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Lapoint, Richard, and Noah Whiteman. "How a bird is an island." BioMed Central, 2012. http://hdl.handle.net/10150/610298.
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Replicate adaptive radiations occur when lineages repeatedly radiate and fill new but similar niches and converge phenotypically. While this is commonly seen in traditional island systems, it may also be present in host-parasite relationships, where hosts serve as islands. In a recent article in BMC Biology, Johnson and colleagues have produced the most extensive phylogeny of the avian lice (Ischnocera) to date, and find evidence for this pattern. This study opens the door to exploring adaptive radiations from a novel host-parasite perspective.See research article: http://www.biomedcentral.com/1741-7007/10/52 webcite
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Rosenfeld, Kristen Marie. "Ecology of Bird Island, North Carolina: an uninhabited, undeveloped barrier island." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-07122004-185722/.
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Barrier islands include some of the most endangered and fragmented ecosystems on the Atlantic coast, providing critical habitat for many species, including some that are threatened and endangered. As the vast majority of these islands have been developed for human usage study and protection of the few remaining undeveloped and undisturbed islands is critical. This study was undertaken in order to characterize the vascular plant communities on Bird Island, an uninhabited, undeveloped barrier island on the border of North and South Carolina, with the objectives of a thorough survey of flora, vegetation, and environment, classification of plant communities, and multivariate analysis of vegetation and environmental data. A floristic inventory of the island and its associated marshes was conducted during the growing season (May-November) of 2002 and 2003. One hundred four 100m2 plots were inventoried for vegetation and environment using protocols developed by the Carolina Vegetation Survey. Plant communities were identified according to the National Vegetation Classification, the Classification of the Natural Communities of North Carolina, and the Carolina Vegetation Survey. Interpretation of vegetation patterns was based on multivariate analysis of vegetation and environmental data. Ninety-one vascular plant species in 35 families, including 4 exotic species, were distributed across 12 communities. Communities on Bird Island appear to be distinctive when compared to those described for other barrier islands in the region. Additionally, the vegetation survey on Bird Island revealed suitable habitat for the federally listed Seabeach amaranth (Amaranthus pumilus); an important dune-building annual of the North American Atlantic coast. Surveys of the late 1980s and early 1990s documented small populations of Seabeach amaranth on Bird Island, but our work found no indication of a population in either 2002 or 2003. Seabeach amaranth?s existence range-wide is threatened by habitat loss and fragmentation, herbivory, and anthropogenic disturbances such as beach driving, hardening, and raking. Published work on this species has been limited, but observations of natural, experimental, and restored populations have indicated relationships between distance from the ocean and both survivorship and reproduction. To quantify this relationship, 314 plants were transplanted at varying distances from the ocean. Plants were monitored monthly from June until December 2003. We found that distance from the ocean had a significant effect on survivorship, size, and reproduction; however, presence of webworms and ghost crabs did not have significant effects on size or reproduction. Distance from the ocean combined with complex factors such as over wash and soil salinity appear to be important indicators of success for both natural and restored populations of this species, and landscape position should be incorporated into future conservation and restoration efforts for A. pumilus in the Carolinas and elsewhere. Overall, we found that the vegetation of Bird Island is mostly intact, with few exotic, invasive species present. Bird Island?s protected status and limited presence of invasive species make it suitable habitat for continued protection and further restoration of rare, threatened, or endangered species, such as Seabeach amaranth. Atlantic barrier islands in general provide distinct community types combined with a small species pool, a combination that may provide a model for examination of larger ecological questions.
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Rosenfeld, Kristen Marie Wentworth Thomas R. Suiter Dale William. "Ecology of Bird Island, North Carolina an uninhabited, undeveloped barrier island /." Connect to this title online, 2004. http://www.lib.ncsu.edu/theses/available/etd-07122004-185722/.
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Johnson, Kate Marie. "Species colonization and extinction processes in an island bird community." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54729.
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Species invasion and range shifts are widely reported and facilitate novel interactions among potential competitors in plant and animal communities worldwide. However, predicting which novel interactions will result in the extirpation of subordinate competitors is challenging. Coexistence versus extinction as alternative outcomes of competition between resident and colonizing species may arise due to (1) variation in interaction strength, (2) change in other demographic drivers more influential than those linked to competition, or (3) differences in the extent to which resources are equitably partitioned between competitors, which may in turn depend on the spatial scale examined. To date, however, empirical studies suggest these factors rarely align to cause the competitive exclusion of native species. I used a combination of field experiments and demographic analyses to test the hypothesis that colonizing fox sparrows (Passerella iliaca) have caused the 0.6% per year decline of a song sparrow (Melospiza melodia) population resident on Mandarte Island, BC, Canada. Several lines of evidence indicate that interspecific competition for winter food has: a) reduced survival in juvenile song sparrows after colonization by fox sparrows in 1975, b) led to an inverse relationship between juvenile song sparrow survival and fox sparrow population size, c) excluded song sparrows from high-quality foraging sites in winter via consistent behavioural dominance by fox sparrows and complete overlap of fox and song sparrow preference for local seeds, despite d) no evidence of competition for breeding territories or nesting habitat. My results suggest that in the absence of rapid ecological or evolutionary shifts in niche dimension, song sparrows will likely be extirpated from Mandarte Is., thus demonstrating that competitive exclusion of native species can occur when interactions are strong and resources are not easily partitioned.Forestry, Faculty of
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Arenas, Patricia Brekke. "Conservation genetics of an Island endemic bird, The Hihi (Notiomystis Cincta)." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504901.
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Soria, Carvajal Monica Cecilia. "Avian seed dispersers of the invasive Rubus niveus (Rosaceae) in Santa Cruz Island, Galapagos, Ecuador." Diss., St. Louis, Mo. : University of Missouri--St. Louis, 2006. http://etd.umsl.edu/r1761.
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Green, David Bruce. "Foraging ecology of Cape Gannets (Morus Capensis) at Bird Island, Algoa Bay." Thesis, Nelson Mandela Metropolitan University, 2013. http://hdl.handle.net/10948/d1020790.
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The Cape gannet has undergone considerable population change and redistribution over the past 50 years. This has been linked to shifts in the abundance and distribution of their dominant prey, sardine and anchovy. Five breeding colonies, along the west coast of Southern Africa, have shown rapid population declines as a result of reduced prey availability. In contrast, a single colony (Bird Island, Algoa Bay) on the south coast of South Africa has, over the same period, grown fivefold and now supports approximately two thirds of the total population. Due to its conservation importance, and isolation from other breeding localities, it is important to assess the health of the Bird Island colony, and determine how foraging distribution relates to the environment to evaluate current measures of protection. This was achieved through two related studies; a long-term dietary analysis spanning 34 years, and a spatial foraging study, which related three years of tracking data to estimates of prey availability, oceanographic features and marine protected areas (MPAs). The results of the dietary study showed that the dietary constituents of Cape gannets breeding at Bird Island have remained similar over the last three decades, but the importance of sardine and anchovy has increased significantly. For sardine, in particular, this reflects an increased availability of this species (as deduced from hydroacoustic surveys) within the foraging range of the Bird Island colony. The dietary abundance of anchovy was found to be negatively correlated with that of sardine. Surprisingly,.the dietary abundance of anchovy was also negatively correlated with estimates of its availability based on acoustic surveys. The latter is likely to be due to sardine being a preferred prey item. Recent decreases in the dietary contribution of sardine (since 2005) suggest that this species is becoming less available to gannets, with profound implications in terms of nutrient gain associated with foraging. However, this has been mediated by an increase in the dietary contribution of anchovy, which now accounts for the vast majority of prey taken. Spatially, the foraging range of the Bird Island colony expanded during the three years of study, indicating an increase in effort. This increase was likely in an effort to track a distributional change of sardine and anchovy, which showed an apparent westward shift during the study period. There was, however, no evidence of birds tracking features associated with high productivity. This may have been partly due to anomalously warm conditions during the summer of 2012/2013, in which an absence of coastal upwelling prevented surface cooling. Nonetheless, low sea surface temperatures and high chlorophyll a concentrations do not seem to be reliable indicators of important Cape gannet foragingareas. Foraging effort was largely concentrated outside of MPAs, indicating that the current MPA network provides little protection for foraging gannets. This could change with the additional protection of the proposed Greater Addo Elephant National Park MPA expansion, as prey species are allowed to recover following the removal of fishing pressure. Overall, the colony appears to be in good condition as the diet is still dominated by live prey items, and the foraging range remains smaller than many of the colonies along the west coast. However, it is important that monitoring be continued, in particular with respect to changes in the availability of sardine and anchovy. Long-term shifts of these species out of the colony‘s foraging range could negatively influence the population in the future. This might be worsened by interspecific competition for prey resources. Considering the conservation importance of this population, maintenance of healthy prey stocks within the home range of breeding Cape gannets should be prioritised in order to prevent declines similar to those observed at west coast colonies.
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Stevenson, Claire. "Ecological impacts of Australian Ravens on bush bird communities on Rottnest Island." Thesis, Stevenson, Claire (2011) Ecological impacts of Australian Ravens on bush bird communities on Rottnest Island. Honours thesis, Murdoch University, 2011. https://researchrepository.murdoch.edu.au/id/eprint/7492/.
