Spelling suggestions: "subject:"birds -- bvehavior"" "subject:"birds -- cobehavior""
81 |
Habitat selection in the yellow-breasted chatJanuary 1979 (has links)
M. S.
|
82 |
Habitat selection in the yellow-breasted chatMcQuate, Grant Thomas January 1979 (has links)
During the spring and early summer of 1978, boundaries were determined for 19 yellow-breasted chat (<i>Icteria virens</i>) territories in southwestern Virginia. The gross structural characteristics of the vegetation found within these areas were analyzed. Each vegetation variable was regressed against territory size and against a measure of chat density. It was assumed that both smaller territories and territories having a greater number of territories surrounding them contained better quality habitat. Chats appear to choose their habitat on the basis of the total brushiness present. of several different components. This value may result from the summation In this study, bramble (<i>Rubus</i> spp.) cover and total shrub cover were the two major components involved. The vegetation contributing to the total brushiness value should minimally provide about 25% cover and average about 0.75 min height.
Increased greenbrier (<i>Smilax</i> spp.) cover is associated with better quality chat habitat. Presumably, it is indicative of the types of vegetation, such as thickets and open woods, which are characteristic of chat habitats. However, the measure of greenbrier cover seems limited in its ability to distinguish preferred chat habitat.
Chat territories may include wooded areas provided there is a fairly dense growth of vegetation below about 1.5 m. Generally, this situation would occur only in a woods with a reasonably open canopy. If only an edge of a woods bordering a brushy field is involved, side-lighting may be sufficient for the growth of ground-level vegetation, even if under fairly dense overstory vegetation. / M. S.
|
83 |
A test of factors affecting the foraging success of scarlet ibisUnknown Date (has links)
Wading bird foraging success is influenced by many different factors. From January to March 2008, I conducted a small-scale experiment with three captive Scarlet Ibis (Eudocimus ruber) at the Palm Beach Zoo, in West Palm Beach, Florida. Prey density and the presence of conspecifics were manipulated to test for a response by ibis in terms of prey capture rate. Mixed model analysis, when one prey type was available, showed that capture rate increased significantly with prey density and decreased with the presence of conspecifics. When two prey types were available, prey density and the presence of conspecifics had no effect on the capture rates of either prey type. Selectivity analysis revealed that ibis always selected for crayfish in mixed treatments. I hypothesize that the number of prey types available in a treatment played an important role in determining how fish density and the presence of conspecifics affected ibis foraging success. / by Rebecca A. Stanek. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
|
84 |
The neuroethology and evolution of nest-building behaviourHall, Zachary J. January 2014 (has links)
A surge of recent work elucidating a role for learning and memory in avian nest-building behaviour has challenged the long-standing assumption that nest building develops under genetic control. Whereas that work has been addressed at describing the cognitive mechanisms underpinning nest-building behaviour, almost nothing is known about either the neurobiological processes controlling nest building or the selection pressures responsible for the diversity in avian nest-building behaviour. Here, I sought to identify both the neural substrates involved in nest-building behaviour and some of those selection pressures. First, I used expression of the immediate early gene product Fos, an indirect marker of neuronal activity, to identify brain regions activated during nest-building behaviour in the brains of nest-building and control zebra finches (Taeniogypia guttata). I found that neural circuits involved in motor control, social behaviour, and reward were activated during nest building. Furthermore, I found that subpopulations of neurons that signal using the nonapeptides vasotocin and mesotocin and the neurotransmitter dopamine located within some of these neural circuits were also activated during nest building, suggesting these cell-signalling molecules may be involved in controlling nest-building behaviour. Next, I found that variation in the amount of folding in the cerebellum, a brain structure thought to be involved in manipulative skills, increased with increasing nest structural complexity, suggesting that the cerebellum is also involved in nest building. Finally, using evolutionary statistical models, I found support for the hypothesis that nest-site competition off-ground and increased predation pressure on the ground in Old World babblers (Timaliidae) led to the co-evolution of building domed nests on the ground. Here, then, I provide the first evidence of potential neural substrates controlling and selection pressures contributing to variation in nest-building behaviour.
