Relevant bibliographies by topics / Bird density

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Academic literature on the topic 'Bird density'

Author: Grafiati
Published: 4 June 2021
Last updated: 19 February 2022

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Journal articles on the topic "Bird density"

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Iffiong, S. A., I. J. Fulani, and J. M. Olomu. "THE EFFECTS OF STOCKING DENSITY ON THE PERFORMANCE OF BROILER CHICKENS." Nigerian Journal of Animal Production 6 (January 19, 2021): 21–25. http://dx.doi.org/10.51791/njap.v6i.2652.

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THREE trials were conducted to determine the optimum stocking density for broiler chickens raised in a tropical environment In Trial 1, 100,67, 50,40, 34 and 29 birds were placed in duplicates in each pen with an area of 3.72 M2 to give stocking densities of 0.037, 0.056, 0.074, 0.093, 0.10 and 0 128 M2 per bird respectively. In Trial 2, stocking densities of 0.046, 0056, 0.064, 0.074, 0.083 and 0.093 M2 per bird were compared. Trial 3 involved studying the effects of providing equal feeder space (5cm/bird) or equal number of similar sized feeders (2 feeders per pen) when birds were stocked at floor spaces of 0.056, 0.064, 0.74, 0.083 and 0.093 sq meter per bird. Results showed that weight gain and feed consumption decreased, while total meat yield and net income per unit area increased, with increase in stocking rates. Feed efficiency, mortality and carcass dressing percentages were not significantly affected by the stocking rates. The effects of stocking densities on the performance of the birds were not altered by equalizing the feeder space per bird or by providing equal number of feeders per unit space. Management problems in terms of wetness of litter, feeding and watering were encountered with stocking densities of 0.037, 0.046 and 0.056 M2/ bird. Stocking rates of 0.083, 0.093, 0.10 and 0.128 M2 were uneconomic and did not produce superior performances to stocking densities of 0.064 or 0.074 M2/bird. On the basis of the results, floor spaces of 0.064 or 0.074 M2 per bird may be recommended as the optimum for broiler chickens raised in the tropics. The feeder space at these optimum stocking rates need not be more than 5cm per bird.
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Loe, Leif Egil, Atle Mysterud, Audun Stien, Harald Steen, Darren M. Evans, and Gunnar Austrheim. "Positive short-term effects of sheep grazing on the alpine avifauna." Biology Letters 3, no. 1 (November 21, 2006): 110–12. http://dx.doi.org/10.1098/rsbl.2006.0571.

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Abstract Grazing by large herbivores may negatively affect bird populations. This is of great conservation concern in areas with intensive sheep grazing. Sheep management varies substantially between regions, but no study has been performed in less intensively grazed systems. In a fully replicated, landscape scale experiment with three levels of sheep grazing, we tested whether the abundance and diversity of an assemblage of mountain birds were negatively affected by grazing or if grazing facilitated the bird assemblage. Density of birds was higher at high sheep density compared with low sheep density or no sheep by the fourth grazing season, while there was no clear effect on bird diversity. Thus, agricultural traditions and land use politics determining sheep density may change the density of avifauna in either positive or negative directions.
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Perkins, Genevieve C., Amanda E. Martin, Adam C. Smith, and Lenore Fahrig. "Weak Effects of Owned Outdoor Cat Density on Urban Bird Richness and Abundance." Land 10, no. 5 (May 10, 2021): 507. http://dx.doi.org/10.3390/land10050507.

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Domestic cats (Felis catus) are ubiquitous predators of birds in urban areas. In addition to the lethal effect of predation, there can also be sublethal, negative effects of domestic cats on individual birds. These effects have led to the inference that reducing outdoor cat densities would benefit urban bird communities. Here we estimate the likely result of policies/programs designed to reduce densities of owned outdoor cats in urban areas, estimating relationships between bird richness/abundance and cat densities across 58 landscapes in Ottawa, Ontario, Canada. We estimate that we would most likely observe one additional bird species, and 0.003 additional individuals per species, if policies/programs reduced owned outdoor cat densities to zero in an average landscape in Ottawa (with 130.2 cats/km2). However, these effects of cat density on birds were uncertain, with 95% confidence intervals crossing zero. Our findings—in combination with those of previous studies—suggest a need for research to resolve the apparent disconnect between the strong, negative effects of cats on individual urban birds and the weak, uncertain effects of cats on bird populations. Although measures that reduce owned outdoor cat densities are justified based on the precautionary principle, evidence to date does not support prioritizing these measures over those addressing threats that have consistently strong effects on bird populations.
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Shao, Quan, Yan Zhou, Pei Zhu, Yan Ma, and Mengxue Shao. "Key Factors Assessment on Bird Strike Density Distribution in Airport Habitats: Spatial Heterogeneity and Geographically Weighted Regression Model." Sustainability 12, no. 18 (September 4, 2020): 7235. http://dx.doi.org/10.3390/su12187235.

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Although the factors influencing bird strikes have been studied extensively, few works focused on the spatial variations in bird strikes affected by factors due to the difference in the geographical environment around the airport. In this paper, the bird strike density distribution of different seasons affected by factors in a rectangular region of 800 square kilometers centered on the Xi’an Airport runway was investigated based on collected bird strike data. The ordinary least square (OLS) model was used to analyze the global effects of different factors, and the Geographically Weighted Regression (GWR) model was used to analyze the spatial variations in the factors of bird strike density. The results showed that key factors on the kernel density of bird strikes showed evident spatial heterogeneity and the seasonal difference in the different habitats. Based on the results of the study, airport managers are provided with some specific defense measures to reduce the number of bird strikes from the two aspects of expelling birds on the airfield area and reducing the attractiveness of habitats outside the airport to birds, so that achieve the sustainable and safe development of civil aviation and the ecological environment.
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Lovász, Lilla, Fränzi Korner-Nievergelt, and Valentin Amrhein. "Grazer density and songbird counts in a restored conservation area." PeerJ 9 (January 5, 2021): e10657. http://dx.doi.org/10.7717/peerj.10657.

