Thesis (Ph. D.)--University of Wyoming, 2005. / Title from PDF title page (viewed on 10/26/2007). Includes bibliographical references.

Life history strategy suggests long lived bird species will adjust their nesting effort according to current conditions, balancing the costs of reproduction with their long-term needs for survival and future reproduction. The habitat conditions that produce these responses may differ between species, even within the same ecosystem, producing different nesting and population trends. I traced the pathway by which food availability influences the physiological condition of pre-breeding great egrets and white ibises through to reproductive measures, and the physiological condition of chicks. I focused on these two species with contrasting foraging strategies, in relation to foraging and habitat conditions to maximize the likelihood of application of these results to other wading bird species. Experimental food supplementation and physiology research on white ibis chicks demonstrated that in years with low prey availability white ibis were food limited, with increased levels of stress protein 60 and fecal corticosterone. This is the first study to demonstrate experimentally the response of stress protein 60 to changing levels of food availability. During a year with low prey availability (2007) white ibis adults and chick physiological condition was lower than that of great egrets. During the same year, fledging success was lower for both species (20% for white ibis versus 27% for great egret) but the magnitude of the decrease was particularly severe for the white ibis (76% decline versus 66% decline for the great egret). Results suggest white ibises modify their clutch size during years with poor habitat in accordance with life history traits of a long-lived species, whereas great egrets maintained their clutch size during years with poor habitat. / Increasing recession rates, hydrological reversals, and prey densities influenced white ibis, whereas great egrets were most influenced by prey densities and recession rates, with no effect of hydrological reversal. During the same year, fledging success was lower for both species (20% for white ibis versus 27% for great egret) but the magnitude of the decrease was particularly severe for the white ibis (76% decline versus 66% decline for the great egret). Results suggest white ibises modify their clutch size during years with poor habitat in accordance with life history traits of a long-lived species, whereas great egrets maintained their clutch size during years with poor habitat. Increasing recession rates, hydrological reversals, and prey densities influenced white ibis, whereas great egrets were most influenced by prey densities and recession rates, with no effect of hydrological reversals. This study is the first to make the link between landscape hydrology patterns, prey availability, and responses in wading bird nesting. These linkages provide critical insight into how species' nesting patterns could differ given the same time and spatial constraints and how that may be related to long-term nesting trends. This knowledge could ultimately lead to novel predictions about population and community patterns of wetland birds. / by Garth Herring. / Individual abstract for each chapter. / Thesis (Ph.D.)--Florida Atlantic University, 2008. / Includes bibliographical references at the end of each chapter. / Electronic reproduction. Boca Raton, FL : 2008 Mode of access: World Wide Web.

Food availability is the primary factor affecting the reproductive success in many species of birds. Diet composition can indicate diet quality, habitat use and niche requirements for breeding birds and may be variable across short and long-term time scales. Identifying primary prey types of nesting wading birds is important for the hydrologic restoration of wetlands. I collected nestling boluses during the 2008 and 2009 nesting seasons from three species of wading birds that nest in the northern Everglades: White Ibis, Tricolored Herons and Snowy Egrets. White Ibis bolus composition was dominated by crayfish in both years, but exhibited some variation with landscape water depth in 2009; fish use was greatest when the wetland landscape was relatively dry. In contrast, the prey of Tricolored Herons and Snowy Egrets were primarily fish and their respective diets did not differ from one another in either fish species composition or size structure. / by Robin A. Boyle. / Thesis (M.S.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.

Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Sept. 15, 2009). Thesis advisor: David A. Buehler. Vita. Includes bibliographical references.

Seasonal variation in food availability is one of the primary limitations to avian populations, particularly during the breeding season. However, the behavioral responses between species may differ based on foraging strategies. I examined the influence of food availability on landscape-level habitat selection, patch-level habitat selection, and movements of two wading bird species with divergent foraging strategies, the Great Egret and White Ibis. On a landscape scale, there appeared to be a relationship among resource availability, the temporal scale of the independent variable, and whether the response was similar or different between species. At the patch level, results demonstrated a relationship between resource availability and the spatial scale of the independent variables selected by birds. Species movements were consistent with the differing strategies. This study is the first to make the link between landscape hydrology patterns, prey availability, and responses in wading bird habitat selection at multiple spatial scales. / by James M. Beerens. / Thesis (M.S.)--Florida Atlantic University, 2008. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2008. Mode of access: World Wide Web.