|
85 |
Utilização de lâmpadas de LED em distintas intensidades luminosas e seus efeitos no desempenho e comportamento de frangos de corte / Use of LED lamps in different light intensities and their effects on the performance and behavior of broilersDias, Elisandro Rafael 23 April 2015 (has links)
O Brasil vem despontando no mercado avícola mundial, devido à alta qualidade de seus produtos e à grande variedade de cortes e industrializados, mostrando-se dinâmico, competitivo e disposto a adequar os processos produtivos às exigências deste segmento. Diversas práticas relacionadas ao manejo de frangos de corte têm sido implementadas visando a melhoria dos índices produtivos. Por isso, maiores cuidados em todas as fases de criação, acarretarão em melhores resultados alcançados nos índices zootécnicos e na qualidade final do produto, além do atendimento ao mercado consumidor. O controle ambiental é fundamental nas instalações, especialmente em relação ao sistema de iluminação que influencia diretamente no desempenho e comportamento das aves. O sistema de iluminação nos ambientes controlados tem sido revisto. As lâmpadas incandescentes normalmente utilizadas foram substituídas pelas lâmpadas fluorescentes, com isto novas tecnologias estão sendo propostas, como as lâmpadas de LED (Light Emitting Diode). As lâmpadas de LED possuem maior eficiência energética e maior durabilidade, visto que a luz emitida é fria, não dissipando energia em forma de calor. Além disso, a tecnologia dessas lâmpadas possibilita sua utilização no comprimento de onda preferencial pelas aves, ou seja, na cor da iluminação. Portanto, este estudo avaliou os efeitos de diferentes cores de lâmpadas de LED e intensidades luminosas sobre o desempenho e comportamento de frangos de corte. / Brazil is emerging in the world poultry market due to high quality of these products and the wide variety of cuts and industrialized, showing up dynamic, competitive and willing to adapt the industrial processes to the requirements of this segment. Various practices related to the management of broilers have been implemented aimed at improving production rates. Therefore, the greater the care at all stages of creation, the better the results achieved in the performance parameters and the final quality of the product, beyond the customer service market. Environmental control is fundamental premises, especially in relation to the lighting system that directly influences the performance and behavior of birds. The lighting system in controlled environments has been revised, incandescent bulbs normally used were replaced by fluorescent lamps with new technologies that are being proposed, such as LED lamps (Light Emitting Diode). LED bulbs are more energy efficiency and durability, as the light emitted is cold, not dissipating energy as heat. In addition to allowing the use in the preference wave length for broilers. Therefore, this study evaluated the effects of different colors of LED lamps and intensities on the performance and behavior of broilers.
|
86 |
Utilização de lâmpadas de LED em distintas intensidades luminosas e seus efeitos no desempenho e comportamento de frangos de corte / Use of LED lamps in different light intensities and their effects on the performance and behavior of broilersDias, Elisandro Rafael 23 April 2015 (has links)
O Brasil vem despontando no mercado avícola mundial, devido à alta qualidade de seus produtos e à grande variedade de cortes e industrializados, mostrando-se dinâmico, competitivo e disposto a adequar os processos produtivos às exigências deste segmento. Diversas práticas relacionadas ao manejo de frangos de corte têm sido implementadas visando a melhoria dos índices produtivos. Por isso, maiores cuidados em todas as fases de criação, acarretarão em melhores resultados alcançados nos índices zootécnicos e na qualidade final do produto, além do atendimento ao mercado consumidor. O controle ambiental é fundamental nas instalações, especialmente em relação ao sistema de iluminação que influencia diretamente no desempenho e comportamento das aves. O sistema de iluminação nos ambientes controlados tem sido revisto. As lâmpadas incandescentes normalmente utilizadas foram substituídas pelas lâmpadas fluorescentes, com isto novas tecnologias estão sendo propostas, como as lâmpadas de LED (Light Emitting Diode). As lâmpadas de LED possuem maior eficiência energética e maior durabilidade, visto que a luz emitida é fria, não dissipando energia em forma de calor. Além disso, a tecnologia dessas lâmpadas possibilita sua utilização no comprimento de onda preferencial pelas aves, ou seja, na cor da iluminação. Portanto, este estudo avaliou os efeitos de diferentes cores de lâmpadas de LED e intensidades luminosas sobre o desempenho e comportamento de frangos de corte. / Brazil is emerging in the world poultry market due to high quality of these products and the wide variety of cuts and industrialized, showing up dynamic, competitive and willing to adapt the industrial processes to the requirements of this segment. Various practices related to the management of broilers have been implemented aimed at improving production rates. Therefore, the greater the care at all stages of creation, the better the results achieved in the performance parameters and the final quality of the product, beyond the customer service market. Environmental control is fundamental premises, especially in relation to the lighting system that directly influences the performance and behavior of birds. The lighting system in controlled environments has been revised, incandescent bulbs normally used were replaced by fluorescent lamps with new technologies that are being proposed, such as LED lamps (Light Emitting Diode). LED bulbs are more energy efficiency and durability, as the light emitted is cold, not dissipating energy as heat. In addition to allowing the use in the preference wave length for broilers. Therefore, this study evaluated the effects of different colors of LED lamps and intensities on the performance and behavior of broilers.
