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Behavioural and ecological interactions between Heliconius butterflies, their predators and host plantsDalbosco Dell'Aglio, Denise January 2016 (has links)
Heliconius butterflies exhibit Müllerian mimicry, in which two or more unpalatable species share a mutual advantage from having a common conspicuous colour pattern. These tropical butterflies have impressive visual signals, which are under conflicting selection pressures, as they are used in choosing potential mates and defending against visual predators through aposematic coloration. As both selection pressures are likely to be strong, different elements of the signal might be adapted for different receivers. Here, I combine sensory ecology with behavioural ecology to explain Heliconius colours signals of different co-mimic pairs. I explore how mimicry in Heliconius is perceived both from the perspective of predators and conspecifics, using visual abilities of both butterflies and birds. The different visual sensitivities of avian predators, H. erato females and males make them to perceive Heliconius coloration in different ways. My work suggests that having the ability to see in the ultra-violet light range enables higher discrimination between co-mimics both for birds and butterflies. Heliconius warning colours transmit a consistent signal across time of the day and habitat in a tropical forest for avian vision. In contrast through Heliconius vision there is evidence that patterns are more conspicuous in their own habitats. All these traits could facilitate communication between co-mimics and reduce the cost of confusion in courtship while still maintaining the advantages of Müllerian mimicry against predation. I conducted a field experiment to show that attack rates on a novel distasteful butterfly reduced over time, suggesting that Heliconius wing colouration can enhance aversion among predators. Finally, I have shown that Heliconius butterflies use leaf shape as a cue to approach their host plants, demonstrating the potential for Heliconius to drive negative frequency dependent selection on the leaf shape of their Passiflora host plants. Overall these results highlight ecological interactions between Heliconius butterflies, their predators and host plants.
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Influência de práticas de manejo e contexto da paisagem sobre a ocorrência de aves em plantio exótico de eucalipto / Influence of management practices and landscape context on bird occupancy in exotic eucalyptus plantationsMillan, Cristiane Honora 21 June 2013 (has links)
1. O manejo da vida silvestre em matrizes antropizadas, fora de reservas naturais, é importante para melhorar a eficácia de esforços conservacionistas que visam proteger e restaurar a biodiversidade. Desta forma, é fundamental entender as características da matriz que aumentam a adequabilidade do habitat para as espécies remanescentes e também avaliar as respostas das espécies à práticas de manejo alternativas. 2. Neste estudo utilizamos uma abordagem de modelagem hierárquica, que leva em conta o efeito de falhas de detectabilidade das espécies, para estimar o efeito de práticas de manejo adotadas dentro de talhões de plantios de Eucalyptus sobre a ocupação de aves. Nossos modelos incorporam características sítio-específicas, como tipo de prática de manejo e o contexto da paisagem em que se inserem cada unidade amostral. Também incorpora características espécie-específicas, em particular à sensibilidade das espécies aos distúrbios e estrato de forrageio. 3. O principal fator associado a diferenças na ocupação de aves dentro de nossa área de estudo é o tipo de pratica de manejo. A presença de árvores nativas dispersas e de sub-bosque em estágio inicial de sucessão dentro dos talhões está associada com um aumento na proporção de espécies do pool regional capaz de ocupar a matriz silvicultural. O contexto da paisagem teve um efeito relativamente menor sobre a ocupação de aves na área de estudo. 4. Síntese e Aplicação. A ocupação de aves está associada positivamente ao aumento da complexidade estrutural dentro dos talhões de eucalipto, as espécies respondem a retenção de árvores nativas dispersas e a presença de sub-bosque. Gerenciadores interessados em aumentar o valor conservacionista de plantios de Eucalyptus para as aves deveriam preservar as arvores maduras e adotar práticas que estimulem a regeneração do sub-bosque durante o preparo do local e rotação do plantio. / 1. Managing for wildlife in human-dominated matrices outside natural reserves has great importance to improve the efficacy of conservation efforts aiming to protect and restore biodiversity. As such, it is critical to understand which features of the matrix that enhance habitat suitability to the remaining species and also to evaluate species responses to alternative management practices. 2. We used hierarchical modeling to estimate the effect of stand level management practices adopted in Eucalyptus plantations on bird occupancy while accounting for species detection failure. Our models incorporate site- specific traits, such as management practice type and the landscape context of each sampling unit. It also incorporates species specific-traits, particularly species sensitivity to disturbance and species foraging stratum. 3. The major factor associated with differences in bird occupancy within our study site is the management practice type. Scattered native trees and early successional stage understory within mature stands was associated with an increase in the proportion of bird species from the regional pool that was able to occupy the silvicultural matrix. Landscape context had a relatively minor effect on bird occupancy in our study area. 4. Synthesis and applications. Bird occupancy is positively associated with increasing spatial heterogeneity within eucalyptus stands with species responding to the retention of native scattered trees and understory presence. Managers interested in improving the conservation value of Eucalyptus plantations to birds should preserve some existing trees and adopt practices that trigger understory regeneration during site preparation and stand rotation.