城市發展被認為是導致本土物種滅絶的最主要原因，對鳥類群落結構有著極其重要的影響。雖然香港的城市化程度非常高，但對於鳥類尤其候鳥來說，其仍具有很高的保育價值。截至目前，有關城市化及多尺度生境因素對香港城市鳥類群落的影響的研究還非常少。 / 在城市景觀中，公園是鳥類多樣性的熱點地區。本研究選取了30個公園 (15個位於發達地區，15個位於新近發展地區) 作為研究樣地，分別於2010-2011年的繁殖季和越冬季，採用樣點法調查了所有樣地的鳥類群落。結果顯示，新近發展地區的鳥類群落較發達地區的更為均勻，嵌套程度更高。但不論何種發展類型，留鳥均為城市公園中的優勢群體。發達地區有較多的食穀鳥和偏好開闊生境的鳥類，而新近發展地區則吸引了較多的食蟲鳥、食蟲食果鳥和森林專一性鳥類。發達和新近發展地區的鳥類群落結構的差異，與生境均勻性 (400米尺度)、最大林地斑塊指數 (400米尺度) 及景觀聚集度指數 (400和1000米尺度) 密切相關。 / 香港公園的鳥類群落具有明顯的季節差異。繁殖季與越冬季的鳥種組成、鳥類豐富度和多樣性均有顯著差異。與繁殖季相比，越冬季的食蟲鳥、食蟲食果鳥及在灌木層和喬木層覓食的鳥類較繁殖季明顯增多，而食穀鳥及在地面覓食的鳥類則較繁殖季減少。 / 本研究進一步探討了公園屬性、人類干擾和植被結構對不同季節的鳥類群落結構的影響。結果顯示，公園面積和訪客率對於不同季節的鳥類群落有顯著影響。不論是繁殖季還是越冬季，鳥類豐富度和多樣性均隨公園面積的增加而增加；越冬季鳥類豐富度隨訪客率增加而減少。另外，繁殖季的鳥類總密度隨訪客率增加而增加。不同種團在不同季節對生境變量的反應也有所不同。例如，候鳥、食蟲鳥和食蟲食果鳥在越冬季隨公園面積的增加而增加，但隨訪客率的增加而減少；而雜食性鳥類在繁殖期均隨公園面積和訪客率的增加而增加。 / 對于不同景觀尺度的生境變量對冬季城市鳥類群落的影響的分析結果顯示，200米尺度上的林地和草地的覆蓋度對鳥類豐富度有顯著影響。單個物種的反應上，200和400米尺度上的斑塊密度對叉尾太陽鳥 (Aethopyga christinae) 的出現與消失有最好的解釋度。與叉尾太陽鳥不同，單一尺度生境變量對暗綠繡眼鳥 (Phylloscopus proregulus)、烏鶇 (Turdus merula)、灰背鶇 (T. hortulorum)、噪鵑 (Eudynamys scolopaceus) 和喜鵲 (Pica pica) 的分佈模式具有最好的解釋度，即200或400米尺度上的植被（包括林地、灌木和草地）覆蓋度對其在特定樣地的出現與消失有顯著影響。總之，小尺度生境變量 (400米以內) 對香港城市鳥類群落的影響值得更多關注。 / 最後，本文還探究了景觀 (400米) 和斑塊尺度上的生境變量對冬季鳥類群落的共同影響。非度量多維標度 (Non-metric Multi-Dimensional Scaling) 分析結果顯示，景觀尺度上的林地比例和斑塊密度及斑塊尺度上的樹木密度對鳥類分佈有強烈影響。多尺度交叉模型對候鳥、食穀鳥、食蟲鳥和食蟲食果鳥的分佈均有很好的解釋度。另外，相對于單一的景觀或斑塊尺度模型，多尺度交叉模型也能更好地解釋單個物種的分佈模式。可以說，景觀變量的加入能大大提高單一的斑塊尺度模型的預測能力。綜上，同時考慮景觀和斑塊尺度上生境變量對鳥類群落的共同影響是非常必要的。 / 本研究首次系統地研究了香港城市公園的鳥類群落結構及多尺度生境變數對鳥類分佈的影響；研究結果能為土地擁有者和公園管理者更好的保育城市生態系統提供理論依據。 / Urban development affects avian community structure dramatically, and it is considered a major cause of native species extinction. Hong Kong is a highly urbanized city, but has great conservation values for birds particularly migrants. There is a paucity of information on the effects of urbanization and multi-scale habitat characteristics on urban birds in Hong Kong. / Parks are hotspots of avian diversity in urban landscapes. Thirty parks, scattered throughout the territory, were selected as sampling sites from developed and new growth areas. Bird community structure was studied in the breeding and wintering seasons in 2010-2011. Regarding the effects of urbanization, bird communities in the new growth areas were more homogeneous and nested than those in the developed areas. Residents dominated urban parks in both development types. More granivores and open-habitat species, but fewer insectivores, insectivore-frugivores, and forest-specialist birds appeared in the developed areas than in the new growth areas. These differences were strongly associated with habitat evenness and largest patch index for woodland at 400-m scale and contagion index at 400- and 1000-m scales. / There were obvious seasonal differences in urban bird communities. Species composition, richness, and diversity were significantly different between the breeding and wintering seasons. Compared to breeding bird communities, more insectivores, insectivore-frugivores, and species feeding on plants, but less granivores and species feeding on the ground appeared in the wintering season. / The effects of park attributes, human disturbance, and vegetation structure on the seasonal differences were determined. Species richness and diversity were positively affected by park size in both seasons. Species richness was negatively affected by visitor rate in the wintering season. Total bird density increased with visitor rate, but only in the breeding season. In other words, park size and visitor rate were the major factors affecting bird communities in both seasons. Moreover, different species groups had different responses to habitat characteristics in different seasons. For examples, migrants, insectivores, and