Dissertations / Theses on the topic 'Bird behaviour'
To see the other types of publications on this topic, follow the link: Bird behaviour.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Bird behaviour.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Barnett, Craig. "Food limitation and its effects on bird behaviour." Thesis, University of Canterbury. Zoology, 2001. http://hdl.handle.net/10092/6891.
Full textAbstract:
Stochastic dynamic programming (SDP) models make a number of predictions as to how birds should behave given different ecological conditions. These models are easily tested in the field, although there have been few studies of their predictions. In this thesis, I use predictions from SDP models to investigate the effects of food availability on three aspects of bird behaviour.
I first examined how supplemental food affects daily patterns of weight gain in birds. SDP models predict that birds should converge on the same mass by the end of the day irrespective of their fat reserves at the beginning of the day. I tested this prediction by comparing the mass trajectories of 12 male New Zealand robins (Petroica australis) when they started the day with differences in fat reserves. Fat reserves were manipulated experimentally by feeding birds one day and comparing them on two control days. I also examined caching behaviour and singing behaviour throughout the experiment in response. As predicted, body mass converged to a similar value at the end of the day regardless of initial mass. Fed males also sang more than on control days and stored less food over the course of the day.
Next, I examined the effect of supplemental feeding on the dawn chorus of silvereyes (Zosterops lateralis) by comparing the singing behaviour of 12 males between days with and without access to short-term supplementation. As predicted, I found that males increased their singing quantity and quality in response to supplementary food.
Lastly, I examined how food supplementation influences incubation behaviour. With periodic cyclic behaviour such as incubation, SDP models predict that birds should decrease the time spent off the nest when they have greater access to food. I tested this prediction by comparing the incubation behaviour of silvereyes on days when they received supplementation compared with days when they had no supplementation. As predicted, the renewal time (time taken for birds to renew their energetic reserves) decreased in response to supplementation, while overall investment increased.
The results from all chapters provide strong support for SDP models. These experiments show how even short-term changes in food availability can alter the behaviour of birds in ways that may ultimately be important in determining their reproductive success. My experiments reveal that there is much potential for the formulation and testing of these models in New Zealand species.
2
Dowell, Simon Derek. "The ontogeny of anti-predator behaviour in game bird chicks." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257814.
Full text
3
Bennun, Leon Alan. "Communal breeding in Grey-Capped Social Weavers (Pseudonigrita arnaudi)." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235975.
Full text
4
Roberts, J. G. "Studies of the flocking behaviour of Sanderlings, Calidris alba." Thesis, Durham University, 1990. http://etheses.dur.ac.uk/6248/.
Full textAbstract:
The behaviour of sanderlings, Calidris alba, was studied at Teesmouth, N. E. England. Flock sizes and within-flock spacing were related to factors such as substrate type, season, and prey distribution. Sightings of individually-identifiable colour-ringed birds showed that turnover was high. Individuals varied in their vagility and in the way in which they allocated their time between feeding sites. There was a high degree of consistency between winters in the distributions of individual birds. When individual sighting frequencies were taken into account, associations between individual sanderlings, in terms of both flock membership and of occurrences at the same sites on the same days, were non-significantly different from those expected by chance. Previously used methods for detecting non-random associations gave inadequate null models. Each individual appeared to make a decision about where to feed independently of the decisions made by any other particular individuals .A number of aspects of the dynamics of flocks were examined, including flock cohesion; how flocks built up and broke down; whether birds tended to move to the largest or smallest, the nearest or furthest flocks; the effects of disturbance on flock dynamics; and the relationship between group size and the distance flown between flocks. The responses of sanderlings to experimental disturbances tended to support the hypothesis that responses should be varied according to the costs and benefits of different courses of action rather than the hypothesis that birds should take flight as soon as a predator is sighted. Birds often break off from performing an activity in order to raise their heads (scan). Preening birds had shorter inter-scan intervals than feeding birds. Flock size and spacing explained only a small proportion of the variance in vigilance. Vigilance was greater in autumn than in winter. There was some evidence for both feeding and preening birds avoiding very short inter-scan intervals but not for the avoidance of long intervals. Sequences of inter-scan interval durations of preening birds were non-random.
5
Nazal, M. I. M. "Inter-relationships between plant fruiting patterns, bird foraging behaviour and fruit pests." Thesis, University of Liverpool, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372679.
Full text
6
Peake, Thomas M. "Variation in the vocal behaviour of the Corncrake Crex crex : potential for conservation." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363616.
Full text
7
Healy, Susan D. "A comparative study of brain and behaviour in food-storing animals." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276826.
Full text
8
Vennerholm, Linn. "Ontogeny of personality in red junglefowl chicks, Gallus gallus." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-78996.
Full textAbstract:
Many studies have been performed on animals to study their behavior, but not as many on the development of behavior, and not yet on chickens. Therefore, 42 red junglefowls were tested in three Novel Arena, Novel Object and Tonic Immobility tests to investigate the ontogeny of personality. Several behaviors were stable over time in the Novel Arena and Novel Object tests, and are a part of the bird’s personality, while other behaviors were plastic. The stability of the behaviors increased over time. The decrease in duration of the Tonic Immobility can be due to decreased stress during the length of the study. The study showed that personality can be detected early in a chicken’s life, even though a lot of the observed behaviors change. Further studies are needed to figure out duration of the stability and why certain behaviors are stable.
9
Lindblom, Emelie. "Traits and behaviour affecting social status in red junglefowl (Gallus gallus) hens." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79083.
Full textAbstract:
Social status is commonly established among individuals within groups of animals. Despite this common characteristic of social animals it is still unclear how individuals establish their status. I investigated the relationships between morphology, posture and behaviours with social status in red junglefowl hens. The hens tested were measured (weight, comb length, comb height and tarsus length) and exposed to three different behavioural tests (novel arena, novel object and interaction test). None of the morphological features were associated with social status. However, dominant hens initiated the first encounter in a dyad interaction and performed a higher proportion of aggressive encounters against the opponent. The dominant hens were also the ones displaying more spread tail feathers than the opponent after status being established. Aggressiveness and social status is strongly linked, showing that there is a scope of behaviours to affect the establishment of status.
10
Dahlqvist, Veronica. "Why is the bird (re)tweeting? : Creating a simulation of retweeting behaviour on Twitter." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129352.
Full textAbstract:
Social media is a big part of today’s society. But how do we know where the information we put out on the internet end up? This bachelor thesis is part of a bigger project where first year students at the cognitive science program at Linköping University will be taught about modeling of a social phenomenon. A lot can be learned about a phenomenon through modeling and simulation and that was the motivation for this bachelor thesis – to try to make a simulation of the spreading of information on social media. The social media platform that was selected was Twitter and the information spreading was narrowed down to retweeting of a tweet. The simulation was implemented in NetLogo – a modeling and simulation program. The simulation was based on important factors that contribute to a person’s willingness to retweet. The factors were found in published research reports. The result was a simulation of retweeting on Twitter that in some aspects resemble the real world phenomenon as it is depicted in published research reports. Towards the end of the report there is a discussion about what factors contributed to the resemblance or the difference between the world depicted in the published research reports and the simulation.
11
Jolliffe, Anna Ruth. "Food-storing and memory in the coal tit." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337597.
Full text
12
Stach, Robert. "Migratory routes and stopover behaviour in avian migration." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-126975.