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Infecção experimental em frangos de corte com sorotipos de Salmonella spp. isolados de instalações avícolas e da avifauna selvagem /Sousa, Eliane de. January 2012 (has links)
Orientador: Karin Werther / Coorientador: Angelo Berchieri Júnior / Banca: Anna Monteiro Correia Lima Ribeiro / Banca: Ivens Gomes Guimarães / Banca: Marcelo Vasconcelos Meireles / Banca: Raphael Lucio Andreatti Filho / Resumo: Para a manutenção da avicultura brasileira e conservação dos seus altos índices de produção e exportação de produtos avícolas, são exigidas medidas de prevenção e controle de alguns agentes etiológicos nas granjas, como por exemplo, a Salmonella spp. O objetivo deste trabalho foi isolar e classificar Salmonella spp., em materiais colhidos de instalações avícolas, sunícolas e avifauna selvagem local, inocular posteriormente os sorotipos isolados em pintos de frangos de corte verificando sua patogenicidade.. Foram capturadas 36 aves selvagens de diferentes espécies nas instalações avícolas de uma granja integrada de frango de corte. Foi isolado Salmonella Heidelberg dos órgãos e conteúdo intestinal de um pica-pau-do-campo (Colaptes campestris),. As amostras positivas provenientes das aves de produção foram: cama aviária (Salmonella enterica subsp. enterica sorotipo 4,5,12:R:-; Salmonella Heidelberg; Salmonella Infantis), fezes de frangos de corte (Salmonella Heidelberg; Salmonella enterica subsp. enterica sorotipo 6,7:R:-; Salmonella enterica subsp. enterica sorotipo 4,5,12:R:-; Salmonella Tennessee); água (Salmonella Glostrup; Salmonella enterica subsp. enterica sorotipo 6,8:d:-;) e cascudinhos (Alphitobius diaperinus) encontrados na cama aviária (Salmonella Tennessee). Em fezes de suínos criados em galpões na mesma propriedade, foram isolados Salmonella Panama e Salmonella Typhimurium. Quanto à infecção experimental, em todos os nove grupos de aves foi observado entre o 3° dpi (dia pós-infecção) e o 12° dpi, fezes amolecidas no chão das gaiolas, ao redor da cloaca e na penugem das aves. Aos 15 e 21 dpi, os diferentes sorotipos de Salmonella foram isolados do conteúdo cecal, do baço e do fígado. Nas necropsias não foram encontradas alterações macro nem microscópicas relevantes / Abstract: For maintenance of the high levels of production in Brazil and the export of poultry products, preventive measures and control of some etiologic agents on farms, such as Salmonella spp., are required. The purpose of the present study was to initially investigate the presence of Salmonella spp.through bacterial culture in poultry houses materials collected from local poultry and wild birds and subsequently inoculate the isolated serotypes in broiler chicks and verify the effect on these. From the 36 wild birds captured in the poultry houses, Salmonella Heidelberg were isolated from the organs and intestinal contents from one woodpecker (Colaptes campestris) From the poultry houses the positive samples were: litter (Salmonella enterica subsp. enterica sorotipo 4,5,12:R:-; Salmonella Heidelberg; Salmonella Infantis), feces of broiler (Salmonella Heidelberg; Salmonella enterica subsp. enterica sorotipo 6,7:R:-; Salmonella enterica subsp. enterica sorotipo 4,5,12:R:-; Salmonella Tennessee), water (Salmonella Glostrup; Salmonella enterica subsp. enterica sorotipo 6,8:d:-;) and lesser mealworm (Alphitobius diaperinus) found in litter (Salmonella Tennessee). From the feces of swine also produced in sheds on the same farm were isolated Salmonella Typhimurium and Salmonella Panama. In the experimental infection done in nine avian groups (n=15) was observed between the 3rd dpi (days post-infection) and 12th dpi the presence of soft feces on the floor of the cages, around the cloaca and on feathers of the birds. On 15 and 21 dpi the different serotypes of Salmonella were isolated from the cecal contents, spleen and liver. At the necropsies weren't observed relevant macro or microscopic alterations / Doutor
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Breeding Bird Census to Compare Long-term Changes in the Avifauna of the Spruce-fir Forest on Mount Guyot, Great Smoky Mountains National Park 1967-2015Brooks, Kevin C 01 December 2015 (has links)