|
87 |
História natural das aves em um parque urbano no Sudeste do Brasil / Natural history of the birds at urban park in a Southeastern BrazilD'Angelo, Giulia Bagarolli, 1982- 03 December 2014 (has links)
Orientador: Ivan Sazima / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-24T19:31:06Z (GMT). No. of bitstreams: 1
D'Angelo_GiuliaBagarolli_M.pdf: 26225858 bytes, checksum: a6b9b77b3bd66a3d80fd5d3157a3fef5 (MD5)
Previous issue date: 2014 / Resumo: O processo de urbanização no Brasil aumenta rapidamente e as áreas verdes fornecem refúgio para a fauna local, na qual as aves são o elemento mais evidente. Aves são agentes importantes de dispersão e polinização, controle de pragas, além de ciclagem de nutrientes e adubação do solo, exercendo diversos serviços ambientais. Embora essas funções possam ser vistas como tendo pouca importância no ambiente urbano, aves apresentam grande mobilidade, o que significa que suas funções podem ser transportadas de uma área verde para outra. Estudamos a história natural das aves em um parque urbano em Campinas, São Paulo. Alimentação, reprodução e repouso foram os focos deste estudo, além de outras atividades como higiene e conforto. As atividades alimentares que observamos seguem, em linhas gerais, o que está relatado na literatura sobre aves brasileiras. Entretanto, observamos alguns fenômenos não relatados ou pouco conhecidos Associações alimentares de aves piscívoras seguindo lontras em atividade de caça não estavam relatadas para América do Sul. Disputa por área de caça entre fêmeas de biguatinga Anhinga anhinga foi outra novidade relacionada à atividade alimentar, assim como a predação de um bivalve asiático invasor por aves aquáticas. A inclusão de uma categoria de presa (répteis) na dieta do sabiá Turdus leucomelas também representou uma novidade. As atividades reprodutivas que observamos no parque também seguem, em linhas gerais, as informações disponíveis na literatura sobre aves brasileiras. Todavia, observamos eventos pouco conhecidos ou não relatados na literatura. A corte do urubu Coragyps atratus está relatada para a América do Norte apenas. Também pouco conhecida é a disputa territorial "simbólica" entre fêmeas do pica-pau Colaptes melanochloros, comportamento relatado para machos de outras espécies. Outra novidade foi a pressão de predação pelo lagarto Salvator merianae em ninhos de aves que nidificam no chão ou em vegetação próxima a margem de lagoa. Atividades de higiene e conforto são bem conhecidas e ilustradas na literatura e acreditamos que não tenhamos observado algum comportamento de higiene e conforto que não esteja relatado, ainda que de passagem, para as aves brasileiras. Estudos sobre história natural de aves proporcionam um conhecimento mais adequado das relações entre as aves, o ambiente urbano e a população humana. Em parques e áreas verdes, as aves representam uma parcela de lazer para a população urbana. O número de observadores de aves aumenta no Brasil e, paralelamente, há uma valorização da conservação ambiental. Portanto, estudos em parques urbanos resultam em conhecimento sobre a avifauna, além de valorizar as áreas verdes e popularizar o conhecimento sobre as aves e a sua importância biológica / Abstract: The urbanization process in Brazil is quickly changing the landscape and so called green areas provide refuge for the local fauna, of which birds are the most conspicuous part. Birds are important agents of plant dispersal and pollination, pest control, as well as nutrient cycling and soil fertilizing, which result in ecosystem services. Although these functions may be viewed as having little or no importance in the urban landscape, birds are highly mobile and their functions may connect several green areas. We studied the natural history of birds in an urban park in Campinas, São Paulo, Southeastern Brazil. We focused on feeding, reproducing, and resting, besides preening and comfort activities. In general, feeding activities we observed followed what is published about Brazilian birds. However, we observed a few little known or until recently unpublished events. Feeding associations of piscivorous birds following foraging otters were unreported for South America. Contests for hunting area between females of the darter Anhinga anhinga was another novelty related to feeding activity, as well as the predation of an Asiatic invasive clam by water birds. Predation of reptiles by the thrush Turdus leucomelas was also a novelty. In general, reproductive activities we observed followed what is published for Brazilian birds. However, we observed a few little known or unpublished behaviors. For example the courtship of the vulture Coragyps atratus is reported for the North America only. Also little known is the territorial "symbolic" contest between females of the woodpecker Colaptes melanochloros, a behavior reported for males of other species. Another novelty was the predation pressure on birds that nest on the ground or bank vegetation by the large lizard Salvator merianae. Preening and comfort behaviors are well