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The Australian Raven Corvus coronoides is a predator of the eggs and nestlings of bush birds on Rottnest Island, Western Australia. Nest predation is a threatening process of island birds, and when combined with other threatening processes, such as habitat fragmentation and degradation, sustained nest predation can cause declines in bush bird communities. The terrestrial habitats on Rottnest Island have been historically fragmented through land clearing, so concern was raised by the Rottnest Island Authority regarding the impact of the Australian Raven on bush bird communities. The aims of this study were to describe the ecology of the Australian Raven on Rottnest Island, in particular the feeding ecology, and to evaluate how important bush birds are in the diet of the Australian Raven.
To determine the rate of nest predation by the Australian Raven, an artificial nest experiment was conducted over four months from August to November, over six study sites. The diet of the Australian Raven was analysed by laboratory examination of raven stomach samples. In addition, observational data collected at the study sites during the study period was used to quantify the behaviour, abundance and distribution of ravens, and compared to bush bird distribution on Rottnest Island.
During this study, ravens predated 20% of the artificial nests, indicating a high capacity for potential population impacts. Nest predation was confirmed by the presence of birds in the stomach contents of ravens from Rottnest, but plant material and invertebrates were found to be more important in the diet. The Australian Raven prefers the disturbed and urban habitat areas of Rottnest Island for feeding, roosting and breeding. Bush birds avoid these areas, and prefer remnant and revegetated areas.
The results of this study have identified the Australian Raven as a potential predator of nesting bush birds on Rottnest Island. However, restoration of island vegetation may be having a positive effect on bush bird communities that outweighs losses of eggs and nestlings to ravens. In view of these results, continued management of the raven population is recommended as a precautionary approach so that the impacts of nest predation on bush birds are limited. Meanwhile, the population dynamics of selected bush birds can be assessed to confirm that they are recovering in response to habitat restoration programs.
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Rousseau, Josée. "Avian diversity, assemblages and use of vegetation, mainly by shrub-nesters, in an urban ecosystem." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82419.
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Urbanization is known to have a negative impact on biodiversity. However, it is possible to increase bird species richness in cities through local actions such as increasing vegetation density and diversity. My first objective was to compare bird density and diversity on the island of Montreal among four urban habitat types: low-density and medium-density residential sectors, and residential and natural parks. A second objective was to determine the presence of bird species assemblages within these four urban habitats and a third was to explore associative relationships among six mainly shrub-nesting bird species and the vegetation they use. Point counts were conducted in each of 103 locations. Environmental variables measured consisted of the type (coniferous versus deciduous), density and height of vegetation within each 1 ha sector. Results revealed a decrease in bird abundance from medium-density residential habitats, residential park, low density residential habitats to natural parks and an increase in diversity from medium density residential habitats, low density residential habitats, residential parks to natural parks. Bird assemblages were determined through correspondence analysis. Most bird species were associated with at least one type of urban habitat. Associations between bird species and vegetation were measured through canonical correspondence analysis. The six focal species associated with shrubs demonstrated different levels of association with different habitat variables.
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Rishworth, Gavin Midgley. "Time-activity budgets of cape gannets (Morus Capensis) at Bird Island, Algoa Bay." Thesis, Nelson Mandela Metropolitan University, 2014. http://hdl.handle.net/10948/d1021046.
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For several decades now, seabirds have been considered to be useful indicators of the state of their prey resources because of how they reflect lower-level trophic variability through proxies such as diet or behaviour. However, collection of appropriate data is often challenging in the marine environment because of logistical or financial constraints. In this study, time-activity budgets were studied in the Cape gannet (Morus capensis), a seabird which has been advocated as a potential bioindicator for local epipelagic prey. VHF transmitters attached to PVC leg-rings were fitted to 50 adult breeding pairs during the 2011/2012 and 2012/2013 breeding seasons at Bird Island, Algoa Bay, to determine whether an automated method of continuously collecting time-activity budget data can replace conventional laborious direct observations. To validate that the foraging trip duration data generated from the automated method was a reflection of foraging effort, Time-Depth Recorders (TDRs) were simultaneously equipped to birds with VHF transmitters for three weeks. In order to assess the influence of factors other than prey availability on parent time-activity budgets, sex, chick age and body condition were measured. Additionally, chick growth and survival were recorded in order to investigate the gender-specific effects of parental time-activity budget variability on these parameters. Attachment of VHF transmitters to leg-rings of adult Cape gannets had no observable negative effects on the adults or their chicks in terms of adult body condition, nest attendance and foraging trip durations, or chick growth and survival. Furthermore, the frequency distribution of behaviour bout (foraging trip and nest attendance) durations was no different between automated and directly observed data. However, the automated method did record shorter behaviour bouts, largely attributed to the increased likelihood of direct observations missing birds returning briefly to their nests during older chick provisioning. Additionally, foraging trip duration was highly correlated to foraging effort in terms of time spent resting on the sea surface, flying and diving. The automated method therefore appears to be a good reflection of direct nest attendance observations and foraging effort. Cape gannet time-activity budgets were related to chick age and parental sex. Especially as chicks neared fledging, females spent significantly longer periods of time foraging than males, with males consequently provisioning their chicks more often. Furthermore, adults departing their nests earlier spent more time away from the nest foraging as more same-day daylight hours were available. Chick growth was a function of parent foraging trip duration and associated prey delivery rates. Chick survival was most strongly affected by the amount of time which chicks were left unattended by both parents and consequently exposed to predation by kelp gulls (Larus dominicanus) or to adverse weather conditions. Additionally, for females (but not males) there appeared to be a trade-off between foraging trip duration and chick survival. The Cape gannet appears to demonstrate a strategy whereby the costs of reproduction to the female are shifted towards male-dominated chick provisioning as the chick nears fledging. Drivers of time-activity budget variability such as chick age and parental sex therefore need to be considered if using data on foraging trip duration as a proxy of foraging effort and prey availability.
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Michel, Pascale, and n/a. "Habitat selection in translocated bird populations : the case study of Stewart Island robin and South Island saddleback in New Zealand." University of Otago. Department of Zoology, 2006. http://adt.otago.ac.nz./public/adt-NZDU20070118.143501.
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The choice of a place to live and reproduce is crucial for species� survival in providing them with adequate resources and shelter from predators or climatic conditions. Determining habitat suitability in endangered species is important for the success of translocation as a conservation tool. In addition, understanding mechanisms (source/sink system versus ecological traps) that drive habitat selection in translocated animals may be critical to population viability. In New Zealand, where ecosystems are highly vulnerable to extinction, habitat restoration on predator-free off-shore islands is an important recovery tool. Therefore, there is a need to understand the relationship between the establishment of the translocated populations and the characteristics of their new environment.
Previous research indicated that re-introduced populations of Stewart Island robin (Petroica australis rakiura - Toutouwai) and South Island saddleback (Philesternus carunculatus carunculatus - Tieke) on Ulva Island (Stewart Island), New Zealand, showed preferences for coastal habitats that were characterized by low-lying dense vegetation and open ground cover. In this study, we further investigated territorial establishment in these two populations since re-introduction and looked at how birds utilised the landscape. I hypothesised that sites colonised soon after re-introduction were of high quality and later on, birds moved into unsuitable habitats. I defined habitat quality at a micro-scale in terms of vegetation structure, nest characteristics and food availability. I modeled bird presence and nesting success in relation to habitat components to determine factors in the environment that influenced breeding site selection and contributed to successful nesting in these two species. I discussed results in comparison to similar bird-habitat models developed for the South Island saddleback population on Motuara Island (Marlborough Sounds) and examined explanatory variables in each model.
Translocated birds in the three studied populations first established territories in coastal scrub, and in the following years moved into larger coastal forest stands. Although vegetation structure was the primary variable explaining site selection in these populations, vegetation composition should still be considered important as it dictated the suitability of nesting substrate and the availability of food items. There was no evidence that first-colonised areas were more suitable habitats, and I concluded that these cases could not be used as examples of ecological traps. Instead, results suggested that with increased density robins and saddlebacks on Ulva have more recently settled in sites less suitable to nesting and foraging, thus underlying a source/sink structure. However, the sparse distribution of food items on Motuara contributed to a lack of territorial behavior and environmental effect on breeding success; therefore a source/sink system could not be confirmed in this population. I recommended that future translocation sites give preference to mixed-size stands with broadleaved species that are characterised by dense canopy below 4 m height and with suitable cavities in live trees. Lastly, due to robins� and saddlebacks� attraction to conspecifics and their territorial behavior, resources evenly distributed across the landscape could also increase their survival and reproductive success.
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Frentiu, Francesca D. "Adaptive morphological evolution in an island bird (Zosterops lateralis chlorocephalus) : a quantitative genetic approach /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18184.pdf.
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Ralph, Mark Shaun. "Aspects of the breeding biology of the African penguin on Bird Island, Algoa Bay." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/840.