The high-elevation forests of the Southern Appalachian Mountains have been impacted and rearranged by a tiny introduced pest from Europe, known as the Balsam Woolly Adelgid (Adelges piceaea), creating a concern for conservation. Breeding bird censuses, along with botanical surveys, have been conducted periodically on an established 60-acre plot since 1967 on the virgin forested slopes of Mount Guyot, Great Smoky Mountains National Park, with the last census being completed in 2015. Breeding bird populations are shown to rise and fall in response to the forest’s changes over the last 48 years. Comparisons are made between all studies in order to assess how bird populations are being affected by the changed forest dynamics.
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Kia Whakamaramatia Mahi Titi : predictive measures for understanding harvest impacts on Sooty Shearwaters (Puffinus griseus)Clucas, Rosemary, n/a January 2009 (has links)
The sooty shearwater (also known as the muttonbird, Titi, Puffinus griseus) is a long-lived super-abundant, burrow nesting petrel, harvested by Rakiura Maori from breeding colonies, located in southern New Zealand. The harvest is culturally defining and enormously important for Rakiura Maori. The work in this thesis contributes to the Kia Mau te Titi Mo Ake Tonu Atu Research Project being undertaken by Rakiura Maori and the University of Otago, towards assessing ongoing sustainability of the harvest and future threats.
Analyses of eight muttonbirder harvest records spanning, 1938 to 2004, show that harvest rates demonstrate, systematic commonalities in seasonal patterns and broad-scale consistency in trends of chick abundance and quality across harvested islands. If co-ordinated and well replicated, harvest records offer Rakiura Maori a low-cost and effective monitoring tool of sooty shearwater reproductive success and long-term population abundance. Hunt tallies provide additional evidence of a dramatic reduction in sooty shearwater abundance from the late 1980s that was also detected by counts from boats off the western seaboard of the USA. A conservative estimate of overall decline in hunt success across diaries, for the period 1972 to 2004, is 1.89 % (CI₉₅ 1.14 to 2.65) per annum, a total reduction of 39.2%. The harvesting records show a sooty shearwater mortality event occurred just prior to the 1993-breeding season at the same time as a severe negative anomaly in both the Pacific Decadal Oscillation and Southern Oscillation Indices. The hunting diaries show a decoupling of chick size with harvest success in the early 1990s. This resulted from a decline in harvest success and an increase in its variability, while chick size remained correlated with changing chick abundance and maintained its pre-1990 average. Long- lived seabirds maintain high survival by skipping breeding and abandoning breeding attempts when oceanic conditions deteriorate, increasing variability in chick abundance is also evidence of pressure on adult survivorship. The multiple diaries confirm these were major demographic events not confined to a single island.
My survival estimates for The Snares and Whenua Hou were very high 0.952 (0.896-0.979) compared to earlier estimates for this species. Transience at the colonies is high due to the presence ofjuvenile and pre-breeding birds. Both naturally high survival and the large number of transient pre-breeders indicate sooty shearwater are more resilient to harvest than earlier survival models suggested. There was no evidence for directional change in sooty shearwater breeding phenology over 49-years of harvest. Climate fluctuation/change is therefore apparently not altering egg-laying. Peak fledging occurred fairly consistently in the 2nd of May (IQR = 2.91 days). Yearly variability in emergence occurs primarily due to provisioning and localized fledging conditions. Larger chick size was strongly correlated with delayed fledging and is consistent with the traditional ecological knowledge of the birders. There was no evidence for chicks becoming smaller or that years with starving chicks were more common, so increasing mismatch of breeding with optimal forage was not indicated.