known and illustrated in literature and we believe that we did not record any behavior that is not reported in the literature on Brazilian birds, even if en passant. Studies on natural history of birds provide a better knowledge on the relationships between the birds, the urban landscape, and the human population. In urban parks and green areas, birds are part of leisure activities for urban people. The number of birdwatchers is increasing in Brazil and, at the same time, there is a growing awareness of environment conservation among people who are in contact with nature. Therefore, studies on natural history of birds in urban parks and other green areas result in knowledge of the bird fauna, besides increasing the intrinsic value of these environments and making available details of the life of birds and their biological significance / Mestrado / Biodiversidade Animal / Mestra em Biologia Animal
|
88 |
The effects of effort and day of exposure on imprintingVan Dyke, Jean Elizabeth 01 January 1974 (has links)
24 pairs of newly-hatched Leghorn chicks were randomly divided into 3 groups. Ss in one group followed a moving object for 30 min on Day 1 of life; Ss in another group followed for 30 min on Day 2; Ss in the remaining group followed for 15 min on Day 1 and 15 min on Day 2. One S in each pair followed by his own effort, while the other S rode behind the object in a transparent box. On Day 4, Ss were tested for the duration of following of the object. No important differences among groups were observed. On Day 6, Ss were tested for ability to discriminate between the original and a novel object, and for following the original. Active Ss scored significantly higher than passive Ss on all Day 6 tests; Ss trained on Day 2 scored significantly higher on the following than Ss trained on Day 1. The results suggest that the ‘law of effort’ may apply more to discrimination than to recognition of the imprinting object.
|
89 |
Trade-offs between the risks of predation and starvation in subtropical granivorous finchesBrandt, Miriam J. January 2007 (has links)
Animal community structures, life histories and individual foraging behaviour are all an outcome of a trade-off between competition for resources (and thus the risk of starvation) and survival (and thus the risk of predation). The relative importance of these factors however, differs between ecosystems, and especially when comparing temperate to tropical ones, we usually find marked differences. The seasonality of tropical ecosystems is much reduced compared to temperate ones, and weather conditions are less extreme. Accordingly tropical systems are characterised by higher species diversity, and different life history traits have been found between temperate and tropical birds. However, how the different environmental factors interact, and how predation and starvation risk vary to cause these differences still remains largely unknown. We studied the feeding behaviour of several granivorous Estrildid finches in scrub savannah habitat in central Nigeria to test how they respond to varying degrees of starvation and predation risk. During field observations and aviary experiments we investigated whether there is seasonal variation in the birds’ foraging behaviour correlating with the abundance of grass seeds and tested how they respond to different group sizes and differing distances from cover (representing a difference in predation risk). Further we also carried out field observation on the natural feeding behaviour of several closely related sympartic Estrildid finches to investigate inter-specific and seasonal differences in competition and microhabitat choice to see if this could explain their coexistence. Finally we studied habitat choice, movement behaviour and breeding biology of the potentially threatened endemic Rock Firefinch (Lagonosticta sanguinodorsalis) between the wet and the dry season via radio-tracking to establish its habitat requirements and gain the first information in its life history traits and population trends. We found little seasonal variation in the species’ foraging behaviour, and parameters that varied did not do so in a consistent manner. Thus, we found little evidence for a seasonal change in the risk of starvation. However, the abundance of several bird species varied widely between seasons and species leaving during periods of food shortage might have released competition for remaining resources. Birds did not show a strong response in their feeding behaviour with respect to cover in either intake rate or timing of feeding. However, intake rate increased with group size, which we believe to be due to scramble competition rather than risk dilution. We therefore conclude that predation did not shape the foraging behaviour of tropical granivorous passerines as markedly as that of temperate ones. Rock Firefinches were found to breed between the late rainy and the early dry season. They selected inselberg habitat, where most nests were found between rocky boulders. During the dry season, when water sources in