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It is important to the survival of the Africa Penguin (Spheniscus demersus) population that breeding at the nest site is successful and that large numbers of chicks are fledged into the breeding population. Nest distribution on Bird Island is not random and locality preferences for breeding exist. Although it seems that sufficient area exists on Bird Island for penguin nests, it can hardly be considered as suitable to optimise breeding. During prolonged heat conditions, breeders relocated to nest sites that were sheltered. Nests that were below ground in burrows was the only habitat that did not suffer nest desertion whilst all the other habitat types (including those that were sheltered) experienced 2-3 fold declines in nest numbers. Nests density and the selection of suitable nest sites are significantly influenced by the stage of breeding that the majority of birds are in, yet nests that are shaded, well-ventilated and protected seem to be the most preferred sites for breeding. Adults that attempt to breed are considered then to be in a healthy condition and will usually lay a double clutch (Randell 1983). The frequency of double clutches being laid during the peak breeding attempt was significantly higher compared to the replacement one. Breeding failure was fairly similar to breeding success during the incubation stage for nests with double clutches however, was substantially higher in single clutches. The growth rate of chicks was best fit to the von Bertalanffy growth curve in 90 percent of the cases. The overall growth rate of chicks from double broods was faster than from single broods, however was not significant. A-chicks maitain a high growth rate until they fledged. Yet, the sibling B-chick recorded the lowest growth rate of the successfully fledged chicks and up to until day 30 recorded a similar weight to those chicks that failed to fledge. Contrary to findings of Randall (1983), chicks from single broods delayed fledging, recorded lowest overall growth rates and experienced the greatest weight loss of all groups, yet fledged successfully. In order for chicks to fledge successfully, they needed to obtain a weight of 1060 g before day 30.5 in their growth cycles to avoid death due to startvation later on. Single chicks that are raised from a double cluth, fledged more other than chicks raised from a single clutch. Unfit or ill-adapted breeders that are marginal in the capabilities of raising offspring, already manifest in a small clutch size and offspring unable to obtain adequate weights during the initial stages of growth.
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Maraj, Ramona. "Bird habitat associations in managed Douglas-fir forests on the east coast of Vancouver Island." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51410.pdf.
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Armstrong, Claire. "The role of pathogens in shaping genetic variation within and among populations in an island bird." Thesis, University of East Anglia, 2018. https://ueaeprints.uea.ac.uk/69970/.
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This thesis aimed to investigate the role of pathogen-mediated selection in shaping patterns of genetic variation in Berthelot's pipit Anthus berthelotii, a passerine endemic to the Macaronesian archipelagos of the Canary Islands, Madeira, and Selvagens. I used restriction-site associated DNA sequencing (RAD-seq) to investigate patterns of neutral diversity among Berthelot's pipit populations, and in its sister species, the tawny pipit Anthus campestris, finding a loss of genome-wide diversity associated with colonisation history and genetic bottlenecks. I performed genome-wide association studies (GWAS) to identify genomic regions associated with malaria infection and bill length. I detected signatures of divergent selection around potential candidate genes related to immunity and metabolism, suggesting that these traits play oles in divergence and adaptation in this species. I then characterised genetic variation in Berthelot's and tawny pipits at avian β-defensins (AvBDs), a key gene family of the innate immune system. Allelic richness decreased with increasing numbers of bottlenecks. However, some AvBDs showed elevated nucleotide diversity compared with genome-wide trends. We found no evidence of local adaptation or balancing selection in Berthelot's pipits, suggesting that AvBD variation in this species is predominantly driven by genetic drift. Finally, I investigated whether malaria was driving fine-scale patterns of variation at SNPs identified in the earlier GWAS, and at the toll-like receptor 4 (TLR4) locus, a pathogen recognition receptor of the innate immune system, in two island populations. Both islands showed potential associations between malaria infection and TLR4 variation. In contrast, there was no association between a GWAS SNP and malaria risk in Tenerife, whereas in Porto Santo, the opposite trend to the original GWAS was found, potentially indicating local adaptation and population divergence. Overall, the evidence suggests that although functional variation in Berthelot's pipits is strongly influenced by demographic history, adaptation to pathogens may be occurring within and between populations.
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Lessig, Heather. "Species Distribution and Richness Patterns of Bird Communities in the High Elevation Forests of Virginia." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35899.
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Island biogeography theory predicts that the patterns and distributions of spatially isolated populations are governed by large scale processes. The high elevations forests in the Southern Appalachians represent a series of naturally fragmented islands that harbor many isolated populations of species at the southern limits of their range. Understanding the governing forces of population dynamics in this region will enhance the probability of species persistence in the face of threats such as global warming and human development. We surveyed bird populations across multiple elevations in Virginia and combined this with a multi-scale habitat analysis to determine influences of species presence and species richness. We detected 101 species across the elevation gradient, including 12 species with special conservation status and ten species whose presence increased with increasing elevation. These ten elevation sensitive species responded to habitat variables at both the microhabitat and landscape scale, with species-specific patterns of habitat variable correlation emerging. Habitat type was least effective in predicting species presence for any elevation sensitive species. Species richness declined over the elevation gradient until the highest elevations, where this trend reversed and richness began to increase. This pattern was driven by an increase in short-distance migrants beginning at mid-elevations, which ultimately overpowered a corresponding decrease in long-distance migrants beginning at similar elevations. Habitat analysis linked these patterns to a preference of short-distance migrants for smaller, more isolated non-forested patches, and a historical lack of persistence for long-distance migrants. Conservation and management decisions for the region should focus on a multi-scale approach that preserves all habitat types for continued species presence and high species richness, although the persistence of particular elevation sensitive species is compounded by unique species-habitat relationships and the perception of islands as species-specific. Continued monitoring of these fragmented populations in light of both short- and long-term threats which span multiple scales of influence will maintain high species richness and ensure the persistence of crucial breeding habitat.Master of Science
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Kellermann, Jherime L. "Spatiotemporal and Phenological Pattens of Bird Migration and the Influence of Climate and Disturbance in the Madrean Sky Island Archipelago and North American Southwest." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/268552.
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Distributional and ecological dynamics of Neotropical migratory birds at stopover sites where they maintain critical fat reserves during migration remain poorly understood in North American aridlands. I examined spatiotemporal abundance and timing of migrants relative to 1) upland and riparian habitats, 2) post-fire landscape mosaics, and 3) phenological synchrony and overlap of migration with tree flowering in southeastern Arizona's Madrean Archipelago (2009-2011), and 4) abundance, habitat breadth, and foraging substrates relative to tree flowering along the Colorado River in southwestern Arizona and northwestern Sonora, Mexico (2000-2003). I explored these dynamics relative to local weather conditions and El Niño Southern Oscillation (ENSO) climate phenomena. In Madrean habitats, migrants showed three non-exclusive responses to high precipitation, snowfall, and low minimum temperatures associated with El Niño in 2010; migration timing adjustments, habitat shifts, and reduced abundances suggesting migration route shifts. Foliage-gleaning insectivores were most abundant in high severity burns, disproportionate to their availability, and decreased with time since fire (TSF); flycatchers were most abundant in low-moderate severity and increased with TSF. Migrant abundance increased with tree flowering. Phenological overlap declined with increasing difference in timing of these events. Overlap was lowest in 2011 in riparian habitat due to low willow (Salix goodinggii) flowering, despite high migrant abundance, but lowest in 2010 in montane conifer, despite high pollen cone production by Douglas-fir (Pseudotsuga meziesii), suggesting temperature limitation of insect abundance at high elevations, but water limitation of plant phenology at lower elevations. Along the Colorado River, migrant abundance and habitat breadth had inverse positive and negative quadratic relationships, respectively. Abundance increased with tree flowering, but only in 2003 during severe drought. Habitat breadth increased with monsoon precipitation. Foraging substrate use tracked flowering, shifting from willow to mesquite (Prosopis sp.); the overlap coincided with peak abundance and narrowest habitat breadth. Maintenance of diverse vegetation and post-fire landscape mosaics in the Madrean Archipelago should benefit migratory bird diversity. Flowering phenology likely provides large-scale cues of local-scale stopover habitat condition associated with interannual climatic variation. Management and restoration of upland habitats and large riparian woody perennials will be critical for migratory bird conservation in aridlands.
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Klövekorn, Henning Andreas. "Endangered bird species in South Australia : are current recovery practices for the Orange-bellied parrot and Kangaroo Island glossy black cockatoo succeeding? /." Title page, contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09ENV/09envk66.pdf.
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Laws, Rebecca, and n/a. "The causes of nest failure and effects of inbreeding depression in a historically small population of New Zealand Stewart Island robins." University of Otago. Department of Zoology, 2009. http://adt.otago.ac.nz./public/adt-NZDU20090813.114240.
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Inbreeding depression is one of the factors that can increase the risk of extinction of small populations, and therefore understanding its effects is currently an important issue in conservation biology. Until recently, few studies on inbreeding depression were carried out in wild populations. These recent studies have highlighted the variability in detecting inbreeding depression among natural populations and the multitude of factors that can influence its expression. Many of the factors affecting inbreeding depression in wild populations remain largely unexplored and most of the recent studies in this area have tended to focus on incidents of inbreeding in populations with a history of large population size.
The aim of this study is to investigate the relative importance inbreeding depression has had on individual fitness parameters in a population of New Zealand's Stewart Island robins Petroica australis rakiura introduced to Ulva Island. This island population has historically gone through several population bottlenecks. Four main factors that potentially influence the rate of inbreeding and the extent of inbreeding depression, were investigated: environmental variability, life history stage, genetic load and dispersal. Generalized Linear Mixed Modelling was first used to determine how weather affected nest survival. Weather effects were then incorporated into models containing demographic factors to control for environmental variability, and finally parental, maternal and paternal inbreeding co-efficients (=f) were added to models to determine the relative importance of inbreeding depression. Interactions between inbreeding depression and environmental factors were explored. Three different life history stages were compared to determine the differences in inbreeding depression at each stage as well as cumulative effects over time. The genetic load of the population was estimated using lethal equivalents allowing for standardised comparison of inbreeding depression with other species. The likelihood of inbreeding in the population was also explored by investigating the factors affecting dispersal patterns and evaluating evidence for inbreeding avoidance.