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Grazing by large herbivores is increasingly used as a management tool in European nature reserves. The aim is usually to support an open but heterogeneous habitat and its corresponding plant and animal communities. Previous studies showed that birds may profit from grazing but that the effect varies among bird species. Such studies often compared bird counts among grazed areas with different stocking rates of herbivores. Here, we investigated how space use of Konik horses and Highland cattle is related to bird counts in a recently restored conservation area with a year-round natural grazing management. We equipped five horses and five cattle with GPS collars and correlated the density of their GPS positions on the grazed area with the density of bird observations from winter through the breeding season. We found that in the songbirds of our study site, both the overall density of bird individuals and the number of species increased with increasing density of GPS positions of grazers. Correlations of bird density with horse density were similar to correlations with cattle density. Of the eight most common songbird species observed in our study area, the Eurasian Skylark and the Common Starling had the clearest positive correlations with grazer density, while the Blackbird showed a negative correlation. Skylarks and Starlings in our study area thus seem to profit from year-round natural grazing by a mixed group of horses and cattle.
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Hager, Stephen B., Heidi Trudell, Kelly J. McKay, Stephanie M. Crandall, and Lance Mayer. "Bird density and mortality at windows." Wilson Journal of Ornithology 120, no. 3 (September 2008): 550–64. http://dx.doi.org/10.1676/07-075.1.

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Omotoriogun, Taiwo Crossby, Joseph Daniel Onoja, Talatu Tende, Shiiwua Manu, and Ulf Ottosson. "Density and diversity of birds in the wetlands of Yankari Game Reserve Bauchi Nigeria." Journal of Wetlands Ecology 5 (December 28, 2011): 48–58. http://dx.doi.org/10.3126/jowe.v5i0.4778.

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The biological, chemical, and physical operations and attributes of wetlands are vital in facilitating food resources, water, and shelter, which many terrestrial bird and waterbird species rely on for their daily requirments. Wetlands in Yankari Game Reserve, Nigeria are key stone ecosystem that provides a stopover, breeding and/or foraging platform for migratory and resident birds. This study determined the density and diversity of birds in the wetlands of Yankari Game Reserve. Ten wetlands within the reserve were identified and surveyed. The sizes (kilometer square) and isolation distances (kilometer) of the wetlands were measured (using GPS and Map Source) to determine their effects on bird density and diversity. Point count survey method was used to count birds. One hundred and twenty three species of birds belonging to 51 families were recorded in the wetlands. Significant patterns in the densities of birds were observed across the wetlands (Kruskal-Wallis H, X2=167.116, P=0.001) and also sizes of wetlands (Wilcoxon test: Z= -2.803, P=0.005). There was differences in mean number of birds in survey time (Kruskal-Wallis, X2=15.784, P=0.045). Evenings were probably most preferred in bird-wetland utilization. Key words: Density; Diversity; Yankari ecosystem; Wetland utilization DOI: http://dx.doi.org/10.3126/jowe.v5i0.4778 J Wet Eco 2011 (5): 48-58
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Asaniyan, E. K., and V. O. Akinduro. "Impact of stocking density on the rearing environment and growth performance of broiler chicken." Nigerian Journal of Animal Production 47, no. 6 (February 28, 2021): 65–81. http://dx.doi.org/10.51791/njap.v47i6.2875.

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The consequence of high stocking density in commercial production of broiler chickens under the changing climate could predispose the chickens to adverse conditions. Therefore, this study was conducted to investigate the influence of stocking density on the rearing environment and performance of broiler chicken. Ninety (90) one day-old chicks of Arbor acre breed were used as experimental units in the trial that lasted eight (8) weeks. The bird were randomly assigned to three treatments of stocking densities 5, 10 and 15 birds/m2 with three replicates per treatment. The birds were raised in deep litter system bedded with woodshaving at 1 m2 per replicate. They were fed ad libitum with commercial broiler diets with drinking water supplied without restrictions. The meteorological data (Temperature and Relative Humidity) within the pen were obtained using the Maxims thermocron i-button Temperature and Humidity sensors and a stand-alone automated weather station was deployed outside the pen house which measured Temperature and Relative humidity parameters within the premises (Figure 1c), which were programmed to measure at 10 minutes sampling interval. Data collected were on daily ambient temperature and relative humidity, feed intake, water intake, weight gain and computed feed conversion ratio. The temperature of the broiler pens was found inversely related to its relative humidity across the treatments with relative fluctuations as the birds grow. Temperature within the pens (ambient temperature) increased with the stocking densities; stocking density 15 birds/m2 (25.94±0.125oC -31.79±0.360oC) being the hottest while 5 birds/m2 (25.47±0.136oC - 31.43±0.353oC ) was the least. Birds at stocking density of 5 birds/m2 (90.00g/bird/week – 2197.78g/bird/week) performed better in terms of growth and followed by those of 10 birds/m2 (95.00g/bird/week – 2018.52g/bird/week). Stocking densities of 15 birds/m2 (84.19g/bird/week – 1907.44g/bird/week) recorded the lowest weight gain. The combine influence of weather parameters (temperature and relative humidity) in bringing about growth of the birds diminishes as the stocking density increases. There was virtually no significant influence of the stocking densities on weekly mean temperature and relative humidity in the broiler chicken pens throughout the period of the study. Therefore, for eight weeks rearing period under any of the stocking density levels, fatality of weather modification could be prevented within the rearing environment through provision of adequate ventilation. La conséquence de la forte densité d'élevage dans la production commerciale de poulets de chair dans le climat changeant pourrait prédisposer les poulets à des conditions défavorables. Par conséquent, cette étude a été menée pour étudier l'influence de la densité d'élevage sur l'environnement d'élevage et les performances des poulets de chair. Quatrevingt-dix (90) poussins d'un jour de race 'Arbor acre' ont été utilisés comme unités expérimentales dans l'essai qui a duré huit (8) semaines. Les oiseaux ont été assignés auhasard à trois traitements de densités de peuplement de 5, 10 et 15 oiseaux / m2 avec trois répétitions par traitement. Les oiseaux ont été élevés dans un système de litière profonde recouvert d'un rasage de bois à 1 m2 par répétition. Ils ont été nourris ad libitum avec des régimes commerciaux pour poulets de chair avec de l'eau potable fournie sans restrictions. Les données météorologiques (température et humidité relative) à l'intérieur du stylo ont été obtenues à l'aide des capteurs de température et d'humidité 'Maximsthermocron i-button' et une station météorologique automatisée autonome a été déployée à l'extérieur de l'enclos qui mesurait les paramètres de température et d'humidité relative dans les locaux (Figure 1c), et ils ont été programmés pour mesurer à 10 minutes d'intervalle d'échantillonnage. Les données recueillies concernaient la température ambiante quotidienne et l'humidité relative, la consommation alimentaire, la consommation d'eau, le gain de poids et le taux de conversion alimentaire calculé. La température des enclos a été trouvée inversement proportionnelle à son humidité relative pendant les traitements avec des fluctuations relatives à mesure que les oiseaux grandissent. La température à l'intérieur des enclos (température ambiante) augmentait avec les densités de stockage ; densité de peuplement 15 oiseaux / m2 (25,94 ± 0,125 ° C -31,79 ± 0,360 ° C) étant le plus chaud tandis que 5 oiseaux / m2 (25,47 ± 0,136 ° C -31,43 ± 0,353 ° C) était le moins. Les oiseaux ayant une densité de peuplement de 5 oiseaux / m2 (90,00 g / oiseau / semaine - 2197,78 g / oiseau / semaine) ont obtenu de meilleurs résultats en termes de croissance et suivis par ceux de 10 oiseaux / m2 (95,00 g / oiseau / semaine - 2018,52 g / oiseau / semaine). Des densités de peuplement de 15 oiseaux / m2 (84,19 g / oiseau / semaine - 1907,44 g / oiseau / semaine) ont enregistré le gain de poids le plus faible. L'influence combinée des paramètres météorologiques (température et humidité relative) dans la croissance des oiseaux diminue au fur et à mesure que la densité d'élevage augmente. Il n'y avait pratiquement aucune influence significative des densités de peuplement sur la température moyenne hebdomadaire et l'humidité relative dans les enclos de poulets de chair pendant toute la période de l'étude. Par conséquent, pendant une période d'élevage de huit semaines, quel que soit le niveau de densité de peuplement, la mortalité due aux modifications climatiques pourrait être évitée dans l'environnement d'élevage grâce à une ventilation adéquate.
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Manhães, MA, and MM Dias. "Spatial dynamics of understorey insectivorous birds and arthropods in a southeastern Brazilian Atlantic woodlot." Brazilian Journal of Biology 71, no. 1 (February 2011): 1–7. http://dx.doi.org/10.1590/s1519-69842011000100003.

