THE BAOBABS OF MADAGASCAR

Summary. The genus Adansonia (Bombacaceae) is reviewed, with particular reference to those species native to Madagascar. Their taxonomy, distribution, habitat, pollination, fruit-animal interactions, seed dispersal and economic importance are discussed.     

SEA-BIRDS AT LAGOS AND IN THE GULF OF GUINEA

Regular observations of sea-birds were made in the vicinity of Lagos, southwest Nigeria, between October 1967 and June 1971. Records in the Gulf of Guinea were obtained in April 1969 and, together with others from Ghana and Sierra Leone, were used to complement this study. While few large populations of sea-birds are supported, the diversity of species occurring at Lagos and over offshore deep water was great. The occurrence of nine species of sea-bird new to Nigeria was established or confirmed; most of these were also new to West Africa southeast of Gambia. Details are given of fluctuations in numbers these and a further 16 species.
All coastal habitats at Lagos supported a large population of immature Black Terns, and groups of immatures made up a high proportion of observations of other Palaearctic terns and of Royal Terns, which breed only in northwest Africa. In contrast, the Lesser Black-backed Gulls and Damara Terns reaching Lagos (from breeding grounds almost two continents apart) were mainly adults; both these species are amongst those showing a current increase in numbers. A pronounced spring passage was observed among species including Royal and Sandwich Terns, but adult movements in autumn were not elucidated. The occurrence of the European race of the Little Tern in southwest Nigeria was confirmed, it is at least a regular spring migrant. The frequency of vagrants in January and February was linked to local climate as much to general distribution. Brief comment is also given on immature plumages, and the growing exploitation and pollution of coastal waters.     

THE PELAGIC DISTRIBUTION OF SEA-BIRDS IN THE WESTERN INDIAN OCEAN

The present paper summarises observations made during the International Indian Ocean Expedition on board the R.R.S.' Discovery, from August to November 1963 and from February to September 1964 in the Indian Ocean north of 20° S and west of 70° E. In 1963 work was carried out in the Somali Basin. In 1964 a series of transects were made over the ocean, the main purpose of which was to investigate the system of equatorial currents and the changes in the sea associated with the onset of the Southwest Monsoon in May. The Tropical Indian Ocean is briefly described. Except for local concentrations, the surface layers are poor in nutrient salts and plankton. There is a seasonal reversal of winds and surface currents in the Arabian Sea, but seasonal changes become less marked further south. Previous ornithological observations in the western Indian Ocean are mostly confined to the Arabian Sea or to the island groups. Thus, existing information on the pelagic range of pantropical species is incomplete. Observations made on each transect across the Indian Ocean in 1964 are summarised and compared with oceanographic data collected at the same time. General conclusions are not possible on the basis of so little information, though there appeared to be some relationship between the distribution of certain species and wind or current belts. The only marked discontinuity recorded was a concentration of Puffinus pacificus and Gygis alba at the northern edge of the Equatorial Counter-current at 58° E in March. Observations made on transects that were repeated before and after the onset of the Southwest Monsoon suggested that Sterna fuscata concentrates in the equatorial region as the monsoon develops. In general, both plankton and sea-birds were more abundant at 58° E than at 67¹/₄° E. An analysis of the presence or absence of sea-birds during each observation period, which lasted an average of one hour, established the difference between pelagic species and those largely restricted to within 50 miles of their breeding stations. There was no evidence of any correlation with zooplankton abundance, though birds of all species taken together were commonest where flying-fish were most abundant and S. fuscata appeared to be commonest in cool-water areas with strong winds, i.e. the Trade-wind belts. It was not possible to sample the food organisms of sea-birds quantitatively. Sea-bird observations in the Indian Ocean more than 200 miles from the continental coasts are summarized and compared with previous observations. The little information collected in the Indian Ocean agrees with previous work in the Pacific Ocean, where sea-birds are commonest in areas of convergence, and not where local upwelling and an associated concentration of plankton occur, such as on the equator. This may be due to the fact that populations of organisms on which sea-birds feed develop or concentrate a considerable time after upwelling of nutrient-rich water occurs. Since few sea-birds were seen feeding, it seems likely that available food is scarce and that much time is required to locate areas where it is abundant. Finally, evidence is presented to indicate how some sea-bird species may avoid or reduce competition by feeding at different distances offshore, or in different geographical areas.     

THE CRESTED CUCKOOS OF SOUTH AFRICA

Boshoff, A. F. &; Palmer, N. G. 1980 Macro-analysis of prey remains from Martial Eagle nests in the Cape Province. Ostrich 51:7-13.

A total of 346 prey items, collected from nine Martial Eagle Polemaetus bellicosus nests in the Cape Province, was analyzed. The importance of e.g. Leporidae and Viverridae in the prey spectrum is emphasized. Young domestic small-stock appear to stand at least as much chance of predation by large eagles as does the natural prey of these birds. Nevertheless stock predation by territorial, mated Martial Eagles was only 8% in this study, with some, at least, probably taken as carrion. The validity of the analysis of prey remains collected from or below eagle nests is discussed.     

ADDITIONS AND SUPPLEMENTS TO THE MADAGASCAR AVIFAUNA

Langrand, O. & SINCLAIR, J.C. 1994. Additions and supplements to the Madagascar avifauna. Ostrich 65:302-310.

In order to update the data base on Madagascar birds, the literature is reviewed and museum records and unpublished data are taken into consideration. Records of unusual birds or species recorded for the first time in Madagascar are enumerated. For each new species the information associated with each record is presented, and an opinion is given if the record is acceptable or not. Twenty-two new species are proposed as additions to the list of Madagascar birds.