded cliffs and platforms. The cliff top is a narrow strip of short grassland with scattered bushes often pruned by wind and spray, in places almost impenetrable coastal bush. Apart from the resident species, this coastline is ideal for observing migration.  Its position in relation to the mainland puts it close to the natural coastal migration route of East Africa. The variety of vegetation provides shelter and feeding for migrants.

Scattered parties of waders rest and feed by the side of the rock pools below the cliffs or at the margins of pools along the cliff edge; Pipits (including two Red-throated Pipits on one occasion) feed with Yellow Wagtails in the short grass. Red-backed shrike and Spotted Flycatchers hunt for insects from the bushes. Occasional breeding Senegal Plovers, passing Ospreys,  and terns frequent the cliff edge. Though hard to reach, this is an area capable of providing exciting bird watching through much of the year.

Patches of original coastal evergreen forest still remain though much reduced since the days of Bauman’s visit (Voeltzkow 1923). Although the human population is smaller than Zanzibar’s, there has been a steady encroachment of Mafia’s remaining forest areas where there is suitable ground for cultivation. Many of the remaining trees are of medium size growing on coral rag,  and the undergrowth is often dense thickets of woody climbers and shrubs. The visitor may explore by using the villager’s well-worn paths often leading to clearings. There are occasional small swampy stream which winds its way through the forest to the shore. Small patches of forest remain in Kilindoni, Chunguruma, Mlola, stretching north along the east coast and near to Kanga-Ngome in the remoter north of the island. These are all that is left of what must have been extensive coastal forests perhaps separated by natural grassland and heath land. Although likely to be restricted in their avifauna because of their island status and reduced size, these forest patches have recently produced interesting bird records.

At bush level, Little Greenbul have been recorded in all forest patches, Eastern Bearded Scrub Robin in Mlola, and Red-capped Robinchats appear widespread if difficult to see.  Camaropteras and Olive Sunbirds are common. Green Pigeons and occasionally Tambourine Dove can be seen in most forest areas as indeed in coastal bush. Mixed ‘waves’ of small birds in the canopy may include Golden-rumped Tinkerbirds, Black-throated Wattle-eyes and Collared Sunbirds. Black Cuckoo Shrikes have been recorded within Kilnidoni forest.  Msuya and Mlingwa recorded Livingstone’s Turaco in1990 and 1992, Crowned Hornbill during   the November Frontier expedition of 1992, and Narina’s Trogons, all within the bounds of the Mlola forest. Pygmy Kingfishers are known and are more likely to be caught in mist nets stretched across a forest  path than seen. Although resident in East African coastal forests their numbers may be enhanced by migrants from the south.

As the forest merges into plantations or grassland or bush,other species forage along the forest edge, notably parties of non-breeding weavers, mannikins, coucals and doves. Streams pass through cultivated fields and forest before weaving their way through mangroves or sandy estuaries to the sea. Within the Mrora forest the smaller herons forage along the stream banks. Malachite and occasionally, Mangrove Kingfishers can be seen especially nearer the shore. In the northern winter, the ubiquitous Common Sandpiper is nearly always present. Perhaps unexpectedly, bat-like Bohm’s Spinetail hawk over these quiet streams.

The continual enjoyment of Mafia’s diverse natural history by tourists and local people alike will depend, in the future, on the protection and management of the more delicate habitats, particularly the remaining forest and coastal regions. The work of the African world Wildlife Fund, local entrepreneurs and residents are vital to preserving the beauty and prosperity of Mafia.

Acknowledgements

I am indebted to Peter Byrne for his help, enthusiasm and support, the inhabitants of Chole Island whose hospitality and cheerful hard work made my stay on Chole memorable, and to the staff of Kinsasi lodge whose advice and experience I valued. To John Bateman and Kathryn Belk for their editing and to Neil Baker for his comments on Mafia’s avifauna.

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