insectivore-frugivores were positively affected by park size, but negatively by visitor rate in the wintering season. However, omnivores in the breeding season increased with both park size and visitor rate. / The effects of habitat characteristics at five landscape scales on wintering bird communities were addressed. Total species richness was significantly affected by the availability of woodland and grassland at 200-m scale. For the six selected species, the incidence of Fork-tailed Sunbird (Aethopyga christinae) was affected by patch density, positively at 200-m scale but negatively at 400-m scale, and the incidences of the other five species (including Pallas's Leaf Warbler Phylloscopus proregulus, Common Blackbird Turdus merula, Grey-backed Thrush T. hortulorum, Asian Koel Eudynamys scolopaceus, and Eurasian Magpie Pica pica) were best predicted by the availability of greenspaces within 400 m. Consequently, factors at fine scales (within 400 m) should be more concerned while conserving birds in Hong Kong. / Finally, the cross-scale effects of habitat measurements at 400-m landscape and local scale on wintering bird communities were examined. The percentage of woodland and patch density at landscape scale, and tree density at local scale were mostly strongly correlated with species distribution. Most species groups and the incidences of individual species were better predicted by cross-scale approaches, and landscape characteristics increased the efficiency of local-only models. It is necessary to simultaneously consider the joint effects of landscape- and local-scale characteristics on birds in urban environments. / This research is the first to systematically study bird communities in urban parks of Hong Kong, and determine the factors influencing bird distribution patterns at multiple scales. The knowledge acquired would help land owners and park managers to conserve a more diverse ecosystem in Hong Kong. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhou, Daqing. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 144-165). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.I / Acknowledgements --- p.VI / Table of Contents --- p.VIII / List of Tables --- p.XIII / List of Figures --- p.XVI / List of Appendices --- p.XVIII / Chapter CHAPTER 1 --- Background --- p.1 / Chapter 1.1 --- Bird community ecology and its developments --- p.1 / Chapter 1.2 --- Effects of urbanization on urban bird communities --- p.2 / Chapter 1.2.1 --- Urbanization --- p.2 / Chapter 1.2.2 --- Major impacts of urbanization --- p.5 / Chapter 1.3 --- Effects of multi-scale habitat characteristics on bird communities --- p.7 / Chapter 1.3.1 --- Importance of spatial scale --- p.7 / Chapter 1.3.2 --- Effects of local-scale habitat characteristics on urban bird community --- p.9 / Chapter 1.3.2.1 --- Park attributes --- p.9 / Chapter 1.3.2.2 --- Human disturbance --- p.11 / Chapter 1.3.2.3 --- Vegetation configuration --- p.12 / Chapter 1.3.3 --- Effects of landscape-scale habitat characteristics on urban bird community --- p.13 / Chapter 1.3.3.1 --- Various landscape-scale habitat characteristics --- p.14 / Chapter 1.3.3.2 --- Scalar effects of landscape-scale habitat characteristics --- p.16 / Chapter 1.3.3.3 --- Combined effects of local- and landscape-scale habitat characteristics --- p.17 / Chapter 1.4 --- Overview of Hong Kong --- p.18 / Chapter 1.4.1 --- General situation --- p.18 / Chapter 1.4.2 --- Knowledge gaps --- p.20 / Chapter 1.4.3 --- Research significances --- p.21 / Chapter CHAPTER 2 --- Avian community structure of urban parks in developed and new growth areas: A landscape-scale study in Southeast Asia --- p.22 / Chapter 2.1 --- Introduction --- p.22 / Chapter 2.2 --- Methods --- p.26 / Chapter 2.2.1 --- Study area --- p.26 / Chapter 2.2.2 --- Bird census --- p.27 / Chapter 2.2.3 --- Landscape-level habitat factors at 400- and 1000-m scales --- p.36 / Chapter 2.2.4 --- Data analyses --- p.38 / Chapter 2.2.4.1 --- Community attributes --- p.38 / Chapter 2.2.4.2 --- Species groups --- p.39 / Chapter 2.2.4.3 --- Species composition --- p.39 / Chapter 2.2.4.4 --- Nestedness --- p.41 / Chapter 2.2.4.5 --- Community responses to landscape-scale habitat factors --- p.41 / Chapter 2.3 --- Results --- p.42 / Chapter 2.3.1 --- Comparisons of community attributes between developed and new growth areas --- p.43 / Chapter 2.3.2 --- Responses of species groups to the development type --- p.45 / Chapter 2.3.3 --- Differences in species composition --- p.46 / Chapter 2.3.4 --- Nestedness of developed and new growth areas --- p.49 / Chapter 2.3.5 --- Responses of bird community to landscape-scale habitat factors --- p.49 / Chapter 2.4 --- Discussion --- p.50 / Chapter 2.4.1 --- Bird community structure for the two development types --- p.50 / Chapter 2.4.2 --- Responses to landscape-scale habitat factors at two spatial scales --- p.56 / Chapter CHAPTER 3 --- Seasonal dynamics of bird community structure in urban parks of Hong Kong --- p.58 / Chapter 3.1 --- Introduction --- p.58 / Chapter 3.2 --- Methods --- p.59 / Chapter 3.2.1 --- Study area --- p.59 / Chapter 3.2.2 --- Bird census --- p.60 / Chapter 3.2.3 --- Data analyses --- p.62 / Chapter 3.3 --- Results --- p.64 / Chapter 3.3.1 --- Differences in community attributes --- p.66 / Chapter 3.3.2 --- Differences in the composition of species groups --- p.67 / Chapter 3.3.3 --- Differences in individual species composition --- p.68 / Chapter 3.3.4 --- Nestedness pattern of breeding and wintering bird communities --- p.69 / Chapter 3.4 --- Discussion --- p.69 / Chapter 3.5 --- Conclusions --- p.73 / Chapter CHAPTER 4 --- How would size, age, human disturbance, and vegetation structure affect bird communities of urban parks in different seasons? --- p.74 / Chapter 4.1 --- Introduction --- p.74 / Chapter 4.2 --- Methods --- p.76 / Chapter 4.2.1 --- Study area --- p.76 / Chapter 4.2.2 --- Bird census --- p.78 / Chapter 4.2.3 --- Measurements of human disturbance --- p.78 / Chapter 4.2.4 --- Vegetation structure --- p.79 / Chapter 4.2.5 --- Data analyses --- p.80 / Chapter 4.3 --- Results --- p.82 / Chapter 4.3.1 --- Species number --- p.83 / Chapter 4.3.2 --- Species diversity --- p.85 / Chapter 4.3.3 --- Total bird density --- p.86 / Chapter 4.3.4 --- Responses of seasonal status classes and feeding guilds --- p.86 / Chapter 4.4 --- Discussion --- p.89 / Chapter 4.5 --- Conclusions --- p.93 / Chapter CHAPTER 5 --- How did spatial scale affect the responses of wintering bird communities in urban parks? The importance of small landscape-scale approaches --- p.95 / Chapter 5.1 --- Introduction --- p.95 / Chapter 5.2 --- Methods --- p.97 / Chapter 5.2.1 --- Study area --- p.97 / Chapter 5.2.2 --- Bird census --- p.98 / Chapter 5.2.3 --- Habitat characteristics at five landscape scales --- p.99 / Chapter 5.2.4 --- Data analyses --- p.102 / Chapter 5.3 --- Results --- p.103 / Chapter 5.3.1 --- Species selected in this study --- p.103 / Chapter 5.3.2 --- Responses of total species richness to five landscape-scale habitat characteristics --- p.105 / Chapter 5.3.3 --- Responses of six specific species to five landscape-scale habitat characteristics --- p.106 / Chapter 5.4 --- Discussion --- p.109 / Chapter 5.4.1 --- Most influential spatial scales --- p.109 / Chapter 5.4.2 --- Effects of habitat availability and patch