Inbreeding depression was found to be mild in the robin population. Weather did not have strong effects on nest survival or interactions with inbreeding. Female age was the only factor interacting with inbreeding, with younger inbred females experiencing significantly reduced offspring juvenile survival. Parental and paternal f did not significantly affect brood survival at any life history stage, however, maternal f showed significant effects on nest juvenile survival with the strongest effect occurring when survival was examined cumulatively over all life history stages. The Stewart Island robin had a relatively low lethal equivalent value compared to the closely related North Island robin and other avian species. This difference was associated with the Stewart Island robin having a low genetic load, most likely due to historical genetic purging during periods of population bottleneck. The Ulva Island robin population did not appear to be avoiding inbreeding through dispersal. Dispersal distance was most strongly influenced by the location of the natal nest of the dispersing offspring.
In conclusion, the genetic history of the population was likely to have had the strongest impact on the severity of inbreeding depression in the Ulva Island robin population. The results of the thesis highlight the need to examine a number of factors to be able to explain variability in inbreeding depression among populations.
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Rowe, Daniel. "Constant Motion." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3120.
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This thesis contains my writings and concept development, as it relates to personal history, time and animated art. This is explored through various methodologies, including short story and Zen meditative writing. As a companion to my recent thesis exhibition, this paper looks to make logical, emotional and spiritual connections between my art practice, ritualized cultural tropes and contemporary views of mortality.
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Stephens, Jaime L. "A comparison of bird abundance and nesting in harvest units, habitat islands, and mature coniferous forests in southwestern Oregon /." View full-text version online through Southern Oregon Digital Archives, 2005. http://soda.sou.edu/awdata/050801c1.pdf.
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Thesis (M.S.)--Southern Oregon University, 2005."A thesis submitted to ... Southern Oregon University in partial fulfillment of the requirements for the degree of Master of Science ..." Includes bibliographical references (leaves 70-73). Also available via Internet as PDF file through Southern Oregon Digital Archives: http://soda.sou.edu. Search Bioregion Collection.
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Johnson, Luanne PhD. "The Behavioral Ecology and Population Characteristics of Striped Skunks Inhabiting Piper Plover Nesting Beaches on the Island of Martha's Vineyard, Massachusetts." Antioch University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=antioch1463581942.
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Walker, Kevin R. "Climatic Dependence of Terrestrial Species Assemblage Structure." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/23697.
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An important goal of ecological studies is to identify and explain patterns or variation in species assemblages. Ecologists have discovered that global variation in the number of species in an assemblage relates strongly to climate, area, and topographic variability in terrestrial environments. Is the same true for other characteristics of species assemblages?
The focus of this thesis is to determine whether species assemblage structure, defined primarily as the body mass frequency distributions and species abundance distributions relate in convergent ways to a set of a few environmental variables across broad spatial scales.
First, I found that for mammals and trees most of their geographic variation across North and South America in assemblage structure is statistically related to temperature, precipitation, and habitat heterogeneity (e.g. different vegetation types) in convergent ways.
I then examined bird assemblages across islands and continents. Despite the evolutionary and ecological differences between island and continental assemblages, I found that much of the variation in bird assemblage structure depends on temperature, precipitation, land area, and island isolation in congruent patterns in continent and island bird assemblages.
Frank Preston modeled species richness based on the total number of individuals and the number of individuals of the rarest species. Building on Preston’s model, Chapter 2 hypothesized that gradients of diversity correlate with gradients in the number of individuals of the rarest species, which in turn are driven by gradients in temperature and precipitation. This hypothesis assumes that species abundance distributions relate to temperature and precipitation in similar ways anywhere in the world. I found that both the number of individuals of the rarest species (m) and the proportion of species represented by a single individual in samples of species assemblages (Φ) were strongly related to climate. Moreover, global variation in species richness was more strongly related to these measures of rarity than to climate. I propose that variation in the shape of the log-normal species abundance distribution is responsible for global gradients of species richness: rare species (reflected in m and Φ) persist better in benign climates.
Even though body mass frequency distributions of assemblages show convergent patterns in relation to a set of a few environmental variables, the question remains as to what processes are responsible for creating the geographical variation in the body-size distribution of species. Several mechanisms (e.g. heat conservation and resource availability hypotheses) have been proposed to explain this variation. Chapter 5 tested and found no empirical support for the predictions derived from each of these mechanisms; I showed that species of all sizes occur across the entire temperature gradient.
In conclusion, assemblage structure among various taxonomic groups across broad spatial scales relate in similar ways to a set of a few environmental variables, primarily mean annual temperature and mean annual precipitation. While the exact mechanisms are still unknown, I hypothesize several to explain the patterns of convergent assembly.
Résumé
Un but important de l'écologie est d'identifier et d'expliquer la variation de premier ordre dans les caractéristiques des assemblages d'espèces. Un des patrons ayant déjà été identifié par les écologistes, c'est que la variation mondiale de la richesse en espèces est liée à la variation du climat, de l'aire et de la topographie. Est-ce que d'autres caractéristiques des assemblages d'espèces peuvent être reliées à ces mêmes variables?
Le but de cette thèse est de déterminer si la structure des assemblages d'espèces, ici définie comme la distribution des fréquences de masse corporelle ainsi que la distribution d'abondances des espèces, est reliée de manière convergente à un petit ensemble de variables environnementales, et ce, partout dans le monde.
D'abord, j'ai déterminé que, pour les mammifères et les arbres, la majorité de la variation géographique dans la structure des assemblages d'espèces est reliée statistiquement à température, précipitation, et l’hétérogénéité du couvert végétal , et ce, de manière convergente pour l'Amérique du Nord et du Sud.
Je me suis ensuite penché sur l'assemblage des oiseaux sur les îles et les continents. Malgré les larges différences évolutives et écologiques qui distinguent les îles des continents, je démontre que la majorité de la variation dans la structure des assemblages d'oiseaux dépend de la température, la précipitation, la superficie et l’isolation de façon congruente sur les îles et les continents.
Frank Preston a modélisé la richesse en espèces d'une localité, basée sur le nombre total d'individus ainsi que le nombre d'individus de l’espèce la plus rare. En s'appuyant sur les modèles de Preston, Chapître 3 propose une nouvelle hypothèse voulant que les gradients de diversité dépendent des gradients du nombre d'individus de l’espèce la plus rare. Celle-ci dépend des gradients de température et de précipitation. Cette hypothèse repose sur le postulat que la distribution d’abondances des espèces dépend de la température et la précipitation, et ce, de la même manière n’importe où au monde. J’ai mis en évidence que le nombre d’individus de l’espèce la plus rare (m), ainsi que la proportion d’espèces représentées par un individu unique () dans des échantillons locaux étaient fortement reliés au climat. D’ailleurs, la variation globale de la richesse en espèces était plus fortement reliée à ces indices de rareté qu’au climat. Je propose que la variation dans la forme de la distribution log-normale d’abondances d’individus soit responsable des gradients mondiaux de richesse en espèces. En d’autres mots, les espèces rares (indiquées par m et ) persistent mieux dans des climats bénins.
Malgré que la distribution des fréquences de masse corporelle des assemblages d'espèces soit liée de manière convergente à seulement quelques variables environnementales, la question demeure à savoir quels processus sont responsables des gradients géographiques de variation en masse corporelle des espèces. Plusieurs mécanismes ont été proposés pour expliquer cette variation. Dans Chapitre 5, j'ai testé les prédictions dérivées de chacun de ces mécanismes sans trouver de support empirique pour aucun. Je démontre aussi que des espèces de toutes tailles se retrouvent sur le gradient de température en entier.
En conclusion, la structure des assemblages d'espèces, pour différents groupes taxonomiques et à travers le monde, est liée de façon similaire à un petit nombre de variables environnementales. Bien que les mécanismes soient encore inconnus, j'en propose plusieurs pouvant expliquer ces patrons d'assemblages convergents.
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Lin, Fang-yee. "'Islands' in an island: multiscale effects of forest fragmentation on lowland forest birds in Taiwan." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/50986.
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Intensive agricultural developments and increasing human population has caused severe lowland-forest loss and fragmentation in the western coastal plain in Taiwan over the past centuries. The goal of this study is to explore the multiscale impacts of forest fragmentation on species richness and community composition of lowland-forest birds in Taiwan. At a regional scale, Island Biogeography Theory was applied to examine area and isolation effects on species richness of lowland-forest birds using bird data derived from Breeding Bird Survey Taiwan in 2009 and 2010. I also investigate the differential responses of two functional groups (forest specialists and generalists) to area and isolation effects Furthermore, I examine the relative influences of environmental variables at regional, landscape and local scales on avian community indices and composition in northern Taiwan with a hierarchical multiscale approach. Finally, species vulnerable to forest fragmentation and the ecological traits associated with specie vulnerability to forest fragmentation were identified.Only forest specialist species responded to the regional-scale area and isolation effects. The species richness of forest specialists increased with the size of forest islands, and the community similarity of forest specialist species declined with increasing the distance from the sources of immigrants. Structurally isolated forests may not function as real habitat patches from the view of forest generalists because of their flexibility in utilizing the non-forest matrix. After accounting for the influences of environmental variables at other spatial scales, the regional-scale isolation effect still played a key role in determining avian community composition based on the
presence/absence data set. But local-scale forest condition also explained a considerable amount of variability in the presence/absence data set. The regional-scale isolation effect, however, didn\'t show significant influences on community composition based on the abundance data set. In contrast, the landscape-scale variables explained the largest amount of variability in the abundance data set at the entire community level. There were six bird species (Parus varius, Dicrurus aeneus, Treron sieboldii, Pericrocotu solaris, Erporniszan tholeuca and Alcippe brunnea) whose occurrence and abundance were both vulnerable to forest fragmentation. Habitat specialization was the ecological traits most strongly associated with their vulnerability
Ph. D.