Full textAbstract:
Migratory birds, some small and light weight as matchboxes, engage in seasonal inter-continental journeys in order to take advantage of the long summer days and abundance of food at northern latitudes to breed and raise their young, and then escape the harsh winters by migrating to lower latitudes. This thesis deals with two important aspects of migration, the routes taken during migration and the birds’ behaviour at stopovers. The migratory routes are for many species unknown, whole or in part, and this is especially true for species that migrate nocturnally. At stopovers birds replenish fuel reserves that powers migratory flight, and studying how birds utilise stopovers is important in order to understand how migration is organised. In this thesis I have used modern tracking technology to study both continental wide movements of thrush nightingales (Luscinia luscinia) and common rosefinches (Carpodacus erythrinus) using small light-level geolocators, and smaller scale movements at a single stopover site of garden warblers (Sylvia borin) using miniature radio-transmitters. I have also studied the fuelling behaviour of garden warblers during autumn migration in the field and in the lab, and great reed warblers (Acrocephalus arundinaceus) at a stopover site on Crete during spring migration after the Sahara crossing. The thesis discusses the significance of several aspects of migration shown by the birds that would have been very difficult to detect without the aid of modern tracking technology, such as loop migration, prolonged stops during migration, multiple wintering sites, and nocturnal relocations at stopover sites. Studies carried out at stopover sites also show that garden warblers and great reed warblers can attain large fuel loads even at sites where they have no barrier to cross and this might be a result of good foraging conditions. The thesis also highlights the importance of combining different techniques when studying stopover behaviour to get reliable estimates on stopover durations and fuel deposition rates as well as the importance of choosing sites preferred by birds when planning stopover studies.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript. Paper 5: Manuscript.
13
Wall, Helena. "Laying hens in furnished cages : use of facilities, exterior egg quality and bird health /." Uppsala : Department of Animal Nutrition and Management, Swedish Univ. of Agricultultural Sciences, 2003. http://epsilon.slu.se/a406.pdf.
Full text
14
Hedlund, Johanna. "Climate change effects on migratory birds and on the ecology and behaviour of the willow warbler (Phylloscopus trochilus)." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-120409.
Full textAbstract:
Recent global climate change is influencing the behaviour and ecology of species worldwide. Birds are typical systems to study in this context, as they are often migratory and thus subjected to a variety of environmental effects. This thesis employs the use of long-term ringing records, field observations, historical maps and historical volunteer observations with the aim of describing behavioural and ecological responses of birds to the current environmental change. An investigation into the spring arrival, reproduction and autumn departure in willow warblers (Phylloscopus trochilus) breeding at a southern study site in Sweden (65°N 18°E) showed that all three phenological events had advanced in parallel. Thus birds arrive earlier, start breeding earlier and leave Sweden earlier, with the breeding period staying the same in length. By teasing apart the migratory responses of different individuals, it became clear that particularly early arriving males and early departing juveniles had advanced migration. However, willow warblers migrating past a northern study site in Sweden (65°N 23°E) displayed no change in autumn departure. When migration in the two regionally separate populations were analyzed in relation to climatic variables, the results indicated that foremost a combined effect of growing season onset and the North Atlantic Oscillation influenced migratory timing, and only in individuals that had advanced migration. As growing season onset had advanced at both regions, but only elicited migratory change in southern willow warblers, it is proposed that intra-specific difference between populations prepare them differently to climate change. Willow warblers breeding at northern latitudes were also displaying absence of an otherwise common behaviour of the species: philopatry. It is suggested that the climate induced change in onset of the growing season, coupled with an increase in available territories, could have enabled a southern influx of dispersal-prone birds adopting a less philopatric breeding behaviour. Availability of territories was also studied in southern Sweden, in relation to 100 years of land use change and future climate change effects on forestry. The mass-conversion of grazed forest into coniferous sylvicultures that has occurred in Sweden 1900-2013 was shown to have negatively affected territory availability for willow warblers. The second most common bird species in Sweden, the chaffinch (Fringilla coelebs), was however shown to be largely unaffected. In a future scenario where rising temperatures will increase growth rates of trees, harvest rotation will be faster and both sylvicultures and logged areas will increase in coverage, favouring both species. Thus commonness in terms of landscape and species occurrence has altered historically and is dynamically linked. Historic perspectives were also applied to observations of spring arrival of 14 migratory bird species. A relative comparison of two data sets, collected over 140 years, revealed that short-distance migrants have changed their spring arrival more than long-distance migrants in southern Sweden. In conclusion, the results of this thesis provide insights into climate change effects on avian behaviour and ecology, document unique observations and contribute with a great spectrum of knowledge, from exact details on responses by individual birds, through long-term changes in populations to historical perspectives on shifts in entire landscapesAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.
15
Szulkin, Marta. "Inbreeding and its avoidance in a wild bird population." Thesis, University of Oxford, 2007. http://ora.ox.ac.uk/objects/uuid:25e95465-f4ab-43ce-92e2-9d7fe88efeef.
Full textAbstract:
Inbreeding occurs when relatives mate and have offspring. Inbreeding depression is hypothesized to have influenced the evolution of mating systems and behavioural mechanisms of inbreeding avoidance in the animal kingdom. Inbreeding in the wild is difficult to measure, as in order to build a pedigree allowing us to identify matings between relatives, the identity of as many as possible members of a population needs to be known. For a long time, the main source of knowledge about inbreeding depression was based on laboratory and agricultural studies, which did not reflect the array of environmental pressures wild populations have to cope with. In consequence, the deleterious consequences of inbreeding have often been underestimated. This is problematic because accurate estimates of the effect size of inbreeding depression are needed to study the strength of selection on inbreeding avoidance mechanisms, and are also of importance to conservation genetics. The aim of this thesis was to use pedigree data to infer the occurrence and effects of inbreeding using over forty years of breeding events of the great tit Parus major from Wytham Woods, Oxfordshire. The effects of inbreeding on fitness were investigated across a life-history continuum, and across environments. I found that close inbreeding (f=0.25) resulted in pronounced inbreeding depression, which acted independently on hatching success, fledging success, and recruitment success, and reduced the number of fledged grand-offspring by 55%. My results therefore suggest that estimates of fitness costs of inbreeding must focus on the entire life cycle. I also show that the variation in the strength of inbreeding depression varies across environments, particularly so the more the environmental variable considered is linked to fitness. These results emphasise the need of using relevant environmental contrasts when investigating inbreeding by environment interactions. I further asked whether individuals involved in matings with relatives differed relative to individuals mating with unrelated partners. I did not find any evidence for clear predictors of inbreeding, and I show that inbreeding depression in our population is entirely independent of any tendency for low quality parental genotypes, or phenotypes, to inbreed. Neither did I find any evidence for active inbreeding avoidance: great tits did not mate less often with kin than expected based on several scenarios of random mating, nor did I find increased rates of extra-pair paternity among birds breeding with relatives. In fact, I observed quite the contrary, as birds mating with kin exhibited a higher than average rate of close inbreeding relative to all scenarios of random mating investigated, showed lower rates of extra-pair paternity and divorce than birds mated to unrelated partners. I hypothesise that cases of occasional inbreeding in this population may result from mis-imprinting or a related process whereby some birds develop particularly strong bonds that are at odds with all predictions of avoiding inbreeding. Finally, I asked to what extent natal dispersal, a behaviour that is often hypothesized to play an important role in avoiding inbreeding, indeed reduces the likelihood of inbreeding. I found that male and female individuals breeding with a relative dispersed over several-fold shorter distances than those outbreeding. This led to a 3.4 fold increase (2.3-5, 95% CI) in the likelihood of close inbreeding relative to the population average when individuals dispersed less than 200m. This thesis demonstrates that inbreeding has deleterious effects on a wild population of birds, occurring throughout an individual’s life, and is of varying strength across environments. My findings strongly support the theory that natal dispersal should be considered as a mechanism of prime importance for inbreeding avoidance.
16
Saxton, Valerie Patricia. "Influence of ripening grape compounds on behavioural responses of birds." Phd thesis, Lincoln University. Agriculture and Life Sciences Division, 2004. http://theses.lincoln.ac.nz/public/adt-NZLIU20061207.121738/.