The past proportion of birders over the last 20 years (1985 - 2005) has been ~2% all of Rakiura Maori. Approximately 376 birders participated in the 2006 season with an estimated of overall harvest intensity 19.4% (CI₉₅ = 13.8 - 24.2%) and a total catch of 381,000 (CI₉₅ = 262,257 - 487,186) chicks. This study found evidence that catch rates reduced with increasing birder competition partially mitigating effects on harvest pressure. The combined effects of potential climate change on bird abundance and increased harvester competition suggests that the proportion of Rakiura Maori whom choose to bird is likely to decrease as tallies reduce and cost recovery becomes more difficult. Rakiura Maori have for many years cherished and maintained their islands and implemented protective measures to safeguarded titi breeding habitat. Future harvest management will have additional issues to contend with, but Rakiura Maori are necessarily confronting these issues as the titi culture rests on the maintenance of their taonga. The information presented in this thesis shows that combining science and traditional knowledge is a powerful tool for managing harvest sustainability.
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Microbial infection of avian eggs : a threat to all synchronously incubating species? Case study of New Zealand's little blue penguin (Eudyptula minor) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Auckland, New ZealandBoyer, Anne-Sophie January 2010 (has links)
Microbial infection of eggs was originally investigated in terms of human health only. Recently, however, it was found that it can also cause early embryo mortality in birds, mainly through trans-shell infection prior to incubation. Trans-shell infection is highly dependent upon environmental conditions, egg temperature and egg properties such as shell quality and antimicrobial defences. Microbial infection of eggs is more likely to occur in synchronously incubating species as first laid eggs can be exposed for up to several days prior to full incubation. One example of a population that seems at particular risk of egg microbial infection is New Zealand’s little blue penguin (Eudyptula minor) from Tiritiri Matangi Island. This bird lays two eggs on average three days apart, and is believed to begin full incubation only after the second egg has been laid. Both eggs are laid in particularly humid and soiled nests and contain only low levels of lysozyme, an important antimicrobial protein. The aims of this study were therefore to 1) obtain a first examination of the rates of shell and trans-shell microbial infection of chicken eggs in New Zealand and assess the effects of cleaning on those rates, 2) investigate the role of microbes in hatching failure of little blue penguin eggs and 3) investigate other factors affecting little blue penguin egg viability. This study revealed that shell infection in chicken eggs significantly increased with exposure and significantly decreased with cleaning; however, trans-shell infection was only marginally affected by exposure and cleaning. On Tiritiri Matangi Island, Hauraki Gulf, New Zealand, nest type, egg order and shell cleaning did not affect hatching success, suggesting that nest conditions and microbial infection prior to incubation were not a major cause of egg mortality in this population. Temporary abandonment during incubation, however, was very frequent in the second half of the breeding season and fatal to most eggs. These temporary abandonments seemed to be caused by resource limitations, an aspect that should be investigated in future studies.
