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The breeding ecology of the South Island Fernbird in Otago wetlands
No full textFormat: xviii, 236 leaves: illustrations (some coloured), maps; 30 cm.The fernbird is a small inconspicuous passerine with relatively poor flying capabilities. It is found occupying areas with a generally dense cover of low vegetation from sea level to over 1000 m elevation. With the drainage of wetlands and the clearance of vegetation for farm development schemes or the planting of exotic pine forests, suitable habitat is diminishing at a rapid rate. Previous investigations on fernbirds have pointed out the relative stability and security of populations on remote islands and the vulnerability of small mainland populations in the face of habitat destruction.
The aims of the present study were to investigate the breeding ecology and habitat preferences of a population of fernbirds in one of New Zealand's few remaining extensive wetland areas and to determine whether management guidelines need to be implemented to ensure long-term survival.
To fulfill these aims I monitored the activities of individually colour-banded fernbirds over three complete breeding seasons. Sightings of recognizable individuals contributed to the mapping of territories. Nest sites were located and monitored. Information was collected on the length of the breeding season, the number of clutches produced during the season, the size of clutches, the duration of the incubation and nestling periods and an assessment of nesting success. The growth, development and feeding ecology of nestlings was also monitored in order to assess any differences with respect to brood-size, the prior nesting experience of parents or habitat quality.
Fernbird males are larger than females. Fernbirds are long-lived and sedentary, this combination apparently favouring the formation of long-term pair-bonds, possibly for life. Pairs occupy large territories that provide all of the resources for rearing young. Territory fidelity continues over several years, with a tendency for minor positional shifts to occur over the winter.
The preferred habitat is characterized by an assemblage of plant species that contribute to an extremely uneven canopy profile. Areas with significant amounts of surface water enhance this uneven profile. The preference of long-term residents for this habitat is reflected in the greater production of fledged young from this area.
Nest sites are selected for the degree of cover, but various factors influence the choice of location. Both sexes contribute to nest construction, incubation of eggs, brooding and feeding young. Nest initiation is highly asynchronous and the season can last more than six months.
The predation of nests by harriers, primarily during the nestling stage, is the most significant mortality factor. Introduced mammals account for a small proportion of losses, primarily in the drier areas of the wetland.
A comparison of the growth and development of nestlings from broods of various sizes indicated that there were some differences. Larger broods compromised a lower body weight at fledging for mature function in skeletal characters.
Despite the low levels of nesting success (30-40%) the long breeding season, the ability to produce more than one brood and the ability to increase clutch-size with no apparently greater risk, indicates that the population is capable of long-term survival. As long as there are no significant reductions to the size of the Lakes Waipori and Waihola wetlands or to the flow of water through the wetland, management policies are not required
A comparative ecological study of Pied and Black Stilts in South Canterbury.
No full textStilts Himantopus are long-legged waders of the Order Charadriiformes, Family Recurvirostridae. Two species occur in New Zealand, the Black Stilt H. novaezealandiae and the Pied Stilt H. himantopus leucocephalus, each of which has resulted from separate invasions of Himantopus stock from Australia. The early-invading form turned wholly melanic and became morphologically distinct from the ancestral stock in Australia. This early form (the Black Stilt) was widespread and common in New Zealand until late in the nineteenth century, but its taxonomic status and relationships with the Pied Stilt were never satisfactorily established, In the twentieth century the Black Stilt became restricted in numbers and in range, and today it is very rare, being confined mainly to the Upper Waitaki River Valley.
The aim of this study was to examine the present relationships of Pied and Black Stilts, particularly their ecological interactions. Field work was carried out from 1977 to 1980 mainly at Lake Tekapo where the two species overlapped in breeding range and where maximum sample sizes of Black Stilts could be obtained. The hypotheses proposed to account for the decline of the Black strlt were 1) competetive exclusion by the Pied Stilt, 2) introgressive hybridization with the Pied Stilt and 3) the Black Stilt's inability to adapt to man-induced changes in the environment.
To test these hypotheses I carried out studies of habitat utilization, and of feeding and nesting ecology of the two species. The feeding of Black Stilts was closely adapted to riverine habitats, whereas Pied Stilts utilized lentic habitats more heavily. Where individuals of the two species were present at one locality, the Black Stilts were territorially dominant. The breeding success of Black Stilts was significantly less than that of Pied Stilts, owing to the susceptibility of the former to predation by introduced mammals. Black Stilts nested on dry stream banks where the intensity of predation was very high. In addition, they were solitary nesters, had ineffective distraction displays, had a long fledgling period, and had an early start and often a late end to the breeding season, all of which increased their vulnerability. Pied Stilts exhibited opposite features, including nesting in very wet areas, particularly swamps, where reproductive success was high.
The two species are not reproductively isolated, but hybridize, despite positive assortative mating. Hybrids are fertile and vigorous. Through introgressive hybridization the Pied Stilt population has gained much new genetic material, to the extent that its members are subspecifically distinct from Pied Stilts in Australia.
The decline of the Black Stilt has resulted from its inability to adapt to man-induced changes (particularly the introduction of predators), coupled with introgressive hybridization with the Pied Stilt. Without continued active management, particularly predator exclusion, the population of Black Stilts will decline further, and those remaining will eventually be absorbed into the large Pied Stilt population
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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