Academic literature on the topic 'Weaver-birds'

It is generally assumed that birds build nests according to a genetic ‘template’, little influenced by learning or memory. One way to confirm the role of genetics in nest building is to assess the repeatability of nest morphology with repeated nest attempts. Solitary weaver birds, which build multiple nests in a single breeding season, are a useful group with which to do this. Here we show that repeatability of nest morphology was low, but significant, in male Southern Masked weaver birds and not significant in the Village weavers. The larger bodied Village weavers built larger nests than did Southern Masked weavers, but body size did not explain variation in Southern Masked weaver nest dimensions. Nests built by the same male in both species got shorter and lighter as more nests were constructed. While these data demonstrate the potential for a genetic component of variation in nest building in solitary weavers, it is also clear that there remains plenty of scope in both of these species for experience to shape nest construction.

Birds harbour a wide array of other taxa in their nests or in their plumage, which either have an ectoparasitic or commensal relationship with the host. We report on the discovery of a cheliferid pseudoscorpion found in the plumage and nests of the sociable weaver bird (Philetairus socius) in southern Africa. The nests of these communal birds are the largest of any bird, and may contain up to 500 individuals. The pseudoscorpion is likely to have a mutualistic relationship with the birds, most likely preying on other small invertebrates in the nests. Molecular data derived from two populations of the pseudoscorpion found divergence levels of 1.1% in cytochrome oxidase 1 (CO1), and an analysis of CO1 and two rRNA genes (18S and 28S) found a close relationship with Chelifer and Parachelifer in the tribe Cheliferini, which is supported by the morphology of the male genitalia. The molecular analysis also suggests that Beierius may not belong to the Cheliferini. The pseudoscorpion found in association with the sociable weaver represents a new genus and species, Sociochelifer metoecus Harvey, sp. nov.

Abstract The article* aims to clarify the relations between the early versions of tale type ATU 575. Examining the range of Chinese accounts concerning various wooden birds, the author concludes that two groups can be distinguished. The first consists of stories about flying wooden kite-like birds that are not used as vehicles, while in the second, we deal with wooden birds that can carry people. Records belonging to the second group and evidently having their origin in Indian and Central Asian folk tradition appear later in China. An attempt is made to restore possible outlines of the tale type’s ancestral stories. The article states that the tale of an enamoured weaver in the Panchatantra evolves from the structure of such an ancestral story.

M.Sc.
The recognition of the occurrence, importance and effects of contaminants on food chains and ecosystems has led to the development of biomonitoring programmes that use indicator species to estimate the levels in other parts of the ecosystem. There has been an increased awareness of potential pollution of ecosystems in Gauteng, South Africa, because of increased formal and informal urbanization, industrialization and mining activities. It is essential to obtain clear indications of metal pollution cause-effect relationships at ecosystem level in order to carry out effective management of these ecosystems. The objective was to investigate the application of an ecotoxicologically-based investigation of metals in selected bird species as bioindicators of metal pollution of ecosystems in Gauteng. Three passerine species were used, the Southern Masked Weaver (Ploceus velatus), the Red Bishop (Euplectes orix) and the Red-billed Quelea (Quelea quelea). The sites were selected to represent a theoretical pollution gradient from severely contaminated wetlands in the Vaal Triangle, to moderately contaminated wetlands in the Witwatersrand and Pretoria. A nature reserve in North West Province was chosen as reference site. The sites were Rietvlei in Tshwane, Roodekrans and Olifantsvlei in Johannesburg, Holfontein in the Vaal Triangle and Barberspan in North West Province. Two sampling surveys were carried out, one in 2002 and one in 2005. Feathers were collected for metal analyses. Blood samples were collected for biomarker (oxidative stress and DNA damage) and haematological analyses. The samples were digested using the microwave destruction technique. The metal analyses were carried out using ICP-MS. Oxidative stress enzymes (reduced glutathione content and catalase activity) were analysed in plasma samples and DNA damage was evaluated in red blood cells using the average base-pair length comparisontechnique. Haematological studies were done on the blood samples. The results were compared between the sites and surveys. The levels of stress correlated well with the levels of metals in the feathers. Sites with higher metal levels had higher levels of organism stress. Thus the study showed that the feathers can indeed be used in biomonitoring. Internationally there is a trend to incorporate Ecological Quality Objectives (EcoQOs) into legislation, especially when dealing with metal contamination. Within the framework of EcoQOs developed for birds the monitoring of contaminants forms a specific category of EcoQOs. However, due to a lack of available data, Reference and Target Levels still need to be set. The development of EcoQOs is especially important at this stage in South Africa. The recently promulgated National Biodiversity Act (10 of 2004) specifically provides for the preparation of conservation plans for identified ecosystems that are important because of their goods and services that they provide. Since there is no management tool available at present to develop a suitable management plan, the setting of EcoQOs that are in line with international standards and practices will be of immeasurable value to implementing the Act. Feathers from museum specimens were used to determine the Reference Levels for the various metals in the feathers. The Target Levels were calculated from the Reference Levels. These were compared to the Current Levels and the EcoQOs were determined for the metal levels in the feathers in weaver in Gauteng, South Africa.
Prof. V. Wepener