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Spatial distribution and spatial relationships in capture rates of understorey insectivorous birds and density of arthropods were investigated in a patch of upper montane rain forest in Minas Gerais state, southeastern Brazil, from January to December 2004. The composition of the arthropod fauna collected was similar to that reported for other tropical forests, with predominance of Araneae, Coleoptera, Hymenoptera and Hemiptera non-Heteroptera. A total of 26 bird species were captured, among which the more common were Dysithamnus mentalis, Conopophaga lineata, Platyrinchus mystaceus, Basileuterus culicivorus and Sclerurus scansor. Variation in the bird capture rates among sampling net lines were not correlated with arthropod density. Rather, individual analyses of some bird species suggest that spatial distribution of understorey insectivorous birds is better explained by habitat type.
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Aronson, Myla F. J., Frank A. La Sorte, Charles H. Nilon, Madhusudan Katti, Mark A. Goddard, Christopher A. Lepczyk, Paige S. Warren, et al. "A global analysis of the impacts of urbanization on bird and plant diversity reveals key anthropogenic drivers." Proceedings of the Royal Society B: Biological Sciences 281, no. 1780 (April 7, 2014): 20133330. http://dx.doi.org/10.1098/rspb.2013.3330.

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Urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. However, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. Here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). We found that the majority of urban bird and plant species are native in the world's cities. Few plants and birds are cosmopolitan, the most common being Columba livia and Poa annua . The density of bird and plant species (the number of species per km 2 ) has declined substantially: only 8% of native bird and 25% of native plant species are currently present compared with estimates of non-urban density of species. The current density of species in cities and the loss in density of species was best explained by anthropogenic features (landcover, city age) rather than by non-anthropogenic factors (geography, climate, topography). As urbanization continues to expand, efforts directed towards the conservation of intact vegetation within urban landscapes could support higher concentrations of both bird and plant species. Despite declines in the density of species, cities still retain endemic native species, thus providing opportunities for regional and global biodiversity conservation, restoration and education.
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Dissertations / Theses on the topic "Bird density"

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Sergio, Fabrizio. "Factors affecting habitat selection,density and productivity in the black kite (Milvus migrans)." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269482.

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Munyenyembe, F. E., and n/a. "Bird density and species richness in suburban Canberra, Australia : relationships with street vegetation, age of suburb and distance from bird source areas of native vegetation." University of Canberra. Applied Science, 1985. http://erl.canberra.edu.au./public/adt-AUC20061027.115542.

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Hulme, Mark F. "The density and diversity of birds on farmland in West Africa." Thesis, St Andrews, 2007. http://hdl.handle.net/10023/424.

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Johnston, Christine Ninette. "Ecological and Behavioral Impacts of Snag Density on Cavity-Nesting Birds in the Oak Savanna." Bowling Green State University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1180531111.

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Wenzel, Dawn Nicole. "Comparison of avian species diversity and densities on non-mined and reclaimed surface-mined land in east-central Texas." Thesis, Texas A&M University, 2006. http://hdl.handle.net/1969.1/4202.

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Surface mining often changes the native landscape and vegetation of an area. Reclamation is used to counter this change, with the goal of restoring the land to its original pre-mined state. The process of reclamation creates early successional-stage lands, such as grasslands, shrublands, and wetlands, attracting new plant and animal species to the area. I compared avian species density (number of individuals/ha), diversity (H'), and richness (number of species/ha) on reclaimed and non-mined lands at TXU's Big Brown Mine in Fairfield, Texas. I also compared my results to those of a previous study conducted 25 years earlier. Avian counts were conducted using a fixedradius point-count method on 240 points placed in four different vegetation types and in four land-age groups (time since being reclaimed). Vegetation was measured both locally, and at a landscape level. Overall bird species density did not exhibit a clear relationship on non-mined versus reclaimed land. Overall bird species diversity was greater on non-mined lands, whereas overall species richness was greater on reclaimed lands. My results demonstrated a lower mean/point bird density and higher mean/point bird diversity than were found 25 years earlier. Different nesting guilds occurred on the reclaimed lands than occurred on the non-mined lands. Results suggested different species were attracted to the several successional stages of reclaimed lands over the nonmined lands, which consisted of climax vegetation. The different successional stages of reclaimed lands increased overall diversity and richness of the landscape as a whole. Five bird species of conservation concern were observed in the study, all of which occurred on reclaimed land. Four of the five species primarily occurred on reclaimed lands. Future land management should include conserving different successional-stage lands to increase overall biotic diversity and richness of mined land, preserving reclaimed habitat for species of concern, and educating future private landowners on the importance of maintaining vegetative and bird species diversity.
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Coetzee, Bernard W. T. "Implications of global change for important bird areas in South Africa." Diss., University of Pretoria, 2008. http://hdl.handle.net/2263/29591.