Full textAbstract:
Vineyards in New Zealand suffer bird damage caused by several avian species, including blackbirds and silvereyes. The introduced European Blackbird takes whole grapes which reduces yield. The self-introduced Australasian Silvereye pecks on grapes, leaving them on the vine to be further attacked by fungi and bacteria, and the subsequent off-odours can cause grapes to be refused by the winery or to suffer a price-reduction. Bird control methods remain primitive and largely ineffective during the long ripening period of wine grapes. An ecologically sound method to manage and reduce bird pressure requires deeper understanding of why some birds eat grapes, especially since grapes are not particularly nutritious.
This work investigated the extent to which blackbirds and silvereyes are attracted by various compounds in ripening grapes. Since in natural grapes these compounds develop and change simultaneously, I developed an artificial grape in which a single parameter could be investigated. Artificial grapes (and sometimes nectar) were presented on a bird feeder table and the responses of birds to hexose sugars, the aromas 2-3-isobutylmethoxypyrazine and geraniol, tartaric and malic acids, grape tannins, and purple and green colour were recorded on timelapse video and analysed.
17
Watkins, Nigel G. "Ecological correlates of bird damage in a Canterbury vineyard." Lincoln University, 1999. http://hdl.handle.net/10182/508.
Full textAbstract:
Birds are a major pest in vineyards both in New Zealand and overseas. There is a need for new behavioural research on birds' foraging habits and feeding preferences in vineyards, as much of the literature to date is anecdotal. Research on cues to birds' feeding will provide a basis on which new deterrent and control strategies can be devised. Spatial-and temporal bird damage in a small vineyard block was mapped to find if damage was correlated with grape maturity and environmental factors. Vineyard and field observations of bird behaviour using video technology combined with preference experiments aimed to establish the relative roles of grape sugar concentration and colour in avian selection. Proximity of vineyards to bird roosts affects damage levels, regardless of differing maturity between locations. The rate of damage tends to increase exponentially once grape maturity has passed a threshold of 13 °Brix. Bunches positioned closest to the ground receive more damage if blackbirds or song thrushes are the predominant pests. Both sugar concentration and grape colour were found to affect birds' feeding preference, but the importance of the two factors varied between years. Black and green grape varieties were differentially preferred by blackbirds (Turdus merula) and song thrushes (Turdus philomelos) while silvereyes (Zosterops lateralis) appeared to have no strong colour preference. It was apparent that there were other, not assessed, grape factors that also affect selection. In small unprotected vineyards that are adjacent to bird roosts the entire grape crop can be taken by bird pests. Besides removing the roosts, which can be beneficial shelterbelts in regions exposed to high winds, growers currently may have no alternative other than to use exclusion netting to keep crops intact. The differential preferences between bird species for variety characteristics suggest that any new deterrents and other strategies to deflect birds from grape crops may need to be species-specific.
18
Saxton, V. P. "Influence of ripening grape compounds on behavioural responses of birds." Diss., Lincoln University, 2004. http://hdl.handle.net/10182/28.
Full textAbstract:
Vineyards in New Zealand suffer bird damage caused by several avian species, including blackbirds and silvereyes. The introduced European Blackbird takes whole grapes which reduces yield. The self-introduced Australasian Silvereye pecks on grapes, leaving them on the vine to be further attacked by fungi and bacteria, and the subsequent off-odours can cause grapes to be refused by the winery or to suffer a price-reduction. Bird control methods remain primitive and largely ineffective during the long ripening period of wine grapes. An ecologically sound method to manage and reduce bird pressure requires deeper understanding of why some birds eat grapes, especially since grapes are not particularly nutritious. This work investigated the extent to which blackbirds and silvereyes are attracted by various compounds in ripening grapes. Since in natural grapes these compounds develop and change simultaneously, I developed an artificial grape in which a single parameter could be investigated. Artificial grapes (and sometimes nectar) were presented on a bird feeder table and the responses of birds to hexose sugars, the aromas 2-3-isobutylmethoxypyrazine and geraniol, tartaric and malic acids, grape tannins, and purple and green colour were recorded on timelapse video and analysed.
19
Tello, Ramos Maria Cristina. "The foraging behaviour of hummingbirds through space and time." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7402.
Full textAbstract:
Central place foragers, such as territorial hummingbirds, feed from resources that tend to be constant in space and to replenish with time (e.g. nectar in flowers). The ability to remember both where and when resources are available would allow these animals to forage efficiently. Animals that feed at multiple locations would also benefit from forming routes between these multiple locations. Hummingbirds are thought to forage by repeating the order in which they visit several locations following a route called a “trapline”, although there are no quantitative data describing this behaviour. As a first step to determining how and if wild free living hummingbirds forage by traplining, I decomposed this behaviour into some of its key components. Through five field experiments, where I trained free-living hummingbirds to feed from artificial flowers, I confirmed that territorial hummingbirds will, in fact, trapline. Birds will use the shortest routes to visit several locations and will prioritize those locations that are closest to a usual feeding site. Additionally, even though hummingbirds can learn to use temporal information when visiting several patches of flowers, the spatial location of those patches has a larger influence in how these birds forage in the wild. Since male and female hummingbirds were thought to forage differently I also tested whether there were sex differences in the types of cues they use when foraging. Contrary to expectation, female hummingbirds will also use spatial cues to relocate a rewarded site. Using the foraging ecology of rufous hummingbirds to formulate predictions as to what information these birds should use has lead me to discover that these birds forage in a completely different way than previously thought.
20
Ekblom, Robert. "Immunoecology of the Great Snipe (Gallinago media) : Mate Choice, MHC Variation, and Humoral Immunocompetence in a Lekking Bird." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4585.
Full text
21
Stader, Lulu D. "Breeding behaviour of a tropical bird : a study of the blue-throated Bee-eater (Merops viridis) using a relational database and DNA fingerprinting." Thesis, University of Stirling, 1994. http://hdl.handle.net/1893/11893.
Full textAbstract:
The breeding behaviour of the Blue-throated Bee-eater was studied at two colonies in Peninsula Malaysia during 3 breeding seasons, with particular emphasis on pair behaviour, mixed reproductive strategies and nestling competition. This is the first study of vertebrate social behaviour and ecology to contain the documentation of a relational database. This was designed to store and manipulate all data obtained from regular captures and biometric measurements of adults and nestlings and from observations of adults. DNA fingerprinting was used to establish the true genetic relationships between nestlings and their social parents: most nestlings were genetic offspring (72%). Nestlings were classified as illegitimate offspring using 95% confidence intervals of the band sharing coefficient and number of unexplained nestling bands as criteria. Very few if any nestlings were sired by an extra-pair male (fewer than 5%). Behavioural evidence of strong cooperation between pair members throughout the breeding season supports the DNA fingerprinting results of no confirmed case of offspring fathered by extra-pair males (extra-pair offspring; EPO). The Blue-throated Bee-eater probably has a near monogamous mating system. Most illegitimate nestlings had been 'dumped'. They were either the result of intra-specific nest parasitism (INP; 7%) or of 'quasi' parasitism (the offspring of the pair-male and an extra-pair female; 7-12%). INP by relatives of the hosts could have explained some intermediate band sharing coefficients. Anti-INP behaviour was demonstrated when experimentally 'dumped' eggs were almost always expelled before the onset of laying, but never afterwards. DNA fingerprinting showed that relatives may roost together and that related males may nest close together. Compared with other colonial Bee-eaters, M. viridis had low levels of helping-at-the-nest and EPO, but similar or higher levels of INP. The high nestling mortality in Blue-throated Bee-eaters was explained by a combination of three hypotheses, some of which were tested by experiment. (1) Insurance: extra-eggs are needed to counter hatch failure. (2) Brood reduction (including resource tracking): in times of food constraint, the laterhatched nestlings in asynchrously hatched broods starve. (3) Anti-INP hypothesis: these later-hatched nestlings are eliminated because they are likely to be illegitimate. Hatching failure was about 1 in 3 eggs overall. Help from the male allows an early onset of incubation which results in asynchronous hatching. Nestling hunger was shown to be a proximate factor affecting runt mortality both directly through competition and indirectly through nestling aggression. The demise of runts was delayed when conditions improved. Blue-throated Bee-eater broods are severely limited by food. Under this severe brood size constraint, breeding females may increase reproductive output by 'dumping' their last egg. This leads to the high frequency of INP observed in Blue-throated Bee-eaters. An early onset of incubation also gives the first-laid egg(s) a temporal developmental advantage over subsequently 'dumped' parasitic eggs. The 'dumped' nestlings are eliminated by starvation and siblicide, which may itself be an adaptation to INP to eliminate of unrelated nestlings.