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Whitwell, Sarah Margaret. "The impact of isolation from mammalian predators on the anti-predator behaviours of the North Island robin (Petroica longipes) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Auckland, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1142.
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Conservation in New Zealand has begun to focus heavily on the restoration of degraded mainland ecosystems and the reintroduction of native species that have become locally extinct. In many cases the individuals that are selected for reintroduction are harvested from ‘mammal-free’ offshore islands. This thesis examines the effects of isolation from mammalian predators on the predator avoidance behaviours and predator recognition abilities of New Zealand birds using the North Island robin as a model. It also investigates whether any effects of isolation from mammalian predators has a lasting impact on mainland populations founded by individuals from offshore islands. Nest site selection behaviours were compared across three populations that are exposed to different suites of predators and have differing translocation histories; Benneydale, Tiritiri Matangi and Wenderholm. Point height intercept and point-centred quarter surveys were used to compare habitat availability between the sites and to compare nest sites with the available habitat. Eight nest characteristic variables were also compared across the three sites using a principle component analysis. Benneydale nests were located higher in the trees and were more concealed than nests at the other two sites. Nests on Tiritiri Matangi were supported by large numbers of thin branches and were located toward the periphery of the nest tree. Unfortunately these differences are very difficult to interpret due to a high degree of variation in the habitat types present at the three sites. The anti-predator behaviours initiated in response to a model stoat, model morepork and control were used to test the ability of nesting robins to recognise the threat that each of these treatments might pose to nest success. Behavioural variables were compared between Benneydale, Tiritiri Matangi and Wenderholm using a response intensity scoring system and a principle component analysis. The results indicated that isolation from mammalian predators on Tiritiri Matangi has suppressed the ability of robins on the island to recognise the predatory threat posed by a stoat. They also suggest that the intense mammal control carried out at Wenderholm may have inhibited the ability of local robins to produce strong anti-predator responses when faced with a stoat.
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Baillie, John Edward Michener. "Persistence and vulnerability of island endemic birds." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248461.
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Fluen, Tommy. "A comparative analysis of evolutionary changes in island birds." Thesis, University of Canterbury. Biological Sciences, 2008. http://hdl.handle.net/10092/1881.
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The evolutionary pressures of islands are often considered to be quite different to those found in continental systems. The insular flora and fauna and their characteristics that have resulted from this unique suite of pressures have puzzled scientists for centuries. This thesis uses the comparative approach to examine how island passerine birds differ from continental birds. Birds on islands like New Zealand have had an evolutionary history free from mammalian predators, in contrast to continental European species that co-evolved with mammals. Given this difference I examined how island birds differed from continental birds in three ways: sound, smell and appearance. I first looked at differences in the begging vocalisations of New Zealand nestling birds and compared these to the vocalisations of nestling introduced European birds. I expected that introduced species should produce less conspicuous calls given their co-evolutionary history with mammalian predators, while New Zealand birds should have comparatively more conspicuous begging calls. In fact, the calls of the two groups of birds were relatively similar. I then looked at the differences in the volatility ("smell") of preen waxes between native New Zealand species and introduced European species. I tested the prediction that New Zealand birds, which did not evolve with predatory mammals that located prey by smell, should produce preen waxes that do not function as 'olfactory crypsis' as found in continental birds. As found previously, introduced species adopt an 'olfactory crypsis' regime in by producing less volatile waxes during incubation. In contrast, most native species showed no shift in wax volatility, with one species even becoming more volatile in the breeding season, supporting a role of predation risk in the evolution of bird odours. Finally, I conducted a survey of evolutionary changes in appearance between insular and continental birds across a variety of isolated island groups, I compared changes in size, mass, wing length, bill size, carotenoid pigmentation, melanin pigmentation and 'dullness'. I found that island species were significantly larger, with larger bills than their continental counterparts. I also found that carotenoids decreased, and melanin pigmentation significantly increased, resulting in 'duller' island species. The reasons for these changes are not clear but highlight how island environments must differ in selective pressures from that encountered by birds on the continents. Overall my findings confirm that island species differ from continental species, and this extends to both their appearance, and somewhat surprisingly, their smell. My work raises a number of additional avenues for research, including a need to investigate the causes of changes exhibited by island birds.
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Thierry, Aude. "Predation risk and the evolution of odours in island birds." Thesis, University of Canterbury. School of Biological Sciences, 2014. http://hdl.handle.net/10092/10385.
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It is only recently that studies have explored the use of olfaction in birds. Birds are now known to use odour cues for navigation, and locating food. Odours produced by the birds themselves can also function in nest recognition and even mate choice. The odours of most birds stem from the preen wax produced by the uropygial or preen gland. The wax is comprised of a complex mixture of esters and volatiles, and is known to vary in some species with age, sex, season, or environmental conditions. Its function has been associated with feather maintenance, but it may also play a role in sexual selection and chemical communication. In this thesis, I used the preen gland and its preen wax to perform comparative studies on the evolution of odours between island birds and their continental relatives. I used the birds of the Oceania region as a model system, where most passerines originated from continental Australia but have colonised numerous surrounding islands such as New Zealand and New Caledonia. As islands generally lack mammalian predators, and have less parasites and less interspecific competition than continents, these differences in environmental conditions likely shaped functional differences in the preen gland and its products. I measured the size of the preen gland and collected preen wax from a variety of forest passerines in Australia, New Zealand and New Caledonia. I found that island birds have larger preen glands and therefore likely produce more preen wax than their continental relatives. I also found that the preen wax composition differed among species, with a shift to birds on islands producing disproportionately lighter and more volatile compounds. I suggest that selection favoured the gain of more volatile molecules in island birds as they were released from the constraint to camouflage their odours that is imposed by mammalian predators on continental areas. It is possible that this also allowed greater communication through olfactory channels in island birds, and such communication is enhanced through the use of more volatile compounds. To support this hypothesis I showed that the South Island robin (Petroica australis) was able to detect and react to the odour of a conspecific (odours produced by preen wax) in the absence of any visual cues. From a conservation perspective, increased volatility of the preen waxes of island birds might place them at increased risk from introduced mammalian predators that use olfaction to locate their prey. However, in both laboratory tests using Norway rats (Rattus norvegicus), a common exotic predator, and in field trials using rodent tracking tunnels, I found only limited evidence to suggest the odour of island birds places them at greater risk, and more experiments are needed to test this hypothesis. Finally, my findings of more conspicuous odours in island birds suggest new avenues of research for their conservation, including whether island species that seem especially prone to predation have preen waxes (and thus odours) that are also especially attractive to exotic mammalian predators. Conservation programmes to protect endangered island birds may even benefit from considering whether olfactory cues can be minimised as a method of reducing predation risk.
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Jarl, Tobias. "En ny bild av islam?" Thesis, Malmö högskola, Fakulteten för lärande och samhälle (LS), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-32502.
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Denna uppsats fokuserar på hur bilden av islam och muslimer visas i läroböcker från 2001 och framåt. Syftet med uppsatsen är att se om de samhälleliga förändringarna efter attentatet mot World Trade Center 2001 har påverkat läromedlen. Undersökningen görs på läroböcker skrivna efter 2001 i ämnet religionskunskap. Läroböckerna är på gymnasienivå. Uppsatsens teoretiska utgångspunkt är Edward Saids teori om orientalism. Den används i en kvalitativ undersökning av materialet som undersöker vissa tematiska aspekter och bilderna i böckerna. Resultatet av undersökningen är att vissa delar av läroböckerna har förändrats och blivit mer nyanserade, framför allt de som rör politik och islam som en våldsbenägen religion, men andra aspekter har inte förändrats, såsom klädsel och utövandet av religionen.
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Patterson, Michael E. "Piping plover breeding biology and reproductive success on Assateague Island." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/43276.
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I studied the piping plover on Assateague Island during the 1986 and 1987 breeding seasons. In 1987, I estimated the population to be 69 pairs. During both years, plovers nested on only a few portions of the island. I think that this pattern of nesting was determined by the distribution of three types of foraging habitats: bayside mud and sand flats, saltwater pools formed by storm tides, and a drawn down waterfowl impoundment. Reproductive rates were lower than two recent estimates of the level necessary to maintain a stable population. The primary problem was poor nest success and the leading cause of nest loss was nest predation by red foxes (Vulpes vulpes) and raccoons (Procyon Iotor). I was not able to identify factors responsible for chick mortality, but my data show a relationship between chick survival and foraging habitat. Broods feeding on bayside foraging areas had a much higher survival rate than broods which did not have access to these areas. Management efforts should focus on reducing nest predation. Recent experiments have indicated that predator exclosures constructed around individual nests can be used to reduce nest predation. These exclosures should be tested on Assateague. Future research efforts should focus on the role of foraging habitat in breeding site selection and the relationship between chick survival and the type of foraging used.Master of Science
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Hochachka, Wesley Michael. "Determinants of fitness in an island population of song sparrows." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/30616.