distribution at varying scales --- p.111 / Chapter 5.5 --- Conclusions --- p.113 / Chapter CHAPTER 6 --- Cross-Scale effects of landscape- and local-scale habitat characteristics on wintering bird communities in highly urbanized Hong Kong --- p.115 / Chapter 6.1 --- Introduction --- p.115 / Chapter 6.2 --- Methods --- p.117 / Chapter 6.2.1 --- Study area --- p.117 / Chapter 6.2.2 --- Bird census --- p.119 / Chapter 6.2.3 --- Landscape-scale habitat characteristics --- p.119 / Chapter 6.2.4 --- Local-scale habitat characteristics --- p.121 / Chapter 6.2.5 --- Data analyses --- p.122 / Chapter 6.2.5.1 --- Correlation analyses --- p.122 / Chapter 6.2.5.2 --- Cross-scale effects of landscape- and local-scale characteristics on bird communities --- p.123 / Chapter 6.2.5.3 --- Cross-scale effects of landscape- and local-scale characteristics on species groups --- p.125 / Chapter 6.2.5.4 --- Comparison between single-scale and cross-scale approaches for some specific species --- p.125 / Chapter 6.3 --- Results --- p.126 / Chapter 6.3.1 --- Community responses to landscape- and local-scale habitat characteristics --- p.126 / Chapter 6.3.2 --- Responses of species groups --- p.128 / Chapter 6.3.3 --- Responses of six individual species --- p.130 / Chapter 6.4 --- Discussion --- p.131 / Chapter 6.4.1 --- Responses of community and species groups to landscape- and local-scale habitat characteristics --- p.131 / Chapter 6.4.2 --- Landscape- versus local-scale habitat characteristics --- p.135 / Chapter 6.5 --- Conclusions --- p.136 / Chapter CHAPTER 7 --- General conclusions --- p.138 / Chapter 7.1 --- Major results and recommendations --- p.138 / Chapter 7.2 --- Further investigations --- p.142 / References --- p.144 / Appendices --- p.166 / Publications --- p.188

Severe declines in the number of some songbirds over the last 40 years have caused heated debate amongst interested parties. Many factors have been suggested as possible causes for these declines, including an increase in the abundance and distribution of an avian predator, the Eurasian sparrowhawk Accipiter nisus. To test for evidence for a predator effect on the abundance of its prey, we analyse data on 10 species visiting garden bird feeding stations monitored by the British Trust for Ornithology in relation to the abundance of sparrowhawks. We apply Bayesian hierarchical models to data relating to averaged maximum weekly counts from a garden bird monitoring survey. These data are essentially continuous, bounded below by zero, but for many species show a marked spike at zero that many standard distributions would not be able to account for. We use the Tweedie distributions, which for certain areas of parameter space relate to continuous nonnegative distributions with a discrete probability mass at zero, and are hence able to deal with the shape of the empirical distributions of the data. The methods developed in this thesis begin by modelling single prey species independently with an avian predator as a covariate, using MCMC methods to explore parameter and model spaces. This model is then extended to a multiple-prey species model, testing for interactions between species as well as synchrony in their response to environmental factors and unobserved variation. Finally we use a relatively new methodological framework, namely the SPDE approach in the INLA framework, to fit a multi-species spatio-temporal model to the ecological data. The results from the analyses are consistent with the hypothesis that sparrowhawks are suppressing the numbers of some species of birds visiting garden feeding stations. Only the species most susceptible to sparrowhawk predation seem to be affected.