22
Pople, Robert Grant. "The ecology and conservation of the white-winged nightjar Caprimulgus candicans." Thesis, University of Cambridge, 2003. https://www.repository.cam.ac.uk/handle/1810/225237.
Full textAbstract:
In the tradition of previous studies of threatened species, this thesis was undertaken with the aim of improving our understanding of the ecology of the White-winged Nightjar Caprimulgus candicans, and providing the information necessary to facilitate conservation efforts on its behalf. In 1998-2001, I studied a population of White-winged Nightjars at Aguará Ñu, an area of cerrado habitats within the Reserva Natural del Bosque Mbaracayù, eastern Paraguay. Over the course of three fieldwork seasons, I captured and ringed a total of 49 nightjars (34 adults and 15 young birds). Young females first bred at approximately one year old, while still in pre-definitive plumage. Young males exhibited a form of delayed plumage maturation, whereby they only attained definitive plumage following a prolonged moult spanning much of their first potential breeding season. No evidence was obtained to suggest that they succeeded in breeding while in this conspicuously intermediate state of moult. Considerable variation was noted in the plumage whiteness of definitive males, but no clear evidence was found for consistent age-related increases in white. During the breeding season, males defended small aggregated display territories, at which they conducted nuptial display flights between late August and early January. Female nightjars were responsible for all the parental care, and apparently visited male display arenas solely to obtain copulations. Chick paternity data confirmed that the study population was polygynous, with patterns of male aggregation suggestive of an exploded lek or 'landmark' mating system. Radio-telemetry studies showed that nightjars utilised home ranges of at least 20 to 40 hectares during the eight to ten months for which they were monitored. Home ranges contained a disproportionately large amount of young campo cerrado vegetation, but no forest or old campo cerrado habitats. When selecting foraging sites within their ranges, nightjars preferred younger and avoided older campo cerrado vegetation; wet grassland was utilised roughly in proportion to its availability. Observed patterns of habitat selection were potentially explained by the greater abundance of insect prey in younger habitats. When selecting daytime roost sites, nightjars preferred vegetation of intermediate age, reflecting their need for a balance between cover and ease of access. A more general analysis of patterns of sexual dimorphism within the Caprimulgidae showed that, although almost 80% of nightjar species exhibit some dimorphism of plumage whiteness, the study species was by far the most extreme case. The striking plumage of the male was partly explained by a strong positive relationship between wing white and openness of breeding habitats within the family. However, this failed to explain the complete absence of white in the female plumage, or the extent of white dimorphism shown by the species. The most likely explanation would appear to be that extreme plumage dimorphism occurred in conjunction with the evolution of polygyny and female-only care in this open-country species. The implications of these findings for the conservation of the White-winged Nightjar are highlighted, and recommendations are proposed for future work and conservation action.
23
Dalbosco, Dell'Aglio Denise. "Behavioural and ecological interactions between Heliconius butterflies, their predators and host plants." Thesis, University of Cambridge, 2016. https://www.repository.cam.ac.uk/handle/1810/267756.
Full textAbstract:
Heliconius butterflies exhibit Müllerian mimicry, in which two or more unpalatable species share a mutual advantage from having a common conspicuous colour pattern. These tropical butterflies have impressive visual signals, which are under conflicting selection pressures, as they are used in choosing potential mates and defending against visual predators through aposematic coloration. As both selection pressures are likely to be strong, different elements of the signal might be adapted for different receivers. Here, I combine sensory ecology with behavioural ecology to explain Heliconius colours signals of different co-mimic pairs. I explore how mimicry in Heliconius is perceived both from the perspective of predators and conspecifics, using visual abilities of both butterflies and birds. The different visual sensitivities of avian predators, H. erato females and males make them to perceive Heliconius coloration in different ways. My work suggests that having the ability to see in the ultra-violet light range enables higher discrimination between co-mimics both for birds and butterflies. Heliconius warning colours transmit a consistent signal across time of the day and habitat in a tropical forest for avian vision. In contrast through Heliconius vision there is evidence that patterns are more conspicuous in their own habitats. All these traits could facilitate communication between co-mimics and reduce the cost of confusion in courtship while still maintaining the advantages of Müllerian mimicry against predation. I conducted a field experiment to show that attack rates on a novel distasteful butterfly reduced over time, suggesting that Heliconius wing colouration can enhance aversion among predators. Finally, I have shown that Heliconius butterflies use leaf shape as a cue to approach their host plants, demonstrating the potential for Heliconius to drive negative frequency dependent selection on the leaf shape of their Passiflora host plants. Overall these results highlight ecological interactions between Heliconius butterflies, their predators and host plants.
24
Mann, Richard Philip. "Prediction of homing pigeon flight paths using Gaussian processes." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:bf6c3fb5-5208-4dfe-aa0a-6e6da45c0d87.
Full textAbstract:
Studies of avian navigation are making increasing use of miniature Global Positioning Satellite devices, to regularly record the position of birds in flight with high spatial and temporal resolution. I suggest a novel approach to analysing the data sets pro- duced in these experiments, focussing on studies of the domesticated homing pigeon (Columba Livia) in the local, familiar area. Using Gaussian processes and Bayesian inference as a mathematical foundation I develop and apply a statistical model to make quantitative predictions of homing pigeon flight paths. Using this model I show that pigeons, when released repeatedly from the same site, learn and follow a habitual route back to their home loft. The model reveals the rate of route learning and provides a quantitative estimate of the habitual route complete with associated spatio-temporal covariance. Furthermore I show that this habitual route is best described by a sequence of isolated waypoints rather than as a continuous path, and that these waypoints are preferentially found in certain terrain types, being especially rare within urban and forested environments. As a corollary I demonstrate an extension of the flight path model to simulate ex- periments where pigeons are released in pairs, and show that this can account for observed large scale patterns in such experiments based only on the individual birds’ previous behaviour in solo flights, making a successful quantitative prediction of the critical value associated with a non-linear behavioural transition.
25
Wolf, Isabelle Diana Felicitas Gudula Biological Earth & Environmental Sciences Faculty of Science UNSW. "Towards sustainable tourism in outback Australia: the behaviour and impact of nature-based tourists on vegetation and selected wildlife species." Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44572.
Full textAbstract:
Nature-based tourism offers significant socio-economic incentives to successfully replace more intrusive land uses but also causes negative environmental impacts. Currently, knowledge is needed about the effectiveness of specific management actions such as the provision of different access modes and tour experiences at minimizing these impacts while maximizing visitor satisfaction. Nature-based tourism activities were studied in the species-rich gorges of the Flinders Ranges in Outback Australia. This study developed a conceptual framework of visitor-environment relationships, constructed a regional visitor profile, assessed visitor monitoring methods to quantify usage intensity in relation to the access mode (roads vs. hiking trails), examined changes in vegetation and bird communities in relation to usage intensity and access mode, tested effects of approach behaviour among driving vs. hiking tourists on kangaroo behaviour, and designed a framework for a night-time wildlife tour. The usage intensity of gorge sections was best determined from visitor numbers stratified by their behaviour, as the access mode fundamentally changed visitor behaviour in gorges. High compared to low usage recreational tracks altered species community composition, decreased total plant cover, increased non-native species cover, increased or decreased plant diversity depending on the track distance, increased soil compaction, and decreased bird numbers and species richness. Vegetation changes had secondary aversive effects on the bird community. The magnitude and spatial extent of these community impacts were greater along roads than trails. Visitor approach towards kangaroos varied with the access mode and necessitated individual recommendations for low-impact behaviour. The optimal night-time observation tour employed night-vision devices and bat detectors and coupled visitor satisfaction with low impact on wildlife. A range of factors (e.g., weather conditions) moderated the susceptibility of the wildlife to tourism disturbance. To protect wildlife and habitat along recreational tracks in arid-lands gorges, it is recommended to (1) monitor usage intensity and the identified impact indicators within their effect zone, (2) curtail gorge usage by restricting vehicle access to sections and regulating high impact activities (e.g., wild camping), (3) base environmental education upon scientifically tested low-impact visitor behaviour, and (4) engage with tourism operators in the design of low-impact, yet satisfying tours based on scientific principles.
