Browsing by Author "Crowe, Anna Aletta"

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    Aspects of the behaviour and ecology of White-fronted Sandplovers and Sanderlings on a South African sandy beach
    (1986) Crowe, Anna Aletta; Siegfried, Roy
    The dissertation comprises a general introduction, five chapters and a summary-synthesis which is designed to link the chapters into a cohesive account. Chapter 1 deals with the avian population of a southwestern Cape sandy shore and compares this population with those of sandy beaches in the eastern Cape and Natal. The abundance of birds and the estimated energy requirements of the avian populations in these three geographical areas increase during the austral summer, due to an influx of migrants from the northern hemisphere. The proportion of migrants to residents varies geographically, being greater in the southwestern Cape and Natal than in the eastern Cape. Chapter 2 summarizes information on the systematics, global distribution and morphology of two small shorebirds, the White-fronted Sandplover Charadrius marginatus and the Sanderling Calidris alba, which are identified in Chapter l as being dominant components of the southwestern Cape sandy shore avian population. Chapter 3 reports on the spatial and temporal use of the intertidal habitat by foraging White-fronted Sandplovers ·and Sanderlings. Interactions between these two species are discussed in the light of competition theory. The foraging ecology of the Sanderling and White-fronted Sandplover at Ouskip differed strikingly. Although both species exhibited a tidal cycle in foraging activities, rather than a diurnal cycle, White-fronted Sandplovers tended to feed during the latter half (i.e. mid to high tide), whereas Sanderlings fed during the first half (i.e. low to mid tide) of the tidal cycle. Both species' foraging activity also varied spatially and seasonally. White-fronted Sandplovers fed primarily in drier microhabitats above high tide level, and Sanderlings in wetter microhabitats near the water's edge. In Chapter 4, the size and structure of Sanderling flocks are described. The frequency distribution of flock sizes of wintering Sanderlings foraging on the sandy beach at Ouskip was bimodal, with a peak at small flock sizes and another at large flock sizes. It is hypothesized that large groups of Sanderlings consist of individuals searching for subterranean prey, and that small groups consist of subsets of these larger groups which have located food patches. Chapter 5 is an analysis of breeding periodicity in White-fronted Sandplovers in southern Africa, and focuses on the relationships between geographical and year-toyear variation in breeding activity and rainfall patterns, food availability and the possible effects of competition with migrant shorebirds. This species exhibits significant geographical variation in breeding season, and significant year-to-year variation within an area which has winter (May - August) rainfall. There was no year-to-year variation in breeding season within an area with summer (November - February) rainfall.
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    Standards of South African Senior Certificate Biology examinations : 1994 to 2007. Volume 1 : Chapters and references.
    (2012) Crowe, Anna Aletta; Laugksch, Rudiger C; Dunne, Tim
    Public examinations, such as the South African Senior Certificate (SC) examinations at the end of Grade 12, signal two messages to the society in which they operate: first, the competencies that are valued, that is, its standards; second, the required level of mastery in these competencies that are construed as indicators of success. The SC examinations certified successful students as competent to enter the workforce and, if they obtained a matriculation exemption, qualified them for admission to tertiary study. The SC was not a part of an explicit standards-based curriculum, and there is thus little understanding, but much public speculation, about the relationship between student achievement in the SC examinations, competency and standards. In an attempt to understand this relationship - with a particular focus on the role of standards - in the SC Biology examinations over a period of time, the answer to the following research question was sought: What did the SC Biology examinations in South Africa assess; did their focus change during the period 1994 to 2007; and, if so, what did this change mean?. Both in South Africa and internationally, "standards" is an often-used educational term, the meaning of which has become confused in the literature and by public use. In this study, a methodology to make explicit the standards inherent within the SC Biology examinations - and the relationship between standards and student achievement - was developed, described and applied.