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The Important Bird Areas (IBAs) network of BirdLife International aims to identify sites that are essential for the long-term conservation of the world’s avifauna. A number of global change events have the potential to negatively affect, either directly or indirectly, most bird species, biodiversity in general and associated ecological processes in these areas identified as IBAs. To assist conservation decisions, I assessed a suite of ten landscape scale anthropogenic pressures to 115 Important Bird Areas (IBAs) in South Africa, both those currently placing pressures on IBAs and those that constitute likely future vulnerability to transformation. These threats are combined with irreplaceability, a frequently used measure of conservation importance, to identify the suite of IBAs which are high priority sites for conservation interventions: those with high irreplaceability and are highly vulnerable to anthropogenic threats. A total of 22 (19%) of the South African IBAs are highly irreplaceable and are highly vulnerable to at least some of the pressures assessed. Afforestation, current and potential future patterns of alien plant invasions affect the largest number of highly irreplaceable IBAs. Only 9% of the area of highly irreplaceable IBAs is formally protected. A total of 81 IBAs (71%) are less than 5% degraded or transformed. This result, together with seven highly irreplaceable IBAs found outside of formally protected areas with lower human densities than expected by chance provides an ideal opportunity for conservation interventions. However, all the pressures assessed vary geographically, with no discernible systematic pattern that might assist conservation managers to design effective regional interventions. Furthermore, I used the newly emerging technique of ensemble forecasting to assess the impact of climate change on endemic birds in relation to the IBAs network. I used 50 endemic species, eight bioclimatic envelope models, four climate change models and two methods of transformation to presence or absence, which essentially creates 2400 projections for the years 2070-2100. The consensual projection shows that climate change impacts are very likely to be severe. The majority of species (62%) lose climatically suitable space and 99% of grid cells show species turnover. Five species lose at least 85% of climatically suitable space. The current locations of the South African Important Bird Areas network is very likely ineffective to conserve endemic birds under climate change along a “business a usual” emissions scenario. Many IBAs show species loss (41%; 47 IBAs) and species turnover (77%; 95 IBAs). However, an irreplaceability analysis identified mountainous regions in South Africa as irreplaceable refugia for endemic species, and some of these regions are existing IBAs. These IBAs should receive renewed conservation attention, as they have the potential to substantially contribute to a flexible conservation network under realistic scenarios of climate change. Considering all the global change threats assessed in this study, the Amersfoort-Bethal-Carolina District and the Grassland Biosphere Reserve (IBA codes: SA018; SA020) are the key IBAs in South Africa for conservation prioritisation.
Dissertation (MSc)--University of Pretoria, 2008.
Zoology and Entomology
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Hjernquist, Mårten B. "Living in a Variable Environment : Reproductive Decisions in Wild Bird Populations." Doctoral thesis, Uppsala universitet, Zooekologi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9464.

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In nature, environments are often variable and heterogeneous influencing ecological and evolutionary processes. This thesis focus on how animals interact with their environment and how that affects the reproductive decisions they make. Using empirical data collected from wild collared flycatcher populations, experiments and molecular approaches I try to unveil some of these relationships and the evolutionary, ecological and conservation implications of these findings are discussed. Firstly, collared flycatchers were shown to use breeding densities of their own and other species using similar resources when assessing costs and benefits associated to breeding in specific habitats. However, species will vary in how informative they are, and the worst competitor – with whom you overlap most in resources needs – also provides the best source of information. Collared flycatcher parents will also benefit differentially from investments in sons and daughters due to habitat characteristics and dispersal differences between the sexes. Here, I show that they will produce more of the sex that will give the highest expected fitness return given the environment they are in. These results also provide a reciprocal scenario to Clark's (1978) classical study of sex ratio adjustment in relation to local resource competition (LRC), as more of the natal philopatric sex is produced when LRC is low. Secondly, the effect of elaborated ornaments on paternity in the socially monogamous collared flycatcher was shown to be of more importance in areas where the intensity of intra- and intersexual conflicts are expected to be elevated. Hence, ornamentation by environmental interactions determines paternity, illustrating that sexual selection through extra-pair paternity is context dependent. Finally, even though the collared flycatcher populations that this thesis is based on have been studied on their breeding grounds for more then 25 years, we know little of where they are when they are not breeding. Here, stable isotope signatures in winter-grown feathers suggests that they may spend their winter with their breeding ground neighbours and do so repeatedly over years. Differences between breeding populations at this small scale should have many impactions for evolutionary and ecological processes as it will, for example, determine with whom individuals interact throughout their life.
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Aberle, Matthew Allen. "Effects of Bird Feeder Density on the Behavior and Ecology of a Feeder-Dependent Songbird: Patterns and Implications for Disease Transmission." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85045.

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Anthropogenic resource provisioning of wildlife has increasingly been hypothesized to alter pathogen spread. Although bird feeding is the most widespread form of intentional wildlife provisioning, we know relatively little about how the degree of anthropogenic feeding at a site impacts wild birds in ways relevant to disease transmission. We manipulated the density of bird feeders (low versus high) available at otherwise similar sites and tracked the local abundance, body condition (scaled-mass index), feeding behavior, and movement across the landscape in wild house finches (Haemorhous mexicanus), a feeder-dependent species subject to outbreaks of a contagious pathogen commonly spread at feeders. The local abundance of house finches was significantly higher at sites with high feeder density but, surprisingly, finches at high-density feeder sites had poorer body condition than those at low-density sites. Behaviorally, birds at high-density feeder sites had longer average feeding bouts and spent more time per day on feeders than birds at low-density feeder sites. Further, birds first recorded at low-density feeder sites were more likely to move to a neighboring high-density feeder site than vice versa. Overall, because local abundance and time spent on feeders have been linked with the risk of disease outbreaks in this species, effects of bird feeder density on both traits may, in turn, influence disease dynamics in house finches. Our results suggest that heterogeneity in the density of bird feeders can have diverse effects on wild birds, with potential consequences for disease transmission.
Master of Science
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Doxa, Aggeliki. "Complex population dynamics in a changing environment : the impact of density dependence and environmental factors on the vital rates and dynamics of two long-lived bird species." Paris, Muséum national d'histoire naturelle, 2009. http://www.theses.fr/2009MNHN0001.