26
Seki, Yasuaki. "Structure and mechanical behavior of bird beaks." Diss., [La Jolla] : University of California, San Diego, 2009. http://wwwlib.umi.com/cr/ucsd/fullcit?p3355486.
Full textAbstract:
Thesis (Ph. D.)--University of California, San Diego, 2009.Title from first page of PDF file (viewed June 18, 2009). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 199-215).
27
Ross, Megan Reinertsen. "The effects of ultraviolet lighting on bird behavior." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/30066.
Full text
28
MCDONALD, DAVID BARTELLE. "MALE-MALE COOPERATION IN A NEOTROPICAL LEKKING BIRD (COSTA RICA)." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184173.
Full textAbstract:
Long-tailed Manakins Chiroxiphia linearis are frugivorous birds with a lek mating system and male-male cooperation in courtship display. I studied male-male networks and correlates of male mating success in a color-banded population in Monteverde, Costa Rica, from 1981 to 1986. Males were organized in teams at scattered perch-zones (75 to 300 m apart) that were usually in aural but not visual contact. Each team consisted of 3 to 15 males (x=7.1±3.4), in an apparent linear dominance hierarchy, with an alpha and beta male who did most of the courtship display. In a study population with 50 to 60 active males per season, only 6 to 8 males were alphas. Only betas inherited alpha status (n=3). Males appear to be 8 or more years of age before attaining beta status. Alpha tenure can last 4 years. Alpha males were rarely or never seen in zones other than their 'home' zone. Lower-ranking males maintained simultaneous affiliations with males at as many as 6 different zones. Each zone, therefore, was a sort of hub at which males with different affiliations around the rim came into contact. Each of the 6 major perch-zones shared at least one constituent with each of the other zones. The mean number of males shared by zones was 3.9 ± 2.7 (range=1 to 9). Marked changes occurred in male traits with increasing age and status. These included (1) Significant declines in weight throughout the lifespan, (2) a 4-year delay in plumage maturation with well-defined stages, (3) reduction in the number of zones with which males maintained affiliations, and (4) increasing probability of copulatory success (restricted to a small subset of the oldest males, ≥ 10 years of age). Variance in copulatory success was the highest yet described for birds. Of 85 males monitored between 1983 and 1986, copulations (n=121) were distributed among only 8 males. Four of these males accounted for over 90% of the copulations, with 63% accruing to one male. The beta male of this alpha copulated twice in the absence of his partner; all the other copulaters were alphas. I examined correlates of male mating success. Female visitation correlated with the number of unison 'toledo' calls given. If a female visited, copulatory success correlated both with a residual effect of the 'toledo' output and with the duration of the 'butterfly' component of the dual-male dance performance. My correlational results suggest that females do choose, on the basis of performance cues, among the small subset of males that are well-established alpha and beta partners. Development of alliances, as much as male combat, may determine attainment of high-performance partner status. Thus, sequential male-male interactions and female choice appear to produce nested subsets of successful males leading to an extreme in variance in male mating success. Males unsuccessful in male-male interactions are not 'eligible' for female choice. By requiring partnered display, females may be implicitly narrowing the subset of potentially successful males. In other lek systems the union, rather than the intersection, of the subsets produced by intra- and intersexual selection may include successful males. In that case, intrasexual selection via disruption of copulations may enlarge the pool of potentially successful males under intersexual selection and produce lower variances in male mating success. Students of sexual selection may need to consider the extent to which intra- and intersexual selection interact as union or intersecting sets to produce variance in male mating success.
29
Birn-Jeffrey, Aleksandra Victoria. "Scaling of running stability and limb posture with body size in galliform birds." Thesis, Royal Veterinary College (University of London), 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572447.
Full text
30
Godfrey, J. D. "Body-state dependent behaviour in birds." Thesis, University of Stirling, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297839.
Full text
31
Brighton, Caroline. "Attack strategies in birds of prey." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:4e8afdec-3b7b-43b1-a693-166d114c827f.
Full textAbstract:
Pursuit behaviours are vital in predator-prey interactions and in courtship for many flying animals. Existing research on target-directed flight behaviours in insects, birds and bats has aimed at identifying simple geometric rules describing the pursuit-flight trajectories. However, these geometric rules are only part of the picture as they only consider the outcome of the commanded changes in flight kinematics, and not the underlying guidance laws (dynamics) which generate these commands. To intercept a target, a pursuer implements a guidance law using sensory feedback to determine the required change in flight velocity, and the resulting kinematics determines the flight geometry. Most of the research until recently has examined insect flight systems, as the ethics of working with birds of prey are more complex and measuring their wide-ranging flight trajectories is difficult. Studies of predator-prey pursuit in birds have only described the geometrical rules for target interception, therefore overlooking the guidance laws which implement them. Therefore the aim of this thesis is to complete the picture by identifying the guidance laws used by birds of prey as they pursue and intercept targets both in the air and on the ground. I used onboard cameras and GPS to study attack flights in peregrine falcons (Falco peregrinus), and high-speed ground photogrammetry for attacks in Harris' hawks (Parabuteo unicinctus), to show that two different raptor species effectively implement the same guidance law of pure proportional navigation for intercepting manouevring and non-manouevring prey-targets. Proportional navigation is a feedback law whereby the bird's line-of-sight rate is fed back, in order to command a turn-rate in proportion to the change in line-of-sight rate, with a constant of proportionality N. Harris' hawks were found to use this guidance law in its simplest case with an N of approximately 1. This amounts to a pure pursuit course, meaning the bird maintains a heading angle of zero at all times (its velocity vector points at the target). Peregrine falcons were found to use a variety of values of N resulting in a quicker path to interception. A remarkable feature of most bird of prey eyes is that they possess two regions of high visual acuity - the shallow and deep foveae. The deep fovea is optimised for long-range vision, and is directed at approximately 45° to the side of the head. It has been proposed that the head is held in line with the body for streamlining, while the body is turned in flight to fixate the image of the prey on the deep fovea, resulting in a curved trajectory. My results contradict this theory, as falcons were seen to use saccadic head movements to maintain the image of the prey in their field of view whilst flying along curved trajectories - suggesting a different visual strategy. I provide the first quantitative analysis of how birds are able to guide their flight for successful prey capture. Not only does this provide new insights into animal behaviour and evolution, but this research has many applications in engineering, where there is a wide and growing interest in vision-based approaches to guidance and control in both civil and military spheres.
32
Haller, Karon Anne. "The double bind : paradox in human behavior /." Access Digital Full Text version, 1989. http://pocketknowledge.tc.columbia.edu/home.php/bybib/1085793x.
Full text
33
Jiang, Yiting. "Anti-predator Behavior of Birds and Conservation." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS076/document.