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Patterns and causes of variation in the reproductive success of Song Sparrows (Melospiza melodia) are investigated in this thesis. The two general patterns looked for were: inter-annual variation in reproductive success, and repeatability of reproductive
success of individual parents. The specific problems addressed were: (1) whether intra-seasonal variation in reproductive success was the result of differences in the quality of parents or their territories; (2) whether nutritional condition of nestlings affected their subsequent survival; (3) whether variation in morphology of adult sparrows
was influenced by the conditions under which birds grew up; and (4) given the patterns discovered in the first three sections, how trade-offs between present and future reproduction constrain the effort expended by adult sparrows in reproduction.
Data used in this thesis came from a long-term (1975-present) descriptive study of the population of Song Sparrows living on Mandarte Island, B.C., Canada. Data on survival, reproductive success, and nestling and adult morphology were all available. The approach taken in the thesis was to search for systematic variation in the data, and from these patterns to make inferences about cause and effect.
The following conclusions are made: (1) the intra-seasonal decline in clutch size, observed in populations of many species of birds, was the result of poor birds or birds on poor quality territories both nesting later and laying smaller clutches; (2) nestlings in better nutritional condition had a higher probability of survival while under the care of their parents, than nestlings in poor nutritional condition; (3) the probability of survival of offspring after they left their parents' care was lower for young born later in the year, but this pattern is not caused by variation among parents or their territories (contrary to the cause of seasonal decline in clutch size); (4) morphology of birds as adults was affected by the environment that birds grew up in, with nutritional condition and population density while a nestling both affecting adult morphology; (5) the effort that parents expend on reproduction is constrained by ability to vary reproductive effort with date of nesting and parental age.Science, Faculty of
Zoology, Department of
Graduate
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Warren, Ben H. "Phylogeography and evolution of species-rich bird lineages of the western Indian Ocean islands." Thesis, University of East Anglia, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.398791.
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Nicholson, Lisa. "Breeding strategies and community structure in an assemblage of tropical seabirds on the Lowendal Islands, Western Australia." Thesis, Nicholson, Lisa (2002) Breeding strategies and community structure in an assemblage of tropical seabirds on the Lowendal Islands, Western Australia. PhD thesis, Murdoch University, 2002. https://researchrepository.murdoch.edu.au/id/eprint/228/.
Full textAbstract:
Information about tropical seabird communities is less abundant in the literature than for those that occur at higher latitudes. In research papers examining seabird breeding communities in tropical environments, it has been found that food availability was temporally and spatially variable in comparison to higher latitudes. This environmental variability would be expected to influence the life-history traits of tropical seabird species, and in turn, the structure of the communities in which they occur. To examine the impact of environmental variability upon the life-history traits and community structure of tropical seabirds, a comparative study of the breeding strategies of three tropical tern species and an outlier, shearwater species was carried out, at the Lowendal Islands, Western Australia (20 degrees 39'52S; 115 degrees 34'44E) between 1996 and 2000.
Bridled Terns Sterna anaethetus and Wedge-tailed Shearwaters Puffinus pacificus shared the life-history traits of migration or dispersal from the breeding colony and east-Indian Ocean metapopulation when not breeding, a summer breeding schedule, nest-site fidelity, concealed nest-sites, clutch size of one, offshore and pelagic foraging regime, and protracted post-natal growth. Crested Terns Sterna bergii and Lesser Crested Terns Stern bengalenis bred within the same colony and shared the life-history traits of presence at the breeding colony when not breeding, an autumn breeding schedule, change in colony site each season, open dense nest-sites, brood size of one. inshore foraging regime (as well as offshore for Crested Terns) and rapid post-natal growth.
It was found that each species experienced variation in nest-site occupancy and/or colony size, as well as variation in timing of breeding and breeding success between years. The effects upon each species seemed to operate independently, as concurrently breeding species did not appear affected by the same events, with the exception of cyclones. Late and/or poor breeding success in a species often coincided with oceanographic changes in the north-west region, such as fluctuations in the strength of flow and temperature of the Leewin Current. The Leewin Current is a warm water, low salinity current flowing southwards along most of the Western Australian coastline and has a stronger, warmer flow during El Nino Southern Oscillation (ENSO) events. Cyclone activity is also influenced by ENSO induced changes in the region's water temperature. Changes in the Leewin Current affected the timing of breeding for Wedge-tailed Shearwaters, and feeding conditions for all study species, presumably as a result of changes in prey availability, while cyclone events delayed breeding for Crested Terns and Lesser Shearwaters in the years studied. Cyclone events were the most obvious cause of re-laying in the case of Crested Terns and Lesser Crested Terns, and breeding failure in the case of Bridled Terns and Wedge-tailed Shearwaters. Breeding failure was common among later breeders in the Crested Tern colonies. Breeding success was relatively high for lesser Crested Terns in all years studied, as they hatched and fledged their chicks within the Crested Tern colony among the first wave of breeders.
There was some overlap in the diets and foraging grounds of the four study species. Crested terns and Lesser Crested Terns had the most similar diet, however, Crested Terns appeared to be the most opportunistic foragers, with the highest diversity of dietary prey, while Lesser Crested Terns diet consisted of a high proportion of atherinids. Bridled Terns has the next highest prey diversity, while half the diet of Wedge-tailed Shearwaters in this region, similar to conspecifics elsewhere, consisted of squid. Wedge-tailed Shearwaters were observed to be offshore and pelagic foragers. Their distribution in the waters surrounding the Lowendal Islands ranged to the full extent of observation transects(63 Km), and most likely beyond, excluding inshore waters (i.e. within 5 km of islands). They were not present in the vicinity of the Lowendal Islands when they were not breeding. Bridled Terns were observed to be offshore foragers, also ranging to the full extent of transects, and most likely beyond, occasionally including inshore waters. They were rarely observed when not breeding, with the exception of a small number of fledglings at the end of the breeding season. Crested Terns were observed to combine inshore and offshore foraging grounds, only ranging to the full extent of transects during their breeding season. Lesser Crested Terns were observed foraging inshore only.
Chick provisioning, in terms of meal size and frequency, varied between years and within seasons for all species. It was demonstrated that there were differences in mean corrected meal sizes between years for Wedge-tailed Shearwaters, and the same was inferred from chick growth curves for Bridled Terns. Wedge-tailed Shearwaters provisioned their chicks with larger meal sizes and a higher occurrence of double feeds in 1996/97 than in other years studied. The amount of time spent feeding chicks in the burrow by Wedge-tailed Shearwaters adults became shorter as the breeding season progressed. It was demonstrated that all three tern species increased the meal size delivered to chicks as they grew. Wedge-tailed Shearwaters did not increase meal size as the season progressed, however they did increase feeding frequency. The feeding frequency of Crested Terns was highest in 1999, nearly doubling that observed in 1997 and 1998. In 1998 Lesser Crested Terns fed their chicks up to six times more frequently than Crested Terns.
Chick growth varied for Wedge-tailed Shearwaters and Bridled Terns between seasons. Bridled Tern chicks grew more rapidly in 1997/98, were heavier and reached higher asymptotes for all linear parameters, the exception of wing length, than in 2000. On the other hand, Wedge-tailed Shearwater chicks grew more rapidly in 1999/2000 than in 1997/98, however, they attained similar asymototes for all parameters in both years. In the absence of repeat measures of same individuals, Crested Tern and Lesser Crested tern growth was examined using age categorization based on wing and tail feather development. Both species appeared to attain similar sizes at similar rates in each year.
Wedge-tailed Shearwaters accumulated weight up to 30% in excess of mean adult weight in all seasons. This is a common trait exhibited in procellarigorms, and some weight loss occurs prior to fledging. It is suggested, based upon evidence from other studies in which weight loss prior to fledging was found to be water loss, that lipid accumulation acts as an insurance for the period after fledging when young are leaning to forage for themselves.
The information gathered for this project found no direct evidence of competition among the species comprising the seabird community if Lowendal Islands. Niche overlap occurred amongst all species, particularly in the case of lesser Crested Terns and Crested Terns, which shared breeding phenology, breeding colonies, foraging grounds and dietary overlap. Niche overlap also occurred between Wedge-tailed Shearwaters and Bridled Terns, which shared breeding phenology and foraging grounds.
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Nicholson, Lisa. "Breeding Strategies and Community Structure in an Assemblage of Tropical Seabirds on the Lowendal Islands, Western Australia." Murdoch University, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040929.134652.
Full textAbstract:
Information about tropical seabird communities is less abundant in the literature than for those that occur at higher latitudes. In research papers examining seabird breeding communities in tropical environments, it has been found that food availability was temporally and spatially variable in comparison to higher latitudes. This environmental variability would be expected to influence the life-history traits of tropical seabird species, and in turn, the structure of the communities in which they occur. To examine the impact of environmental variability upon the life-history traits and community structure of tropical seabirds, a comparative study of the breeding strategies of three tropical tern species and an outlier, shearwater species was carried out, at the Lowendal Islands, Western Australia (20o3952S; 115o3444E) between 1996 and 2000.
Bridled Terns Sterna anaethetus and Wedge-tailed Shearwaters Puffinus pacificus shared the life-history traits of migration or dispersal from the breeding colony and east-Indian Ocean metapopulation when not breeding, a summer breeding schedule, nest-site fidelity, concealed nest-sites, clutch size of one, offshore and pelagic foraging regime, and protracted post-natal growth. Crested Terns Sterna bergii and Lesser Crested Terns Stern bengalenis bred within the same colony and shared the life-history traits of presence at the breeding colony when not breeding, an autumn breeding schedule, change in colony site each season, open dense nest-sites, brood size of one. inshore foraging regime (as well as offshore for Crested Terns) and rapid post-natal growth.