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Un des principaux enjeux actuels en dynamique des populations est de fournir des outils adaptés pour prédire efficacement l’impact des changements globaux sur les espèces. Les interactions entre les populations et leur environnement peuvent être complexes, et leurs effets sur la variation des paramètres démographiques peuvent être décalés dans le temps. Les modèles de projection du risque d’extinction des populations ou de leur capacité à s’adapter à des modifications rapides des conditions environnementales nécessitent donc d’incorporer ce type de complexité dans leur structure pour qu’ils soient robustes. Cette thèse vise à identifier les aspects à prendre en compte dans l’analyse de l’impact des paramètres intrinsèques, comme la densité-dépendance, et des facteurs externes, comme le climat, sur les traits d’histoire de vie de l’espèce considérée et sur la dynamique des populations. Pour illustrer ces aspects, le Pélican frisé (Pelecanus crispus) et le Pélican blanc (Pelecanus onocrotalus) ont été choisis comme espèces modèles. D’après cette analyse, la densité-dépendance peut interagir avec les variations extrêmes de l’environnement, et influençer significativement le risque d’extinction. En outre, les variations temporelles de la densité et des facteurs climatiques peuvent influencer sur les patrons de survie, et générer de la synchronisation au sein et entre les populations. Enfin, les interactions entre espèces qui coopèrent durant la période de la reproduction et qui répondent différemment aux changements climatiques peuvent être cruciales pour la compréhension de ces changements sur les dynamiques de ces espèces
One of the challenges of modern population ecology is to provide the effective tools for population dynamics predictions in a rapidly changing environment. Reliable estimations of the effects of environmental variation on species dynamics require to integrate the effects of populations intrinsic parameters (e. G. , density) as well as external environmental factors. Importantly, these interacting effects are influenced by current and past conditions of the system, at both local and global scales. The present thesis aims to illustrate some of the aspects that need to be considered when assessing the impact of density and climatic factors on life history traits and on population dynamics, by using the example of two long-lived bird species, the Dalmatian pelican (Pelecanus crispus) and the Great white pelican (Pelecanus onocrotalus). The analyses showed that patterns of density-dependence can significantly interact with severe environmental stochasticity, producing unpredicted effects on population extinction risk. Large-scale climatic factors together with population density may similarly influence the survivorship of different population segments, resulting to spatial and temporal synchronisation between and within populations. Finally, interactions between until now cooperative species that are differently affected by climatic change may be a critical aspect for their future capacity to effectively respond to changing conditions
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Catlin, Daniel H. "Population Dynamics of Piping Plovers (Charadrius melodus) on the Missouri River." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/27442.

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Habitat loss and predation are threatening many shorebird populations worldwide. While habitat preservation often is preferable, sometimes habitat needs to be restored or created in order to stave off immediate declines. The Great Plains population of piping plovers (Charadrius melodus) was listed as threatened in 1986, and habitat loss and predation appear to be limiting the growth of this population. On the Missouri River, piping plovers nest on sandbars, but the damming of the mainstem of the Missouri in the mid-twentieth century reduced the natural capacity of the Missouri River to create sandbar habitat. In 2004, the United States Army Corps of Engineers (USACE) implemented a habitat creation project on the Gavins Point Reach of the Missouri River (stretch of river immediately downriver from the Gavins Point Dam) in an effort to promote recovery of piping plovers and the endangered least tern (Sternula antillarum). The USACE built 3 sandbars in 2004 â 2005 and built another sandbar on Lewis and Clark Lake in 2007. We studied the population dynamics of piping plovers in relationship to this newly engineered habitat. We monitored 623 nests on 16 sandbar complexes, to evaluate habitat selection, determine the factors affecting nesting success, and compare nesting success between natural and engineered habitat. From these 623 nests, we banded 357 adults and 685 chicks to investigate the factors affecting adult and juvenile survival. We used a logistic-exposure model to calculate nest survival. Adult and juvenile survival was calculated using Cormack-Jolly-Seber based models in Program MARK. We used the estimates from these studies to create a matrix population model for piping plovers nesting on the Gavins Point Reach. We used this model to predict the effects of engineered habitat on the population growth rate. Piping plovers selected for engineered sandbars and against natural and natural/modified habitats. Daily survival rate (DSR) on engineered habitats was significantly higher than on natural or natural modified habitats (log odds: 2.71, 95% CI: 1.20 â 6.08). Predator exclosures around nests did not affect DSR after controlling for the effects of date, nest age, and clutch size. Piping plover juvenile survival to recruitment was negatively related to nesting density on the relatively densely populated engineered sandbars. On the less dense natural sandbars, survival to recruitment was positively correlated with density. Adult survival did not appear to be related to density within our study. Movement within the study area was related also to density. Juveniles from densely populated engineered sandbars were more likely to leave engineered habitat to nest on natural sandbars than were juveniles hatched on less densely populated engineered sandbars. Movements among sandbars by breeding adults suggested that adults preferred engineered habitat. It is possible that juveniles moved to natural habitats because they were unable to compete with adults for the more desirable engineered habitats. Adults and juveniles emigrated from the study area at a higher rate after the 2006 breeding season, a year when water discharge was higher, nesting densities were higher, and reproductive success was lower (as a result of predation) than in the other years. Deterministic modeling suggested that engineered habitat significantly increased population growth. Decreased productivity over time and associated predicted negative population growth suggest that the amount of engineered habitat created was inadequate to sustain population growth, and/or that relatively high water discharge and nesting densities coupled with low reproductive rates and high emigration rates could lead to rapid declines in the plover population. Continued research is needed to determine the effects of these factors on long-term population growth. Our results suggest that habitat creation could be a viable short-term solution to population declines in shorebird populations limited by habitat loss, but high densities and increased predation associated with habitat creation indicate that other, long-term solutions may be required.
Ph. D.
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Books on the topic "Bird density"

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Watkins, Wedge W. Population density and habitat use by red-necked grebes on upper Klamath Lake, Klamath Co., Oregon. [Portland, Or.]: Oregon Dept. of Fish and Wildlife, Nongame Wildlife Program, 1988.