To underpin and improve advice given to government and other interested parties on the state of Britain’s common songbird populations, new models for analysing ecological data are developed in this thesis. These models use data from the British Trust for Ornithology’s Constant Effort Sites (CES) scheme, an annual bird-ringing programme in which catch effort is standardised. Data from the CES scheme are routinely used to index abundance and productivity, and to a lesser extent estimate adult survival rates. However, two features of the CES data that complicate analysis were previously inadequately addressed, namely the presence in the catch of “transient” birds not associated with the local population, and the sporadic failure in the constancy of effort assumption arising from the absence of within-year catch data. The current methodology is extended, with efficient Bayesian models developed for each of these demographic parameters that account for both of these data nuances, and from which reliable and usefully precise estimates are obtained. Of increasing interest is the relationship between abundance and the underlying vital rates, an understanding of which facilitates effective conservation. CES data are particularly amenable to an integrated approach to population modelling, providing a combination of demographic information from a single source. Such an integrated approach is developed here, employing Bayesian methodology and a simple population model to unite abundance, productivity and survival within a consistent framework. Independent data from ring-recoveries provide additional information on adult and juvenile survival rates. Specific advantages of this new integrated approach are identified, among which is the ability to determine juvenile survival accurately, disentangle the probabilities of survival and permanent emigration, and to obtain estimates of total seasonal productivity. The methodologies developed in this thesis are applied to CES data from Sedge Warbler, Acrocephalus schoenobaenus, and Reed Warbler, A. scirpaceus.

A thorough understanding of demographic parameters and their contribution to overall population growth is fundamental to effective conservation of small populations, but this information is often lacking. The Pacific Coast population of the Western Snowy Plover (Charadrius nivosus nivosus) is listed as threatened and has been the target of long-term, multi-pronged management in Oregon. The Oregon coastal population has been intensively monitored since 1990, and over 80% of the population is color banded, but a comprehensive analysis of demographic parameters and the effect of management on vital rates and population growth has been unavailable until now. Here, the author used capture-mark-resight techniques to document survival at each life stage and to explore environmental and management factors that best explained variation in survival over a 25-year study period. The author analyzed the effects of habitat restoration, exclosure use, and lethal predator management on survival at appropriate life stages and evaluated the effects of one management option, lethal predator control, on overall population growth. Chick survival to fledging improved dramatically after the chicks' 5th day, was higher in years with lethal predator management, and was highest during the peak of the long brood-rearing season. Cold weather, particularly during the chicks' first 5 days, had a negative effect on survival to fledging. Juvenile survival from fledging to the following spring declined over the study period, but rebounded after implementation of lethal predator management. Adult survival was lower in wetter-than-average winters and higher in years with predator management. The author used the survival analyses and productivity data collected over 25 years in a matrix population model to reveal that population growth is most sensitive to changes in adult survival, and that while predator management is important for continued growth, its use may be scaled back by as much as 50% and still maintain a growing population. My results, encompassing all phases of this species' life cycle, demonstrate that with holistic and thoughtful adaptive management, and with the cooperation of numerous agencies, a balance can be struck between protection and control of native species to bring about recovery of species threatened with (local) extinction.

There are hundreds of thousands of fisheries-related mortalities of seabirds each year. Population trends for these species are highly influenced by changes in adult survival, their maximum growth rates are low, and little additional mortality can have a large impact on the population. As a result, many albatrosses and petrels are at risk of extinction, but limited demographic data makes it difficult to quantify the risk for many species. The goal of this research is to use population modelling tools to assess potential impacts with minimal data. In particular, the question of how much additional mortality a population can sustain is addressed when there is only knowledge of the adult survival rate, age at first breeding, and the number of breeding pairs. In this thesis, a simple decision rule designed for marine mammals is applied to albatrosses and petrels. In order to use this rule, adult survival, age at first breeding, a minimum estimate of the population size, and the maximum growth rate of the population are needed. While estimation of adult survival is well developed, work was required to calculate the other values from available data. A simple population model was developed to extrapolate from the number of breeding pairs to the total population size (given survival and age at first breeding); the effect of variable fecundity rates on the calculation of generation time and the maximum growth rate of a population was examined, relative to an estimate that only requires survival and age at first breeding; and a method for estimating the age at first breeding using capture-recapture data was suggested that accounts for study duration and emigration, in addition to capture probability. This work can help managers make better informed decisions when little is known about a population. For example, around 5,800 pairs of Gibson's albatrosses (Diomedea gibsoni) breed each year. Based on the work presented in this thesis, they may be able to sustain 1,000 - 1,200 additional mortalities per year. However, given concern about their conservation status, a mortality level below 100 - 120 is desired, and any mortality beyond that level suggests a need for more intensive management.