Full textAbstract:
Prey s'appuie sur les décisions d'évasion lorsqu'il est confronté à des prédateurs pour maximiser les avantages de rester en place tout en réduisant les coûts de la prédation. Ce compromis de l'histoire de vie peut être reflété par la distance d'initiation de vol (FID), la distance à laquelle un individu prend son envol lorsqu'il est approché par un humain. J'ai abordé les facteurs potentiels expliquant la variation FID avec des données d'espèces d'oiseaux en Europe. La variabilité génétique était liée au risque de prédation FID; les espèces d'oiseaux menacées avaient généralement une FID plus longue que les espèces proches non menacées; le caractère distinctif de l'évolution (ED), un indicateur reflétant l'isolement phylogénétique des taxons, était positivement lié à la FID chez les oiseaux d'eau; La FID moyenne de différentes espèces d'oiseaux était positivement corrélée avec les niveaux spécifiques de MDA (malondialdéhyde qui est un indice de stress oxydatif) et UA (acide urique, qui est une mesure de la capacité antioxydante) et FID augmentée avec la taille du troupeau chez les espèces grégaires mais pas chez les espèces non grégaires. Ces résultats peuvent contribuer à la compréhension des causes et des conséquences des différences interspécifiques dans le comportement de fuite des prédateurs contre les prédateurs, et, plus important encore, ils peuvent fournir des moyens de résoudre les problèmes de conservation. Mots-clés : masse corporelle, taille du cerveau, taille effective de la population, modèle linéaire phylogénétique, stress oxydatif, comportement socialPrey rely on escape decisions when confronted with predators to maximize the benefits of staying put while reducing the costs of predation. This life history compromise can be reflected by flight initiation distance (FID), the distance at which an individual takes flight when approached by a human. I addressed potential factors explaining variation FID with data from bird species in Europe. Genetic variability was related to predation risk FID; threatened bird species generally had a longer FID than non-threatened closely related species; evolutionary distinctiveness (ED), an indicator reflecting the phylogenetic isolation of taxa, was positively related to FID in waterbirds; mean FID of different species of birds was positively correlated with species-specific levels of MDA (malondialdehyde which is an index of oxidative stress) and UA (uric acid, which is a metric of antioxidant capacity) and FID increased with flock size in gregarious species but not in non-gregarious species. These findings may contribute to the understanding of the causes and consequences of interspecific differences in anti-predator escape behavior of birds, and, more importantly they may provide means for resolving conservation problems. Key words: body mass, brain size, effective population size, phylogenetic linear model, oxidative stress, social behavior
34
Rands, Sean Alexander. "Dynamic reserve allocation in breeding birds." Thesis, University of Bristol, 2000. http://hdl.handle.net/1983/ec222c2b-4d29-4abf-8cc8-10dab9584007.
Full text
35
Baker, David J. "The foraging behaviour of granivorous birds : a mechanistic perspective." Thesis, Bournemouth University, 2010. http://eprints.bournemouth.ac.uk/17301/.
Full textAbstract:
1. The functional response, i.e. the feeding rate as a function of prey density, links resource availability to population level demographic rates. The functional response is often central to behavioural-based population models that predict the effect of environmental changes on populations based on the assumption that each individual tries to maximise its fitness at all times. 2. The functional response is a well studied phenomenon for some groups of foragers and many mechanistic models of the functional response have been derived to account for variations in foraging behaviour. However, only a few functional response models have been applied to granivorous farmland birds and these models often have simplifying assumptions that are likely to be inappropriate for these foragers. Consequently, the functional response models that often lie at the core of behavioural-based population models are untested and quite possibly provide a poor prediction of the functional response. 3. The objectives of this thesis are to: (i) test the ability of functional response models to predict the functional response of granivorous birds; (ii) identify incorrect assumptions in these models; and (iii) derive new functional response models that better describe the observed behaviour of these foragers. 4. Here I have found that many of the underlying assumptions of simple functional response models are inappropriate for granivorous birds and several new mechanistic models have been derived that attempt to describe the behaviour more accurately. Vigilance was shown to frequently interact with incompatible behavioural processes (i.e. searching) and affect the feeding rate at low prey densities. Handling time was divided into two components (i.e. attack and process) and a simple mechanistic model was derived to predict the attack component of prey handling. The searching mode of granivorous birds was shown to be akin to a pause-travel forager at low prey densities and, lastly, habitat structure was shown to reduce the feeding rate by restricting the searching area. 5. These finding will help in the development of more biologically 'realistic' functional response models and provide a more accurate prediction of the functional response when used to predict the effect of environmental change on the intake rate of foragers. z
36
Troisi, Camille A. "An investigation of teaching behaviour in primates and birds." Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12008.
Full textAbstract:
Many animals socially learn, but very few do so through teaching, where an individual modifies its behaviour in order to facilitate learning for another individual. Teaching behaviour is costly, but can confer numerous advantages, such as high fidelity transmission of information or an increase in the rate of social learning. In many putative cases of teaching, it is not known whether the pupil learns from the modified behaviour. This thesis addresses this issue in three cases of potential teaching behaviour. In particular, it investigates whether the role of food transfers in wild golden lion tamarins is to teach which foods are good to eat (Chapter 5). There was little evidence that novel foods were transferred more than familiar foods, and this was not due to the juveniles attempting to obtain novel foods more than familiar ones, or by adults discarding novel foods more than familiar ones. Transfers were however more successful when donors had previously ingested the food type transferred. Successful food transfers also had a positive correlation with foraging choices once juveniles were older, suggesting they learned from food transfers. In golden lion tamarins, this thesis also examined whether juveniles learned from food-offering calls which substrates were good to forage on (Chapter 6). Juveniles that experienced playback of food-offering calls ate more on a novel substrate, than juveniles that did not experience those playbacks, both immediately as the calls were being played, and in the long term, six months after the playbacks. This suggests that juveniles learned from the playbacks. Finally, this thesis attempted to replicate previous findings showing that hens modify their behaviour when chicks feed from seemingly unpalatable food, and explored whether chicks learned what food to eat based on the maternal display (Chapter 7). The experiment failed to find evidence for teaching behaviour, but results were not inconsistent with previous findings. Moreover, there was little evidence that chicks learned from their mother, quite to the contrary, hens seemed to acquire their foraging decisions based on their chicks' choices.
37
Beauchamp, Guy. "Transfer of information about distant foods in birds." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63778.
Full text
38
Pattinson, Nicholas Bruce. "Seasonal physiological and behavioural responses of a small bird in a hot, arid habitat." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/19728.
Full textAbstract:
The role that climate plays in the ecology of organisms is perhaps the most pronounced where the earth’s environments are most extreme. In arid-zones, organisms have to deal with large seasonal shifts and/or extremes in temperature and/or moisture levels. As a result, arid-zone species are sensitive to climatic changes. I assessed the physiological and behavioural adjustments of an arid-zone endemic passerine, the rufous-eared warbler (Malcorus pectoralis), to seasonal changes in the Karoo semi-desert of South Africa. Respirometry measurements in the field showed that the warblers’ basal metabolic rate was lower and set point body temperature (Tb) was higher in summer compared to winter. At high air temperatures (Ta) evaporative water loss (EWL) rate was significantly lower in summer compared to winter, while Tb showed a clear pattern of heterothermy that was similar in both seasons. Compared to winter, the warblers in summer were able to remain calm, and tolerate higher Ta’s, before their Tb’s increased to potentially detrimental levels. Behavioural observations showed that free-living warblers exhibited significant temperature-dependence in their behaviour; they increased panting behaviour, and reduced activity levels, time spent preening, and foraging effort at high Ta’s in summer. The warblers also displayed a considerable decrease in foraging success, and a shift in microsite use, at high Ta’s in summer. I hypothesise that the flexible responses the rufous-eared warblers show are aimed at increasing their heat tolerance in summer, and help them balance their energy and water demands in an arid environment that exhibits wide seasonality in Ta, in addition to high summer Ta. My findings emphasise the importance of identifying, as well as understanding, the associated costs of physiological and behavioural responses to environmental variables. This information is valuable in terms of predicting biologically meaningful responses (and hence, vulnerability) of arid-zone avian communities to climactic shifts.