inselberg habitat had dried out, they had to fly distances of up to 700 m to the gallery forest to get water and this led to the inclusion of more scrub savannah and gallery forest within their home ranges. Daily egg survival was 0.89 ± 0.03 calculated after the Mayfield analysis and most failing nests were depredated probably mainly by lizards. We suggest that in addition to nest predation, water availability might limit breeding time and thus reproductive output of Rock Firefinches. Predation risk did not seem to be of high importance in shaping the birds’ feeding behaviour because there was no seasonal variation in the risk of starvation. We found some suggestive evidence that competition might be important and it is likely that bird populations constantly stay close to carrying capacity. In contrast to temperate regions the need to conserve water might be of higher importance in shaping the birds’ feeding behaviour. High adult survival rates might be due to reduced seasonality in the risk of starvation thereby leading to reduced predation risk on adult birds. High nest predation might also be of higher importance in shaping the life history traits of tropical passerines, but at present this suggestion remains speculative. The results fit into the general framework that there is a trade-off between starvation and predation risk, and in the absence of starvation risk for some species in tropical areas, predation risk is also relatively unimportant.
|
90 |
The spatial ecology and roost site selection of fledging cape vultures (Gyps coprotheres) in the Eastern Cape, South AfricaMartens, Francis Rae, Downs, Colleen January 2018 (has links)
The Cape Vulture (Gyps coprotheres), a southern African endemic, is a species currently listed on the IUCN Red List as “Threatened” due to its 66-81% decline over the past 50 years. South Africa and Lesotho hold 90% of the global population, which are focused at two core areas, namely northern central South Africa and eastern South Africa. This species provides important ecological services yet faces numerous anthropogenic threats. An emerging threat in the south eastern part of South Africa is that of wind energy development. Understanding the movement and roosting behaviour of the Cape Vulture may mitigate potential collisions if areas of high use are avoided. Juvenile Cape Vultures, who naturally suffer high mortality rates, are known to forage extensively over a wider landscape and as a consequence may face a greater assortment of threats. The overall aim of this study therefore was to determine the ranging and roosting behaviour of juvenile Cape Vultures in the Eastern Cape Province, South Africa. In order to achieve this aim, i) the ranging behaviour and habitat use were determined and ii) roost sites and factors that influence roost site selection were determined. Using five juvenile Cape Vultures tagged with Global Positioning System (GPS/GSM) transmitters, home range sizes, distance travelled from the nest and habitat use were determined. Home range was determined through kernel density estimates and distance travelled from the nest was determined through the Euclidean distance. Habitat use was determined by overlaying the home range size onto a merged layer of all protected areas and the National Land Cover Database of South Africa. To determine roost sites, data from the tagged vultures were split into encamped and exploratory movements using a mixture model in a cluster analysis setting. Encamped movements were associated with roost sites. Roost density was determined around the natal colony using predetermined buffer sizes and a generalised linear mixed model (GLMM) fitted to the data. Conditions considered favourable for roost sites were based on previous research conducted on cliff-nesting species and a GLMM conducted. Juveniles increased their home range progressively for the first two months, then exhibited a rapid increase in size associated with dispersal from the colony. Distance from the nest increased rapidly following the dispersal period. Protected areas and woody vegetation were areas of preferred habitat. The highest density of roosts for juveniles was located within 20 km’s from the breeding colony and decreased further away. Roost sites that were favoured for juveniles and adult birds were those that were located close to colonies, had low accessibility to terrestrial predators and were in areas of high wind speed. The orientation of the cliff into the prevailing wind direction was also a determining factor. Roosting sites and foraging areas are important spatial determinants of Cape Vulture behaviour and the identification of such areas can help with conservation management. With the additional threat of wind development in areas highly utilised, wind farms located too close to colonies could have a devastating impact on the Cape Vulture population. Therefore, this study highlights the importance of conservation buffer zones as no-go areas for wind energy development around vulture colonies.
|
Page generated in 0.0513 seconds