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Indirect effects of river regulation : consequences for landbirds of reduced numbers of aquatic insectsStrasevicius, Darius January 2007 (has links)
<p>Abstrakt: Jag har undersökt hur älvreglering påverkar mängden knott (Tvåvingar: <i>Simuliidae</i>) längs flera norrlandsälvar och vilka konsekvenser denna påverkan får för den landlevande fågelfaunan. Studien visar att utbyggnad av älvar har en negativ effekt på mängden knott. Det fanns sju gånger högre tätheter av knott längs "orörda älvar" jämfört med utbyggda älvar.</p><p>Skillnaden i antal knott mellan älvtyperna var mycket större för knotthanar än för knotthonor, vilket förklaras av att honorna är rörligare eftersom de flyger och letar efter blod. Knott lever av blod från ett flertal däggdjur och fåglar och visar en stor variation i värd-specificitet mellan olika arter. Jag fann en högre frekvens av haemosporida blod parasiter (<i>Leucocytozoon</i>) i fåglar längs "orörda" Vindelälven jämfört med den reglerade Umeälven. Detta mönster stämmer väl överens med tätheten fågelparasiterande knott som är lägre längs Umeälven. Knott attackerade främst värdar som var stora och vanliga. Fågelsamhällets sammansättning skiljde sig mellan orörda och utbyggda älvdalar. Tätheten av icke insektsätande fåglar tenderade att minska, efter häcksäsongen, längs orörda älvar medan den ökade längs utbyggda älvar. Den insektsätande fågeln svartvit flugsnappare (<i>Ficedula hypoleuca Pallas</i>) uppvisade större häckningsframgång längs orörda älvar jämfört med utbyggda älvar. Detta är förmodligen en effekt av den större mängden insekter som finns längs orörda älvar.</p> / <p>The effects of river regulation on blackfly (Diptera: <i>Simuliidae</i>) abundances and consequences for the avifauna in terrestrial environments were studied along multiple rivers in northern Sweden. I found that impoundment of rivers has detrimental effect to blackfly abundances. The densities of large-river breeding blackfly species were several-fold higher along free-flowing than along regulated rivers. The difference in abundances was much larger in males than blood-seeking females. Blackflies attacked a variety of mammalian and avian hosts and showed different levels of host-specificity between species. I found higher prevalence of haemosporidian blood parasites (<i>Leucocytozoon</i>) in birds along the free-flowing Vindel River in comparison to the regulated Ume River, where the lower densities of ornithophilic blackflies were reduced. Blood-seeking blackflies predominantly attacked large and/abundant hosts.</p><p>Assemblages of birds differed between valleys of regulated and free-flowing rivers. Densities of noninsectivorous birds tended to decrease along free-flowing rivers in the post-breeding season, but increased along regulated rivers at the same time. Insectivorous European pied flycatcher (<i>Ficedula hypoleuca Pallas</i>) showed greater fledging success along free-flowing than regulated rivers, which probably reflects the higher insect abundances found along freeflowing rivers.</p>
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Indirect effects of river regulation : consequences for landbirds of reduced numbers of aquatic insectsStrasevicius, Darius January 2007 (has links)
Abstrakt: Jag har undersökt hur älvreglering påverkar mängden knott (Tvåvingar: Simuliidae) längs flera norrlandsälvar och vilka konsekvenser denna påverkan får för den landlevande fågelfaunan. Studien visar att utbyggnad av älvar har en negativ effekt på mängden knott. Det fanns sju gånger högre tätheter av knott längs "orörda älvar" jämfört med utbyggda älvar. Skillnaden i antal knott mellan älvtyperna var mycket större för knotthanar än för knotthonor, vilket förklaras av att honorna är rörligare eftersom de flyger och letar efter blod. Knott lever av blod från ett flertal däggdjur och fåglar och visar en stor variation i värd-specificitet mellan olika arter. Jag fann en högre frekvens av haemosporida blod parasiter (Leucocytozoon) i fåglar längs "orörda" Vindelälven jämfört med den reglerade Umeälven. Detta mönster stämmer väl överens med tätheten fågelparasiterande knott som är lägre längs Umeälven. Knott attackerade främst värdar som var stora och vanliga. Fågelsamhällets sammansättning skiljde sig mellan orörda och utbyggda älvdalar. Tätheten av icke insektsätande fåglar tenderade att minska, efter häcksäsongen, längs orörda älvar medan den ökade längs utbyggda älvar. Den insektsätande fågeln svartvit flugsnappare (Ficedula hypoleuca Pallas) uppvisade större häckningsframgång längs orörda älvar jämfört med utbyggda älvar. Detta är förmodligen en effekt av den större mängden insekter som finns längs orörda älvar. / The effects of river regulation on blackfly (Diptera: Simuliidae) abundances and consequences for the avifauna in terrestrial environments were studied along multiple rivers in northern Sweden. I found that impoundment of rivers has detrimental effect to blackfly abundances. The densities of large-river breeding blackfly species were several-fold higher along free-flowing than along regulated rivers. The difference in abundances was much larger in males than blood-seeking females. Blackflies attacked a variety of mammalian and avian hosts and showed different levels of host-specificity between species. I found higher prevalence of haemosporidian blood parasites (Leucocytozoon) in birds along the free-flowing Vindel River in comparison to the regulated Ume River, where the lower densities of ornithophilic blackflies were reduced. Blood-seeking blackflies predominantly attacked large and/abundant hosts. Assemblages of birds differed between valleys of regulated and free-flowing rivers. Densities of noninsectivorous birds tended to decrease along free-flowing rivers in the post-breeding season, but increased along regulated rivers at the same time. Insectivorous European pied flycatcher (Ficedula hypoleuca Pallas) showed greater fledging success along free-flowing than regulated rivers, which probably reflects the higher insect abundances found along freeflowing rivers.