39
Elliott, Kyle Hamish. "How can birds live long and hard? patterns in the physiology and behaviour of aging birds." Company of Biologists, 2013. http://hdl.handle.net/1993/22283.
Full textAbstract:
As animals age, they are expected to invest successively more energy in reproduction as they have fewer subsequent chances to reproduce (the “restraint” hypothesis). Conversely, the oldest animals may show restraint in reproduction because even a small increase in energy expended during reproduction may lead to death. Alternatively, both young and very old animals may lack the ability to maintain high levels of energy expenditure (the “constraint” hypothesis), leading to reduced reproductive success. Many studies have observed an increase in reproductive success with age followed by a reduction at the end of life, but fewer studies have examined the proximate mechanisms, which provide a context for understanding ultimate causes. I examined over 30 behavioural and physiological metrics of aging in two species of free-living long-lived seabirds (thick-billed murres Uria lomvia and black-legged kittiwakes Rissa tridactyla) and a short-lived passerine (tree swallows Tachycineta bicolor). For all species, reproductive success was high at intermediate ages. In support of the “restraint” hypothesis, when birds were stressed glucocorticoid hormones, which direct energy away from reproduction and towards survival, were higher in young birds (swallows) and both young and very old birds (kittiwakes and murres). When birds were handicapped older birds expended more energy. When challenged exogenously, there was no change in hormone levels with age, implying that they were “choosing” to be restrained. Resting metabolic rate (RMR) declined linearly with age in both seabird species. T3, which I show is indicative of RMR in birds, also declined with age, demonstrating that the reduction in metabolism was strategic and not due to changing body composition. In contrast, daily energy expenditure in both seabird species during breeding was constant with age while antioxidant capacity became elevated during middle age, and further increased with age. Several measures of behavioural performance did not vary with age. I conclude that hormonal cues lead to greater investment in adult’s energy stores over its offspring’s energy reserves (restraint hypothesis) at the start of life. At the end of life, both hypotheses were supported; energy expenditure was constrained by senescence, leading to increased restraint in investing additionally in offspring.
40
Morand-Ferron, Julie. "Foraging innovations and kleptoparasitism in birds." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=102814.
Full textAbstract:
The ability to invent new solutions to old or novel problems is often equated with intelligence, both in humans and non-human animals. Behavioural flexibility can be defined operationally by looking at the frequency of novel or unusual behaviours, i.e. innovations, in different taxa. Despite the potential survival benefits of behavioural flexibility in the face of changing conditions, there is variation among taxa in the propensity to innovate. Here, I examine in detail one foraging innovation, dunking behaviour (the immersion of food items in water) in Carib grackles (Quiscalus lugubris) of Barbados. I show that the rarity of dunking behaviour in the field is not due to the inability of most individuals to learn and/or perform it, but rather to the balance of costs and benefits not being favourable to its expression in most field conditions. In this population, dunking functions as a proto-tool food-processing technique speeding the ingestion of items that are difficult to swallow. The frequency of the behaviour depends on food characteristics, travel costs between the food source and water, and the probability of losing items to conspecifics. Dunking renders grackles vulnerable to food theft because it involves releasing food items in water, where there is often a build-up of conspecifics. When faced with a high risk of kleptoparasitism, grackles reduce the frequency of dunking, engage in aggressive displays, and keep items in the bill while dunking. Kleptoparasitism not only reduces the rate of dunking by increasing costs to the behaviour, but also by constituting an alternative foraging tactic. The payoffs to this tactic are frequency-dependent; i.e. they decrease as the frequency of kleptoparasites increases in the group. A comparative study on ecological, morphological and behavioural predictors of the occurrence of kleptoparasitic tactics among bird families point to an important role of predation and cognitive abilities in favouring the evolution of kleptoparasitism. Thus, avian food-stealing should not be regarded as a "cognitively simpler" alternative to intelligent behaviour, but as another form of behavioural flexibility. Large-brained primates and birds share the ability to learn quickly, innovate, use tools and engage in exploitative tactics, suggesting that these abilities have not been traded-off against each other, but have instead evolved together.
41
Kapuscinsky, Hatch Karen. "Acquisition of foraging skills in juvenile ringdoves : who do they learn from?" Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61178.
Full textAbstract:
This thesis seeks to determine if juvenile birds preferentially select foraging information from their parents, by examining the acquisition of novel food-finding skills in juveniles of a flock-feeding species, the ringdove (Streptopelia risoria).The first experimental examined the flock feeding behaviour of juvenile ringdoves foraging in a small aviary flock composed of kin and non-kin; frequencies of local enhancement, food begging and aggression were recorded, as well as the individuals that the juvenile associated with while searching for food. Juvenile ringdoves foraged significantly more often with their kin and were aggressed more by non-kin. The last three experiments tested juveniles on three components of foraging: novel food type, environmental colour cues associated with food and novel food-searching techniques. All three involved a choice-test where the juveniles had their father and an unrelated flock member as demonstrators. All three choice-tests showed there was no preference for selecting either demonstrator's solution. Juvenile doves in the field may appear to learn from their parents simply because they associate more with them. (Abstract shortened by UMI.)
42
Spencer, Karen. "Reproductive effort strategies in passerine birds : the role of body state." Thesis, University of Stirling, 2000. http://hdl.handle.net/1893/21847.
Full textAbstract:
State-dependent life history theory predicts a trade-off between an individual's state and reproductive effort. The identification and effects of key state variables, however, have not been explored empirically in depth. Although there are some studies which have provided evidence that state-dependent behaviour indeed occurs, the bulk of this work is neither experimental, nor related to reproduction. Furthermore, the quantitative effects of manipulations of specific state variables are invariably unknown (McNamara & Houston 1996). This thesis explores potential trade-offs between state and behaviour and determines if energy reserves can be employed as a useful state variable. In contrast to other empirical studies, parental states (energy reserve at dawn) were experimentally manipulated using a direct method, namely changes in overnight temperature (Warming, Chilling and Control). The effects of these temperature changes were quantified using indirect calorimetry. Responses to these experimental manipulations were measured by behavioural observations, a common method in behavioural ecology, but were also quantified in terms of energy expenditure, with the aid of the doubly labelled water technique. Thus, this thesis provides a unique quantitative approach, in that it measures both manipulations and responses in the currency of energy. Individual energy reserves at dawn significantly affected resource allocation decisions the subsequent day. Birds with surplus energy upon release increased the number of feeding visits to their nestlings whilst in parallel increasing energy expenditure. Those with an energy deficit at dawn, conversely decreased nest visitation rates along with energy expenditure. There were no effects of temperature manipulations upon mass or fatscore changes over the trial period, suggesting a regulation of somatic investment at a threshold level, whilst reproductive effort was varied depending on parental state. The responses to positive manipulations (warming) were congruent across two species with differing foraging ecologies: the swallow, an aerial feeder foraging in a variable environment; and the great tit, foraging in relatively stable woodland. Thus, the behavioural and energetic responses seen here were not the result of species-specific strategies. This points the way towards a general rule within state-dependent behaviour. The trade-off identified here implies that reproduction carries a cost, and that reproductive effort will be reduced if an animal's survival is jeopardized and vice versa: a life history response, mediated by an individual's body-state. Furthermore, the response of birds to positive and negative manipulations was large enough to be readily detected, even amongst the considerable variation in energy expenditure related to individual differences. This suggests that body-state not only plays a key role in allocation decisions, but that it is comparable in the scale of its effects to other major influences on energy expenditure of free-living animals.
43
Woodin, Melanie A. "Circadian organization of diving behaviour and respiratory chemoreflexes in birds." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0016/MQ29360.pdf.
Full text
44
Shoji, Akiko. "At-sea behaviour in marine birds : a life-history perspective." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:01c92d20-9059-4c47-ba2a-cb313d6f05e7.