It was found that each species experienced variation in nest-site occupancy and/or colony size, as well as variation in timing of breeding and breeding success between years. The effects upon each species seemed to operate independently, as concurrently breeding species did not appear affected by the same events, with the exception of cyclones. Late and/or poor breeding success in a species often coincided with oceanographic changes in the north-west region, such as fluctuations in the strength of flow and temperature of the Leewin Current. The Leewin Current is a warm water, low salinity current flowing southwards along most of the Western Australian coastline and has a stronger, warmer flow during El Nino Southern Oscillation (ENSO) events. Cyclone activity is also influenced by ENSO induced changes in the regions water temperature. Changes in the Leewin Current affected the timing of breeding for Wedge-tailed Shearwaters, and feeding conditions for all study species, presumably as a result of changes in prey availability, while cyclone events delayed breeding for Crested Terns and Lesser Shearwaters in the years studied. Cyclone events were the most obvious cause of re-laying in the case of Crested Terns and Lesser Crested Terns, and breeding failure in the case of Bridled Terns and Wedge-tailed Shearwaters. Breeding failure was common among later breeders in the Crested Tern colonies. Breeding success was relatively high for lesser Crested Terns in all years studied, as they hatched and fledged their chicks within the Crested Tern colony among the first wave of breeders.
There was some overlap in the diets and foraging grounds of the four study species. Crested terns and Lesser Crested Terns had the most similar diet, however, Crested Terns appeared to be the most opportunistic foragers, with the highest diversity of dietary prey, while Lesser Crested Terns diet consisted of a high proportion of atherinids. Bridled Terns has the next highest prey diversity, while half the diet of Wedge-tailed Shearwaters in this region, similar to conspecifics elsewhere, consisted of squid. Wedge-tailed Shearwaters were observed to be offshore and pelagic foragers. Their distribution in the waters surrounding the Lowendal Islands ranged to the full extent of observation transects(63 Km), and most likely beyond, excluding inshore waters (i.e. within 5 km of islands). They were not present in the vicinity of the Lowendal Islands when they were not breeding. Bridled Terns were observed to be offshore foragers, also ranging to the full extent of transects, and most likely beyond, occasionally including inshore waters. They were rarely observed when not breeding, with the exception of a small number of fledglings at the end of the breeding season. Crested Terns were observed to combine inshore and offshore foraging grounds, only ranging to the full extent of transects during their breeding season. Lesser Crested Terns were observed foraging inshore only.
Chick provisioning, in terms of meal size and frequency, varied between years and within seasons for all species. It was demonstrated that there were differences in mean corrected meal sizes between years for Wedge-tailed Shearwaters, and the same was inferred from chick growth curves for Bridled Terns. Wedge-tailed Shearwaters provisioned their chicks with larger meal sizes and a higher occurrence of double feeds in 1996/97 than in other years studied. The amount of time spent feeding chicks in the burrow by Wedge-tailed Shearwaters adults became shorter as the breeding season progressed. It was demonstrated that all three tern species increased the meal size delivered to chicks as they grew. Wedge-tailed Shearwaters did not increase meal size as the season progressed, however they did increase feeding frequency. The feeding frequency of Crested Terns was highest in 1999, nearly doubling that observed in 1997 and 1998. In 1998 Lesser Crested Terns fed their chicks up to six times more frequently than Crested Terns.
Chick growth varied for Wedge-tailed Shearwaters and Bridled Terns between seasons. Bridled Tern chicks grew more rapidly in 1997/98, were heavier and reached higher asymptotes for all linear parameters, the exception of wing length, than in 2000. On the other hand, Wedge-tailed Shearwater chicks grew more rapidly in 1999/2000 than in 1997/98, however, they attained similar asymototes for all parameters in both years. In the absence of repeat measures of same individuals, Crested Tern and Lesser Crested tern growth was examined using age categorization based on wing and tail feather development. Both species appeared to attain similar sizes at similar rates in each year.
Wedge-tailed Shearwaters accumulated weight up to 30% in excess of mean adult weight in all seasons. This is a common trait exhibited in procellarigorms, and some weight loss occurs prior to fledging. It is suggested, based upon evidence from other studies in which weight loss prior to fledging was found to be water loss, that lipid accumulation acts as an insurance for the period after fledging when young are leaning to forage for themselves.
The information gathered for this project found no direct evidence of competition among the species comprising the seabird community if Lowendal Islands. Niche overlap occurred amongst all species, particularly in the case of lesser Crested Terns and Crested Terns, which shared breeding phenology, breeding colonies, foraging grounds and dietary overlap. Niche overlap also occurred between Wedge-tailed Shearwaters and Bridled Terns, which shared breeding phenology and foraging grounds.
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Bowie, Rauri Charles Kerr. "Birds, molecules, and evolutionary patterns among Africa's islands in the sky." Doctoral thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/6239.
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Includes bibliographical references.Combing results from phylogenetic and population level studies suggests that climatic cycling has had a profound influence on montane bird speciation in Africa. The results from this thesis suggest that there is deep genetic divergence between many clades (8-12%) of montane passerine birds in Africa, with some shallow divergence towards the tips (4-6%). For widespread species reciprocal monophyly has not been reached in some instances, but generally there is some support for the refuge idea that isolation (fragmentation) of montane forests has facilitated speciation. However, most speciation events happened well before the Pleistocene and therefore the Pleistocene Refugia Hypothesis is not appropriate as a model with which to explain patterns of montane bird diversification in Africa. Rather, both dispersal and vicariance have played important roles in shaping montane bird communities. Thus, a refugia type model does work, but only within the context of pulsed or cyclic expansion and contraction of montane forests, supported in thus study by the consistent recovery of spatially structured areas of endemism, despite varying temporal dynamics.
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Fenech, Natalino. "Bird shooting and trapping in the Maltese Islands : some socio-economic, cultural, political, demographic and environmental aspects." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/1588/.
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Moseley, Christina. "Comparing body condition and foraging ecology of two populations of Cape Gannets on Bird and Malgas Islands." Master's thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/4756.
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Cape gannets (Morus capensis) are one of the dominant seabirds in the Benguela current ecosystem and feed mainly on sardines (Sardinops sagax) and anchovy (Engraulis encrasicolus). Starting in the late 1990s the distribution of these fish shifted from the west coast of South Africa to the south-east coast. This has resulted in gannets on the west coast feeding extensively on fishery wastes, which slows the growth of chicks and decreases their fledging mass. I compared the foraging ecology, diet and body condition of adult Cape gannets from two colonies, one where individuals have been feeding on fishery wastes (hake) for several years (Malgas Island; west coast) and the other where individuals feed on natural prey (Bird Island; south coast). In October and November 2009, through the use of GPS loggers I compared the foraging behaviour of birds from the two colonies. I compared the diet of gannets at the two colonies, using stomach contents samples and an isotopic mixing model using stable isotope ratios of carbon and nitrogen in blood, feathers and potential prey. I also compared the body condition of adults by measuring pectoral muscle thickness and other morphological parameters. These results were analysed with data from a concurrent hydro-acoustic survey of the distribution and abundance of pelagic fish along the coast of South Africa. The hydro-acoustic survey showed that more than half of the sardine and anchovy stocks were present on the west coast for the first time in several years but that the overall biomass of these two species remained low in the southern Benguela. Stomach samples and isotopic analysis of blood showed that gannets at both colonies fed mainly on sardines during the study period. Long-term diet estimates from feather isotopes suggest that there was little hake in the diet of birds at Malgas Island, despite the direct diet samples showing that hake and saury dominated the diet over the preceding 10 months. This could be due to insufficient prey sampling or the diet samples not being representative of the gannet population as a whole. Gannets from Bird Island made longer foraging trips and flew further from their colony than did those from Malgas Island. Individuals from this colony had slightly greater pectoral muscle thicknesses and body masses (after controlling for size) than those from Bird Island, but 4 this was not significant. Despite gannets from Malgas Island relying on fishery wastes for a number of years, there has been little effect on body condition among breeding birds when compared with Bird Island gannets feeding on pelagic fish. Two possible reasons for this are that (1) when feeding on fishery wastes, adults decrease their reproductive effort to preserve body condition or (2) gannets on the west coast have regained body mass and pectoral muscle rapidly since the local recovery of sardines. It is likely that the gannets from Bird Island have greater foraging costs due to intra-specific competition for food as the colony has increased five-fold in size over the last 50 years. However, chick growth and adult body condition have been affected only marginally. Despite the presence of sardine and anchovy on the west coast, it is likely that Cape gannets are food limited, especially since there is also a strong spatio-temporal overlap of gannet foraging with the large commercial purse-seine fishery. Better spatial management of this fishery is necessary to ensure the persistence of seabirds and other top predators in the southern Benguela.
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Bollmer, Jennifer L. "Population genetics of island endemics neutral and major histocompatibility loci /." Diss., St. Louis, Mo. : University of Missouri--St. Louis, 2008. http://etd.umsl.edu/r2941.
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Wragg, Graham M. "The fossil birds of Henderson Island, Pitcairn Group, South Pacific : a chronology of human-caused extinctions." Thesis, University of Oxford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339060.
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Lehtonen, Sofia. "Islam - ett hot mot samhället? : en studie av Förbundet Humanisternas bild av islam." Thesis, University of Gävle, Department of Humanities and Social Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-3348.
