No abstract

We describe a population of Village Indigobirds Vidua chalybeata on the Zambezi River that parasitizes the nests and mimics the songs of a novel host species, Brown Firefinch Lagonosticta nitidula, yet coexists with a population that mimics the usual host species of this indigobird, Red‐billed Firefinch L. senegala. Male indigobirds mimicking the song of L. nitidula are morphologically indistinguishable from those that mimic songs of the usual host, L. senegala. Likewise, nestling indigobirds in broods of L. nitidula and L. senegala are similar in having mouth markings that mimic the nestlings of L. senegala rather than those of the novel host. Molecular genetic evidence indicates that the host switch to L. nitidula has involved at least four different indigobird matrilines. Indigobirds that are associated with L. nitidula are genetically similar to the indigobirds associated with sympatric L. senegala, and not to the indigobirds associated with west African Bar‐breasted Firefinch L. rufopicta, the species that is most closely related to L. nitidula. Because field and experimental studies show that female indigobirds prefer males that mimic the songs of their own foster species, and females choose the same host to parasitize, the indigobirds reared by a novel host form a distinct breeding population. Taken together, behavioural, morphological and genetic evidence indicates a recent host switch by indigobirds in the Zambezi region from their old host L. senegala to a new host L. nitidula.

This study (1994) examines the distribution and abundance of puku (Kobus vardoni Livingstone) in Kasanka National Park (area=470 km2) Zambia, following five years of anti‐poaching control. The puku is an important ‘flagship’ species for the park. Most puku were confined to a limited number (n=19) of river floodplains and dambos (total area=20·29 km2) towards the centre of the park. Large areas of ‘suitable’ habitat contained few, if any animals. The total population was estimated to be 613 (confidence limits=414–967) with an average density of 35·93 km−2 on occupied sites. The population sex ratio was markedly biased towards females (mean=3·4 females to 1 male), but group sizes were similar to those recorded in other African studies. Male groups were on average (2·6), smaller than those of females (7·3). Males appeared to be particularly vulnerable to poaching. The distribution of puku reflected a patchy distribution of resources and a flexible social system. Puku numbers have increased two fold since the previous (1989) survey. Other species have faired less well. Further work is required to clarify dispersal mechanisms. Taylor's power law may provide a useful model for describing population dispersion. Kasanka is an important local refuge for this increasingly threatened species in Zambia. Metapopulation theory may be applicable to puku because of their ability to move between patches, during seasonal flooding.

No abstract

A new species of bathyergid mole-rat, Fukomys vandewoestijneae, is described from an area on the Zaïre-Zambezi watershed, centred on the Ikelenge pedicle in the NorthWestern province of Zambia. It is diagnosed by a unique combination of morphological (size, lack of clear headmarks), chromosomal (2n= 44) and DNA sequence characteristics. This medium-sized species belongs to the Giant mole-rat "F. mechowii" clade, which was hitherto considered monotypic. Its known distribution is limited to the Ikelenge pedicle of Zambia and adjacent areas in the Democratic Republic of Congo (DRC) and presumably Angola. Colonies of this social mole-rat were observed in the chanas (dambos), degraded miombo woodland and in villages. Although presumably sympatric in historical times with F. mechowii, no overlap in the species current distribution could be established. This local endemic species adds further evidence to the conservation importance of the two-pedicle region (Ikelenge pedicle (Zambia)ŰKatanga pedicle (DRC)).