Full textAbstract:
Recent bio-logging technology and associated techniques have uncovered the distribution, behaviour, and phenology of marine predators at remote locations, providing us with insights of not only scientific merit, but also in terms of conservation and management. This thesis explores the at-sea behaviour of marine birds using field studies and ethoinformatic approaches by using multiple data loggers, focusing on four species of free-ranging seabirds breeding in the UK. Key findings and conclusions are: Extending travel distance in central place foragers in the wild is associated with higher prey quality as estimated by an indirect method based on dive profiles. This result is consistent with a prediction of optimal foraging theory, but my results show empirically that seabirds are able to increase reward with distance at the extended scale of the marine environment. Razorbills Alca torda are capable of adjusting their foraging behaviour in response to proximate environmental conditions. The potential mechanisms underlying this adaptive behaviour are independent of breeding stage, but the magnitude of flight orientation is scale-dependent. These results suggest that Razorbills are capable of optimising their foraging adaptively, possibly reading cues from the environment or conspecifics. Diving behaviour in sympatric Atlantic Puffins Fratercula arctica and Razorbills is very similar, in contrast to the predictions of the competitive exclusion principle. They are likely to be near carrying capacity for the location and this may explain why Skomer’s Razorbill population is declining while its puffin population is stable. Differences in foraging trip duration of chick-rearing Manx Shearwaters Puffinus puffinus reflect differences in resource allocation between provisioning offspring and self-feeding. I developed a model based on patch quality and travel time to show that birds should use bimodal foraging trip durations to optimise feeding rates for their offspring. Individual reproductive performance in Manx Shearwaters can be predicted from previous breeding phenology and is linked to differences in overwintering behaviour patterns. This carry-over effect reveals the existence of a trade-off between current parental investment and future reproductive performance.
45
Nicolakakis, Nektaria. "Innovation rate, brain size and species richness in birds." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31280.
Full textAbstract:
The number of species varies greatly among taxa. In birds, for example, the parvorder Passerida contains 3556 species while the Odontophorida (New World Quails) contains only six species. This uneven distribution of species among avian taxa is not random and therefore warrants an explanation. The behavioral drive hypothesis stipulates that the capacity for innovation, coupled with the rapid transmission of the behavioral novelty to conspecifics, may expose individuals to new selective pressures and help fix mutations that would otherwise not be expressed. This should lead to accelerated rates of evolution. I test this hypothesis by examining the link between behavioral flexibility and the number of species per taxon. I adopt a comparative approach and seek a general explanation of richness, thereby removing the traditional focus placed on the success of the songbirds and on their complex singing apparatus. I use two measures of flexibility, feeding innovation rate and relative brain size. (Abstract shortened by UMI.)
46
Johnstone, I. G. "Space use by passerine birds : a study of territory economics in robins Erithacus rubecula and dippers Cinclus cinclus." Thesis, University of Stirling, 1994. http://hdl.handle.net/1893/2611.
Full textAbstract:
1. Cost constraints in models of territory size are based on time/activity/laboratory estimates that predict birds using larger territories will incur higher energy costs. The predicted form of the cost constraint may be linear, accelerating or decelerating depending on assumptions inherent in the models. The aim of this study was to assess the reality and form of the cost constraint by making direct measurements of the energy costs of territory use in birds that occupy territories of different size and shape; polygonal territories represented by the robin Erithacus rubecula, and linear by the dipper Cinclus cinclus. Free-living energy expenditure was measured using the doubly-labelled water technique, whilst simultaneously recording patterns of territory use by radio-tracking. 2. Territorial robins concentrated their activity in one or more foraging patches located in bushes. Range polygons containing all the foraging patches used by an individual provided estimates of territory area, and were generally of high eccentricity. A small proportion of robins was classified as non-territorial based on range polygon areas. Furthermore, while territorial robins showed high fidelity to ranges over the short term (days), non-territorial individuals were nomadic. Over the longer term (months), however, some territorial robins showed range drift. Dippers similarly used preferred core regions within ranges, although there was no selection for particular habitat features. 3. Because robins occupied territory polygons which varied from polygonal to highly linear, work was focused on this species to allow intra-specific comparison. Robins tended to commute between foraging patches by flying. It was appropriate, therefore, to describe territories in terms of a number of patches linked by a network of flight paths. This generated two further measures of territory size; the number of patches used and the total flight distance between patches. 4. The robins exploited a renewing food supply. Predictions were tested concerning the temporal scheduling of visits to foraging patches within territories. Patches tended to be separated by flight paths of similar lengths, and were visited in a regular sequence. Although the number of foraging patches used varied, all territories had similar total core areas. Robins using many small foraging patches commuted between patches more often and covered a larger total flight distance during each foraging circuit of the territory. The configurations of foraging patches were used in a highly linear manner. This was true even if the territory containing them was of low eccentricity. 5. Changes in structure and pattern of use varied predictably with territory size, and could be described mathematically. Based on this and published time/activity budgets, a suite of models was developed to predict how energy costs would vary with number of patches used and total flight distance between patches. Models were tested by directly measuring the energy expenditure of robins using different territories. The number of patches used and total flight distance between patches were both significantly correlated with energy expenditure, while territory area was not. One of the models showed a significant fit to the observed data, and suggested that the form of the energy cost constraint on territory size was linear. The effect of territory shape on energy costs was minimal. The implications of these results for models of territory size are discussed. 6. The slope and elevation of the energy cost constraint varied with the morphology of territory occupants. Based on this, an association of morphology with territory size was predicted; robins of lower mass and wing-loading using larger territories. The observed data supported these predictions, and suggested a possible genetic predisposition to particular patterns of territory occupancy in the robin.
47
Catry, Paulo X. "Ecology and behaviour of Great Skuas breeding on Foula (Shetland)." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388551.
Full text
48
Wink, Judy. "Great horned owl nestling behavior /." Instructions for remote access. Click here to access this electronic resource. Access available to Kutztown University faculty, staff, and students only, 1985. http://www.kutztown.edu/library/services/remote_access.asp.
Full textAbstract:
Thesis (M.S.)--Kutztown University of Pennsylvania, 1985.Source: Masters Abstracts International, Volume: 45-06, page: 3047. Typescript. Abstract precedes thesis as preliminary leaves [1-2] Includes bibliographical references (leaves 64-66).
49
McKean, Laurie Moore 1955. "Foraging efficiency and cultural transmission of information between Gray-breasted Jay flock members." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276909.
Full textAbstract:
In this thesis I discuss (1) the importance of status-age variations in the foraging behavior of individuals within a flock and (2) cultural transmission of foraging information among Gray-breasted Jays (Aphelocoma ultramarina), a cooperative breeder. Results of the experiments suggest that (1) subordinates are less successful in certain foraging situations than dominants, (2) the foraging preferences of young birds are not as defined as those of adults, (3) subadults obtain foraging information from adult flock members, and (4) older subordinates may not change their established preferences as easily as dominants (or younger birds) even when a cost to that preference is introduced. I suggest that, at least in this cooperative breeder, the flock provides a valuable source of environmental information.
50
Johansson, Malin. ""Wrist-cutters" : En explorativ studie över socionomstudenters bild av en person med självskadebeteende och den följande problematiken." Thesis, Linnéuniversitetet, Institutionen för socialt arbete, SA, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-21769.
Full textAbstract:
The purpose of this study is to analyse and describe social work students’ view on a person with self-injurious behaviour and the following issues. The aim and focus is on the general depiction. The theoretical perspectives have been intersectionality and its focus on social constructivism, and gender perspectives. The method was semi-structured interviews with eight social work students at Linnaeus University Kalmar. The collected data was the social work students’ opinions and it was contrasted with the previous research and was analysed from the above perspectives. The main conclusion is that social work students’ view on a person with self-injurious behaviour generally not consistent with the previous research. Previous research says that a person with self-injurious behaviour generally is a young, blonde, normal female. The majority of the social work students say that a person with self-injurious behaviour is a depressed, young female with dark hair and dark clothes. The social work students focus more on why a person goes to such extremes and hurts themselves.