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Denna uppsats syftar till att ge en bild av förbundet Humanisternas debatt och porträttering av islam och muslimer. Detta med hjälp av utländska ateister som även förekommit i förbundets egen tidskrift Humanisten. Mina frågeställningar är: Hur framställs islam och muslimer av media och av förbundet Humanisterna? Vilken kritik har framförts av Humanisterna angående islam och muslimer? Bidrar förbundet till en ökad schablonisering av islam och muslimer? För att nämna kortfattat vad jag kommit fram till kan det sägas att Humanisterna, när de skriver om islam eller muslimer, delvis är intoleranta i sin retorik. Den kritik som framförts mot förbundet är bland annat att de vill tvinga på en sekulär livsåskådning och att de tror dig ha ett slags monopol på sanningen. Eftersom den mediebild som redan existerar av islam och muslimer är negativt laddad, så hjälper Humanisterna till att öka den bild av islam som finns som den ”onda, mörka” religionen i vår tid, det vill säga, man bidrar till redan existerande schablonisering av muslimer.
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Gates, Jody. "An ecological study of Bush stone-curlews Burhinus grallarius on Kangaroo Island, South Australia." Title page, abstract and contents only, 2001. http://web4.library.adelaide.edu.au/theses/09SM/09smg259.pdf.
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Includes bibliographical references (leaves 150-161). Documents the historical distribution and subsequent decline of bush stone-curlews in South Australia, determines their current distribution and status on Kangaroo Island, their home range sizes and movements, the characteristics of foraging habitat, day roost areas and nest sites and the availability of habitat, the diet and food resources, and potential threats to the population. As a result of the findings of this survey, bush stone-curlews have been downgraded from endangered to vulnerable in South Australia.
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Harrison, Sofie Alice. "The influence of seabird-derived nutrients on island ecosystems in the oligotrophic marine waters of south-western Australia." Connect to thesis, 2006. http://portal.ecu.edu.au/adt-public/adt-ECU2007.0010.html.
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Dean, Tracey. "Second-growth habitat use and survival rates of migrant and resident land birds, North Andros Island, Bahamas." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ54614.pdf.
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Lundell, Anna. "Islam sett ur två perspektiv : om elevers bild av islam före och efter gymnasieundervisning." Thesis, Karlstad University, Faculty of Arts and Education, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1329.
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Undersökningar visar att många människor är negativt inställda till islam. Syftet med denna underökning är att ta reda på vilken bild eleverna har av islam före respektive efter religions-undervisningen om islam, samt att se om elevernas bilder har förändrats.
För att ta reda på detta har jag i två gymnasieklasser delat ut en enkät, dels före och dels ef-ter undervisningen.
Slutsatser som jag har kommit fram till genom min undersökning är att antalet elever som uppgav att de är positivt inställda till islam ökar från 13 % till 17 %. I det stora hela anser jag att elevernas föreställningar har blivit mer positiva. Därmed har undervisningen i skolan bi-dragit till att minska främlingsfientlighet och intolerans.
Contemporary surveys have shown that people in Sweden often assume a negative attitude towards Islam. The purpose of this study is to investigate the conceptions and attitudes stu-dents assume towards Islam before they study religions in Swedish schools and to what extent their attitudes are changing after the religious education.
Two groups of students at Upper Secondary School were given questionnaires with state-ments and questions about Islam before and after they pursued studies about the religion.
The result of the study displays that the number of students who stated they had a positive attitude towards Islam increased from 13 to 17 percentages after they pursued knowledge about the religion and the students’ view of Islam became generally more positive after their studies. The study thus indicates that religious education at Upper Secondary School has a significant role to change students’ negative attitudes and conceptions of religions. In exten-sion, these conceptual changes will, in line with the national curriculum, create understanding and tolerance towards religions in a multi-religious society.
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White, Robyn. "Response of New Zealand birds to the presence of novel predators." Thesis, University of Canterbury. Biological Sciences, 2014. http://hdl.handle.net/10092/10272.
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Predation is the highest cause of mortality for birds and can place intense selection pressures on their behavioural traits. A number of studies have shown that some animals have innate predator recognition, while others which are predator-naïve have been unable to adapt to the introduction of exotic predators. For my thesis, I firstly studied how eight species of introduced and native birds respond to model predators at their nests. This enabled me to determine whether the native birds have been able to adapt to introduced mammalian predators and have developed recognition of them being a threat. In most species, the reaction to the stoat (Mustela erminea) (an introduced predator) was similar to that of a model morepork (Ninox novaeseelandiae) (a native predator). This suggests these species can successfully recognise introduced mammals as a risk. It also allowed me to test whether recently introduced birds have any innate recognition of snakes, which are a significant nest predator in their native ranges but do not exist in New Zealand. I found that introduced birds did not appear to have any recognition of snakes as being a threat. These losses and gains of recognition may have been caused by evolutionary changes or they may be influenced by learning and experience.
Secondly, I examined how South Island robins (Petroica australis) on a predator-free island responded to predator models and compared this to the responses of robins on the mainland (where they co-occur with mammalian predators). The island birds were assumed to show the ancestral reactions to mammalian predators, while any differences in response shown by the mainland robins would indicate they had acquired these behaviours in response to increased predation risk. I found that the island robins did not appear to recognise or react to a taxidermic mount of a stoat while mainland robins did respond to the stoat, confirming that at least some native birds can develop recognition of novel predators.
Finally, I compared the personalities of South Island robins on a predator-free island and on the mainland (where mammalian predators are present). I tested where individuals placed on the ‘bold-shy’ continuum by observing their willingness and speed to approach a risky situation in order to collect food. Studies have shown that average personality between populations can differ where predation risk differs. I found that the island robins were on average bolder than mainland robins. They came nearer to the observer and were faster to approach and remove a food item, while mainland robins were less likely to approach, and those that did approach took a longer time. It is likely that these differences were due to selection pressures by mammalian predators favouring shy individuals on the mainland while other pressures such as interspecific competition favours bold individuals on the island. Personality has been shown to be genetic and heritable, however, learning and experience cannot be ruled out and may also play a part in influencing how personality is expressed.
Together, my results support the importance of historical and ontogenetic factors in influencing how predator recognition and personality traits are expressed.
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Nicholson, Lisa W. "Breeding strategies and community structure in an assemblage of tropical seabirds on the Lowendal Islands, Western Australia /." Access via Murdoch University Digital Theses Project, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20040929.134652.
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Burford, Miles Laurence Dalzell. "A comparative analysis of nesting life-history traits and the risk of predation among island and continental birds." Thesis, University of Canterbury. Biological Sciences, 2011. http://hdl.handle.net/10092/7394.
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Islands are home to one of the most endangered ecosystems today with high extinction rates, deteriorating biodiversity and high numbers of critically threatened species. Part of reason for the current situation is that island biotas are subject to different selective pressures compared to continental environments resulting in differences in life-history traits that may make island species especially susceptible to human-induced changes, especially the introduction of exotic predators. Although earlier studies have found a variety of behavioural and morphological differences between island and continental bird species, few studies have compared the reproductive life-history differences between insular and continental bird species. In this thesis, I compare how island passerines differ from continental passerines in some of their nesting life-histories. I focus my studies on New Zealand birds as this avifauna provides an excellent system to examine the nesting life-history traits of birds on islands that evolved without mammalian predators. At the same time, a large number of continental bird species have been introduced that evolved with mammalian predators, providing an opportunity to compare the two groups in a common environment. First, I compared predation rates of artificial nests baited with the preen waxes of New Zealand endemic birds and compared them to nests baited with continental preen waxes and control nests with no waxes. I expected that the artificial nests of the endemic species would be baited with more volatile (“smellier”) preen waxes and thus would depredated at a higher rate. The endemic nests were found to be predated in higher rates than the other nest treatments supporting the ‘olfactory crypsis’ theory. I then compared behavioural differences in flushing between endemic New Zealand species and continental species. I hypothesised that endemic New Zealand birds which evolved in a predator regime with avian predators but no mammalian predators would behave in ways that increase their vulnerability to mammalian predators compared to continental species. I found that New Zealand birds flushed from nests later or not at all compared to continental species, and returned earlier to the nests after flushing and did not alter their parental behaviours after flushing. All of these behaviours are likely to increase the vulnerability of endemic birds to introduced mammalian predators. Finally, I then took a broader perspective of island life history evolution and assessed evolutionary changes in the nest sizes of insular and continental bird species across a of islands. Island species were found to build larger nests with larger dimensions and overall ‘sizes’ than their continental relatives. The reasons for the changes in nest sizes may include the higher predation regimes encountered by continental birds, which puts a premium on minimising nest conspicuousness (and thus size). Overall, my findings confirm that life-history traits of island birds differ from those of continental species, and suggest that these differences arise from differences in the intensity of selection from predators. This highlights the unique features of island birds and identifies some of the attributes that may now make them vulnerable to introduced predators.
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Stewart, Annabelle Greer. "Dibblers on the Jurien islands : the influence of burrowing seabirds and the potential for competition from other species /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0066.
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Wright, Natalie A. "Gene flow, divergence, and morphological differentiation in birds on the islands of Trinidad and Tobago." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025110.
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Du, Toit Michelle. "Predatory interactions between Cape fur seals and seabirds at Ichaboe Island, Namiba." Diss., Pretoria : [s.n.], 2002. http://upetd.up.ac.zs/thesis/available/etd-11212005-150700/.
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