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Yamasaki, Mariko. Effects of clearcutting, patch cutting, and low-density shelterwoods on breeding birds and tree regeneration in New Hampshire northern hardwoods. Newtown Square, PA: United States Department of Agriculture, Forest Service, Northern Research Station, 2014.

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McCracken, Marti L. Factors affecting bird counts and their influence on density estimates. 1993.

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Rotella, Jay J. Analysis of calling frequency and density to evaluate a gray partridge population index. 1985.

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Ross, Andrew. Bird on Fire. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199828265.001.0001.

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Phoenix, Arizona is one of America's fastest growing metropolitan regions. It is also its least sustainable one, sprawling over a thousand square miles, with a population of four and a half million, minimal rainfall, scorching heat, and an insatiable appetite for unrestrained growth and unrestricted property rights. In Bird on Fire, eminent social and cultural analyst Andrew Ross focuses on the prospects for sustainability in Phoenix--a city in the bull's eye of global warming--and also the obstacles that stand in the way. Most authors writing on sustainable cities look at places like Portland, Seattle, and New York that have excellent public transit systems and relatively high density. But Ross contends that if we can't change the game in fast-growing, low-density cities like Phoenix, the whole movement has a major problem. Drawing on interviews with 200 influential residents--from state legislators, urban planners, developers, and green business advocates to civil rights champions, energy lobbyists, solar entrepreneurs, and community activists--Ross argues that if Phoenix is ever to become sustainable, it will occur more through political and social change than through technological fixes. Ross explains how Arizona's increasingly xenophobic immigration laws, science-denying legislature, and growth-at-all-costs business ethic have perpetuated social injustice and environmental degradation. But he also highlights the positive changes happening in Phoenix, in particular the Gila River Indian Community's successful struggle to win back its water rights, potentially shifting resources away from new housing developments to producing healthy local food for the people of the Phoenix Basin. Ross argues that this victory may serve as a new model for how green democracy can work, redressing the claims of those who have been aggrieved in a way that creates long-term benefits for all. Bird on Fire offers a compelling take on one of the pressing issues of our time--finding pathways to sustainability at a time when governments are dismally failing their responsibility to address climate change.
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West, Mason John, ed. At-sea distribution and abundance of seabirds off southern California: A 20-year comparison. Camarillo, CA: Cooper Ornithological Society, 2007.

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Feasibility of a random quadrat study design to estimate changes in density of Mexican spotted owls. Fort Collins, Colo: U.S. Dept. of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station, 1996.

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Scott, V. E. Breeding birds in uncut aspen and 6- to 10-year-old clearcuts in southwestern Colorado. 1988.

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Scott, V. E. Breeding birds and small mammals in pole-sized lodgepole pine and small inclusions of aspen in central Colorado. 1988.

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Book chapters on the topic "Bird density"

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George, T. Luke, and Lowell C. McEwen. "Relationships Between Bird Density, Vegetation Characteristics, and Grasshopper Density in Mixed-Grass Prairie of Western North Dakota." In Wildlife 2001: Populations, 465–75. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2868-1_35.

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Dhondt, André A., Erik Matthysen, Frank Adriaensen, and Marcel M. Lambrechts. "Population Dynamics and Regulation of a High Density Blue Tit Population." In Population Biology of Passerine Birds, 39–53. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75110-3_3.

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Smith, Susan M. "Winter Replacement Rates of High-Ranked Chickadees Vary with Floater Density." In Population Biology of Passerine Birds, 453–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75110-3_38.

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Lebreton, Jean-Dominique. "Modelling Density Dependence, Environmental Variability, and Demographic Stochasticity from Population Counts: An Example Using Wytham Wood Great Tits." In Population Biology of Passerine Birds, 89–102. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-75110-3_7.

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Nummi, P., H. Pöysä, J. Elmberg, and K. Sjöberg. "Habitat distribution of the mallard in relation to vegetation structure, food, and population density." In Aquatic Birds in the Trophic Web of Lakes, 247–52. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-1128-7_23.

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Ross, Andrew. "The Battle for Downtown." In Bird on Fire. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199828265.003.0009.

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Before the financial crash froze the motion of money, the plan to repopulate thinned-out downtowns had become an article of faith among advocates of low-carbon urbanism. Where else could the blueprint for truly sustainable living be realized? The technical difficulty and cost of retrofitting suburbs for higher density was prohibitive, even in the postwar inner-ring subdivisions that were more compact in their land use than today’s sprawl counterparts on the urban fringe. It was in city centers that the biggest improvements in energy efficiencies and emissions could be achieved, and, since the carbon clock was ticking, there was a consensus that their repopulation by middle-class residents ought to be accomplished posthaste. Urbanists, guided unerringly by Jane Jacobs’s prescriptions for vibrant street life, had long argued that the kind of society fostered by mixed-use and mixed-income downtown neighborhoods was more open-minded and mutually gratifying than the atomized lifestyle of the master-planned exurban community. After all, Jacobs’s version of the city had been driven primarily by concerns about quality of life, or what could be called cultural health. In her view, those who had planned the urban renewal projects of the 1950s and 1960s and hastened the population flight outwards had bequeathed a soulless, antiurban city—“a Great Blight of Dullness,” as she memorably put it. Hence, her full-throated praise for the daily festival of street life in mixed-use neighborhoods, even those condemned by the improvers as examples of urban blight. Compared to the presumed conformity of the suburbs, the humming, cosmopolitan milieu of her downtown sidewalks surely boasted a superior civilization. In the decades after Jacobs launched her downtown revolution, the argument for high-density core residence got a turbo boost from environmentalist quarters. Criticism of suburbia was no longer a matter of taste—how ugly and dull are these cookie-cutter houses and strip malls? Now it was backed up by estimates of the ecological costs of the unplanned, low-density tract development known as sprawl. In recent years, climate change had lent an extra sense of urgency to the case for downtown resettlement.
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Ross, Andrew. "Delivering the Good." In Bird on Fire. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199828265.003.0014.