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Ecology of mallard ducklings on Lower Klamath National Wildlife Refuge, CaliforniaMauser, David M. 09 December 1991 (has links)
The ecology of female mallards (Anas platyrhynchos) and their
broods was studied during 1988-90 on Lower Klamath National Wildlife
Refuge, California. Survival of 127 radio-marked ducklings from 64
broods was 0.18 to 10 days of life, and 0.37 and 0.34 to fledging for
1988, 1989, and 1990, respectively. For the 3 years of the study,
49.2% of hens lost their entire brood; 81.2, 36.8, and 37.5% in 1988,
1989, and 1990, respectively. Ninety-three percent of mortality
occurred on or before 10 days of life. No significant differences were
detected in the proportion of radio-marked ducklings lost from early
hatched or late hatched nests. A variety of predators consumed radio-marked
ducklings; however, 49% of the cases of mortality were a result
of an unknown predator. During 1989 and 1990, 3 radio-marked ducklings
from 16 hens which appeared to lose their entire brood were fledged by
other brood hens, and of 29 radio-marked ducklings that reached 44 days
of life, 6 (20.7%) had joined other broods.
Movements, home range, and habitat use were determined for 27
radio-marked broods. Relocation movements (>1000 m in 24 hrs) occurred
in 12 of the 27 broods, primarily in the first week and after the
fourth week of life. In 1989, significantly fewer radio-marked
ducklings from broods hatching in permanent marshes survived to fledge
compared to those originating in seasonal wetlands. Mean size of home
ranges was 1.27 ± 0.47 km² and 0.62 ± 0.21 km² in 1989 and 1990,
respectively. Most habitat selection by brood rearing hens occurred at
the second order, (selection of home range area). Hens selected
seasonally flooded wetlands with a cover component and avoided open or
permanently flooded habitats.
Estimated recruitment (females fledged/adult female in the spring
population), proportional change in population size, and number of
fledged young varied markedly during the 3 years of the study.
Estimated recruitment was 0.31, 1.26, and 0.83 for 1988, 1989, and
1990, respectively. The estimated proportional change in population
size ranged from 0.73 in 1988 to 1.29 and 1.04 during 1989 and 1990,
respectively. Number of fledged young ranged from 915 in 1988 to 6,102
in 1989. Movements, habitat use, and survival of postbreeding radio-marked
mallard hens were also determined. From mid-April to early
August, 5,279 exposure days without the loss of a radio-marked hen were
tallied. Of the 4 hens which emigrated from the study area, all were
unsuccessful in rearing a brood. Unsuccessful hens moved to surveyed
areas north of the study area significantly sooner than successful
hens. Canals were the primary habitat utilized by postbreeding hens in
1988 while mixed seasonal and emergent permanent marsh were the most
frequently used habitats in 1989 and 1990. Open seasonal and mixed
seasonal marshes were the most frequently utilized habitats by
incubating hens. Radio-marked hens moved a mean distance of 1,350 m
from the nest to suspected feeding areas. / Graduation date: 1992
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The Framing of China's Bird Flu Epidemic by U.S. Newspapers Influencial in China: How the New York Times and The Washington Post Linked the Image of the Nation to the Handling of the DiseaseSong, Ning 07 August 2007 (has links)
This study conducted a framing research that analyzed coverage of the bird flu (avian flu) in China by two major American newspapers that are influential in China (The New York Times and Washington Post). The goal was to examine how these two prestigious newspapers frame the bird flu epidemic in China and how they represent the country in this international health crisis. This study employed textual analysis regarding the way bird flu news articles were framed in terms of problem definition, causal explanation, moral evaluation and solution recommendations in both newspapers. The study found the epidemic was framed as more than just a public health crisis. Multiple news frames were found in both newspapers' coverage of bird flu, depicting the event as a cultural, social and political crisis to the nation and to the world.
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