The biology, ecology and conservation of four Flufftail species, Sarothrura (Aves: Rallidae)

Abstract

The distribution, status, biology and ecology of four flufftail species were investigated in South Africa and Zimbabwe. The Redchested Flufftail is a successful and widely distributed species, occupying a wide range of dense vegetation, from seasonally wet grassland and sedges to permanently shallowly flooded reedbeds. It colonizes artificially created wetland patches and occupies very small patches of suitable habitat. Redchested Flufftails maintain a permanent pair bond and are permanently territorial and entirely sedentary. Their habitat is relatively stable but unpredictable catastrophic events such as burning may force temporary emigration in winter or spring. Displaced birds move a short distance, occupy often marginally suitable habitat and recolonize burned areas as soon as vegetation cover becomes adequate. Periodic burning improves habitat quality, and recommendations are formulated for the management of wetland habitats by burning. The size of the winter territory is larger than the minimum required for survival and provides an insurance against forced emigration, while immatures often share parental territories in winter. The Striped Flufftail's grassland habitats in Natal are decreasing and its numbers are declining. Striped Flufftails are sedentary in low-altitude grassland habitats, but in high-altitude sourveld the decrease in invertebrate food forces emigration in April-June, when the birds move to unknown wintering destinations (movements are possibly altitudinal). Return time to unburned vegetation is dependent upon invertebrate food availability. Return time to burned vegetation is governed by the development of suitable cover, which may occur too late in the breeding season to permit occupation. The species is well adapted to frequent burning of its habitats, which serves to maintain suitable fire-climax grassland, but is also adapted to post-fire-climax vegetation types. The Whitewinged Flufftail is rare but its occurrence was regularly noted during the summer at four sites in Natal and the Transvaal. Habitat preferences and movement patterns were clarified, as was the bird's ecological segregation from the Redchested Flufftail. No conclusive evidence was found for breeding in South Africa and it is suggested that lack of suitable breeding habitat (possibly as a result of its being occupied by breeding Redchested Flufftails) may account for this. Some aspects of the bird's behaviour and calling were investigated. In view of this bird's threatened status and the continuing destruction of its wetland habitats, further surveys are urgently required to clarify the bird's status and the full extent of suitable habitat in South Africa, while a captive breeding programme is recommended to study breeding behaviour. The Buffspotted Flufftail inhabits a wide variety of forested and bushed habitats, and in Natal is a successful colonist of exotic vegetation in gardens. Its breeding biology, territorial and aggressive behaviour, and feeding ecology, were investigated in detail. It has regular seasonal movements in Natal, probably both altitudinal and coastal, although birds may remain throughout the year in areas where conditions are suitable. Seasonal departures are correlated with decreasing invertebrate food availability, while return time is largely governed by food availability, although cover development in exotic vegetation delayed recolonization at one site. The pair bond and the territory are maintained throughout the breeding season, and possibly throughout the year under suitable conditions. Adult mortality is probably high and the species' breeding strategy emphasises fecundity, this being achieved by a large clutch size, a very restricted period of parental care and rapid re-nesting. Juvenile mortality is high. The plumage, behavioural and vocal development of the young were studied in detail.