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Why did I choose to end this book with the Gila River Indian Community’s effort to win back its water? Because it is a parable about how democracy and its courts can not only serve but also be served by the quest for sustainability. The GRIC water settlement brought a long struggle for environmental justice to a triumphant conclusion. Delivering justice meant that a large portion of the region’s available resources would be sequestered from the growth machine. Instead of supplying a new generation of low-density tract housing, the water could now be used to produce healthy, local food for the area population, and, if nonindustrial agriculture prevailed, the result would be a double win for carbon reduction. Surely, this is how a green polity ought to act, redressing the claims of those who have been aggrieved, and doing it in a way that extends long-term benefits for all. If all responses to environmental injustice were able to follow suit, it would be a welcome model for moving forward. Even if the Gila River example is unlikely to be replicated in other places, its guiding spirit is a sound one. What if the key to sustainability lies in innovating healthy pathways out of poverty for populations at risk, rather than marketing green gizmos to those who already have many options to choose from? These are not mutually exclusive options, of course, but the lessons I took away from my research convinced me of the pressing need for clear alternatives to the eco-apartheid syndrome that afflicts Phoenix and so many other cities. Building a low-carbon economy by targeting only the LOHAS demographic (Lifestyles of Health and Sustainability, the upmarket segment of 40 million, or 20 percent of consumers, nationally) will end up doing little more than adding a green gloss to patterns of chronic inequality. Likewise, placing all of our faith in clean-tech fixes will cede too much decision making to a closed circle of experts who, regardless of their technical prowess, will have no power to prevent the uneven application of their solutions.
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McKnight, Kevin P., Joseph P. Messina, Ashton M. Shortridge, Meghan D. Burns, and Bruce W. Pigozzi. "Using Volunteered Geographic Information to Assess the Spatial Distribution of West Nile Virus in Detroit, Michigan." In Geographic Information Systems, 1170–82. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-2038-4.ch070.

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West Nile Virus is a vector-borne flavivirus that affects mainly birds, horses, and humans. The disease emerged in the United States in 1999 and by 2001 had reached Michigan. In clinical human cases, the most common symptoms are fever, weakness, nausea, headache, and changes in mental state. The crow is the most common wildlife host in the life cycle of the virus. The state of Michigan, through the Michigan Department of Community Health, collected the spatial locations of over 8,000 dead birds (Corvidae), statewide, during 2002. The large number of samples made spatial and temporal hotspot detection possible. However, the volunteer reporting method produced a dataset with a direct correlation between the numbers and locations of the dead birds and human population density and accurately identifying hotspots remains a challenge. Geographic variation in dead bird intensity was modeled using both global and local spatial clustering algorithms. Statistical models identified overall spatial structure and local clustering. Identification of hotspots was confounded by limited information about the collection procedures, data availability and quality, and the limitations of each method.
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Bretagnolle, Vincent, and Julien Terraube. "Predator–prey interactions and climate change." In Effects of Climate Change on Birds, 199–220. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198824268.003.0015.

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Climate change is likely to impact all trophic levels, although the response of communities and ecosystems to it has only recently received considerable attention. Further, it is expected to affect the magnitude of species interactions themselves. In this chapter, we summarize why and how climate change could affect predator–prey interactions, then review the literature about its impact on predator–prey relationships in birds, and provide prospects for future studies. Expected effects on prey or predators may include changes in the following: distribution, phenology, population density, behaviour, morphology, or physiology. We review the currently available information concerning particular key topics: top-down versus bottom-up control, specialist versus generalist predators, functional versus numerical responses, trophic cascades and regime shifts, and lastly adaptation and selection. Finally, we focus our review on two well-studied bird examples: seabirds and raptors. Key future topics include long-term studies, modelling and experimental studies, evolutionary questions, and conservation issues.
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Sæther, Bernt-Erik, Steinar Engen, Marlène Gamelon, and Vidar Grøtan. "Predicting the effects of climate change on bird population dynamics." In Effects of Climate Change on Birds, 74–90. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198824268.003.0007.

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Climate variation strongly influences fluctuations in size of avian populations. In this chapter, we show that it is difficult to predict how the abundance of birds will respond to climate change. A major reason for this is that most available time series of fluctuations in population size are in a statistical sense short, thus often resulting in large uncertainties in parameter estimates. We therefore argue that reliable population predictions must be based on models that capture how climate change will affect vital rates as well as including other processes (e.g. density-dependences) known to affect the population dynamics of the species in question. Our survey of examples of such forecast studies show that reliable predictions necessarily contain a high level of uncertainty. A major reason for this is that avian population dynamics are strongly influenced by environmental stochasticity, which is for most species, irrespective of their life history, the most important driver of fluctuations in population size. Credible population predictions must therefore assess the effects of such uncertainties as well as biases in population estimates.
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Conference papers on the topic "Bird density"

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Nizampatnam, Lakshmi, and Walter Horn. "Investigation of Material Density Variations for Predicting Bird Impact Loads." In 49th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
16th AIAA/ASME/AHS Adaptive Structures Conference
10t. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2008. http://dx.doi.org/10.2514/6.2008-2252.

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Nizampatnam, Lakshmi S., and Walter J. Horn. "Investigation of Multi-Material Bird Models for Predicting Impact Loads." In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51005.

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This research work investigated the use of multi-material bird models for accurately predicting bird impact loads. Numerical simulations carried out using the SPH (Smoothed Particle Hydrodynamics) technique of LS-Dyna showed excellent correlation with the experimental results. The multi-material bird models of this work are more rigorous than in any previously published work, and include a realistic bird shape. Each material model was distinct, having its own density value (different from the other materials) and an associated equation of state. Results indicated that using a multi-material bird with various combinations of materials permits better correlation with experimental results.
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Maderankova, Denisa, and Ivo Provaznik. "Similarity/dissimilarity analysis of COI mitochondrial gene of chosen bird species based on nucleotide density." In 2010 10th IEEE International Conference on Information Technology and Applications in Biomedicine (ITAB 2010). IEEE, 2010. http://dx.doi.org/10.1109/itab.2010.5687604.

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JinLiang Wang and XiaoHua Wang. "Information extraction of building height and density based on quick bird image in Kunming, China." In 2009 Joint Urban Remote Sensing Event. IEEE, 2009. http://dx.doi.org/10.1109/urs.2009.5137614.

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Zhou, Qingdong, Penghui Zhu, Zhiming Huang, and Quanzhong Zhao. "Pest Bird Density Forecast of Transmission Lines by Random Forest Regression Model and Line Transect Method." In 2020 7th International Conference on Information, Cybernetics, and Computational Social Systems (ICCSS). IEEE, 2020. http://dx.doi.org/10.1109/iccss52145.2020.9336898.

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Asbury, Paul, Rachel Nichols, Greg Gadell, Mohamed Elsheikh, Brandon Galbraith, Brandon Horton, Josh Marino, et al. "Unsteady Flow Analysis Strategies for Flapping Flight." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-22102.

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A current project is underway to create a prototype of an anatomically correct seagull with biologically accurate flight kinematics. The presented work is focused on the computational fluid dynamics (CFD) analysis of bird flight kinematics. A finite volume approach, using Fluent, was used to attempt to model the kinematics of bird flight with varying degrees of freedom to analyze the lift, drag, pressure, and vortices magnitude associated with a range of flight kinematics. Dimensional analysis has been performed to analyze the effects of angle of incidence on the different sections of a seagull wing. Validated CFD analysis has been performed to identify optimal degree of freedom for generating maximum amount of lift while minimizing drag. The analysis benefitted from dynamic meshing and a user defined function to model the seagull wing, profiles of which were approximated by the S1223 airfoil. The user defined function allowed for variation of degrees of freedom to model the flight in the current bird prototype and to assess the effects of changing angles of incidence and inlet velocity on lift and drag. Difficulties were encountered when trying to accurately analyze unsteady aerodynamics over a flapping motion. The appropriate grid resolution, the user defined function, as well as the appropriate grid and dynamic mesh parameters within Fluent were all possible areas of concern. The grid resolution was determined by analyzing a steady state case and determining the variation in lift and drag values calculated by increasing the grid density. A user defined function was created that accurately represents the kinematics associated with the bird wing. A triangular grid was utilized for the dynamic mesh with re-meshing procedure activated at every iteration during the analysis. The final geometry provided an accurate method for dynamic re-meshing and overcame the problem of negative cell volume associated with re-meshing using a rectangular mesh configuration. It was determined that maximum cell volume, number of time steps, and time step interval were all important criteria when determining parameters for the unsteady flight analysis. Results indicate that the unsteady dynamics of bird flapping motion can be effectively represented with modified CFD analysis with updated finite volume scheme. Data indicates that values associated with varying angles of attack at a steady state cannot be used to model flapping flight. The paper will report on further validation to analyze the pressure, lift and drag associated with flapping flight in a three-dimensional study.
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Chen, Cheng-Hung, Ken W. Bosworth, and Marco P. Schoen. "Investigation of Particle Swarm Optimization Dynamics." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41343.

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In this work, a set of operators for a Particle Swarm (PS) based optimization algorithm is investigated for the purpose of finding optimal values for some of the classical benchmark problems. Particle swarm algorithms are implemented as mathematical operators inspired by the social behaviors of bird flocks and fish schools. In addition, particle swarm algorithms utilize a small number of relatively uncomplicated rules in response to complex behaviors, such that they are computationally inexpensive in terms of memory requirements and processing time. In particle swarm algorithms, particles in a continuous variable space are linked with neighbors, therefore the updated velocity means of particles influences the simulation results. The paper presents a statistical investigation on the velocity update rule for continuous variable PS algorithm. In particular, the probability density function influencing the particle velocity update is investigated along with the components used to construct the updated velocity vector of each particle within a flock. The simulation results of several numerical benchmark examples indicate that small amount of negative velocity is necessary to obtain good optimal values near global optimality.
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Pellegrini, Thomas. "Densely connected CNNs for bird audio detection." In 2017 25th European Signal Processing Conference (EUSIPCO). IEEE, 2017. http://dx.doi.org/10.23919/eusipco.2017.8081506.

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Qin, Zhiliang, Kui Cai, and Songhua Zhang. "Multiple parallel concatenation of low-density parity-check codes based on BIBD." In 2010 IEEE International Conference on Communication Systems (ICCS). IEEE, 2010. http://dx.doi.org/10.1109/iccs.2010.5685888.

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Liu, Tao, Weijing Zhang, Jie Ma, and Guanglei Zhang. "Adaptive Vibration Control of Towed Seismic Cable." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49304.

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The vibration of the towed seismic cable (streamer) is the main reason for the efficiency reduction of the seismic survey. In this paper, a vibration suppression scheme of the streamer in the seismic survey is investigated. The system model includes a hyperbolic partial differential equation with variable coefficient describing the seismic cable, and an ordinary differential equation describing the dynamic of the birds. Exact model knowledge and adaptive controllers, based on the Lyapunov method, are designed to suppress the vibration of streamer caused by the course deviations of the towing vessel and variations of streamer density. Under reasonable assumptions, the exact model knowledge and adaptive controllers exponentially and asymptotically drive the controlled span seismic cables displacement to zero, respectively. The proposed control laws not only suit for the depth control, but also the horizontal control.
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Reports on the topic "Bird density"

1

Yamasaki, Mariko, Christine A. Costello, and William B. Leak. Effects of clearcutting, patch cutting, and low-density shelterwoods on breeding birds and tree regeneration in New Hampshire northern hardwoods. Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern Research Station, 2014. http://dx.doi.org/10.2737/nrs-rp-26.

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Schutt, Timothy C., and Manoj K. Shukla. Computational Investigation on Interactions Between Some Munitions Compounds and Humic Substances. Engineer Research and Development Center (U.S.), February 2021. http://dx.doi.org/10.21079/11681/39703.

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Humic acid substances (HAs) in natural soil and sediment environments effect the retention and degradation of insensitive munitions compounds and legacy high explosives (MCs): DNAN, DNi- NH4+, nMNA, NQ, NTO (neutral and anionic forms), TNT, and RDX.A humic acid model compound has been considered using molecular dynamics, thermodynamic integration, and density functional theory to characterize the munition binding ability, ionization potential, and electron affinity compared to that in the water solution. Humic acids bind most compounds and act as both a sink and source for electrons. Ionization potentials suggest HAs are more susceptible to oxidation than the MCs studied. The electron affinity of HAs are very conformation-dependent and spans the same range as the munition compounds. When HAs and MCs are complexed the HAs tend to radicalize first thus buffering MCs against reductive as well as oxidative attacks.
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