The migration strategy, diet and foraging ecology of a small seabird in a changing environment

This thesis examines the migration strategy, diet and foraging ecology of the smallest Atlantic seabird, the European Storm Petrel Hydrobates pelagicus.Evidence was found for sex-specific migration behaviour, opportunistic feeding, temporal variation in diet, and the strategy regulation of energy reserves in response to varying environmental conditions, as a buffer against starvation during migration. Molecular sexing from feather and faecal samples revealed an unexpectedly strong female bias in the sex ratio of Storm Petrels attracted to tape-lures of conspecific calls, during their northwards migration past the coast of SW Portugal. The thesis describes the development and application of molecular techniques, in combination with stable isotope analysis, to study Storm Petrel diet by the detection of prey DNA from faecal samples. The major category of prey detected was fish (chiefly European Sardines Sardina pilchardus). Other components of the diet were other pelagic and demersal fish species, Cephalopoda (primarily cuttlefish Sepia spp.), Amphipoda, Isopoda and a range of terrestrial invertebrates. Large between-year fluctuations in the level of body reserves carried by these birds were observed over the 21-year study period (1990-2010). The pattern of body mass variation followed a smooth oscillation, which was not an artefact of differences among years in the distribution of capture effort, body size or sex ratio changes. Local sea surface temperature (SST), net primary production (NPP) and European Sardine biomass were key factors associated with between-year changes in Storm Petrol body reserves. These associations suggest that Storm Petrels strategically regulate their body reserves to buffer against starvation in years of low food abundance.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The migration strategy, diet and foraging ecology of a small seabird in a changing environment

This thesis examines the migration strategy, diet and foraging ecology of the smallest Atlantic seabird, the European Storm Petrel Hydrobates pelagicus.Evidence was found for sex-specific migration behaviour, opportunistic feeding, temporal variation in diet, and the strategy regulation of energy reserves in response to varying environmental conditions, as a buffer against starvation during migration. Molecular sexing from feather and faecal samples revealed an unexpectedly strong female bias in the sex ratio of Storm Petrels attracted to tape-lures of conspecific calls, during their northwards migration past the coast of SW Portugal. The thesis describes the development and application of molecular techniques, in combination with stable isotope analysis, to study Storm Petrel diet by the detection of prey DNA from faecal samples. The major category of prey detected was fish (chiefly European Sardines Sardina pilchardus). Other components of the diet were other pelagic and demersal fish species, Cephalopoda (primarily cuttlefish Sepia spp.), Amphipoda, Isopoda and a range of terrestrial invertebrates. Large between-year fluctuations in the level of body reserves carried by these birds were observed over the 21-year study period (1990-2010). The pattern of body mass variation followed a smooth oscillation, which was not an artefact of differences among years in the distribution of capture effort, body size or sex ratio changes. Local sea surface temperature (SST), net primary production (NPP) and European Sardine biomass were key factors associated with between-year changes in Storm Petrol body reserves. These associations suggest that Storm Petrels strategically regulate their body reserves to buffer against starvation in years of low food abundance

The effect of maternal smoking and alcohol consumption on lip morphology

Objective: To determine whether maternal smoking and/or alcohol consumption has an influence on lip morphology. Maternal smoking is a known risk factor for orofacial clefts; however, its influence on normal lip variation is unknown. Recent research regarding normal lip morphology has been contradictory. Design: Retrospective cohort study. Setting and participants: A total of 4747 children from the Avon Longitudinal Study of Parents and Children (ALSPAC) who each had 3D facial scans carried out at 15 years of age were included in the study. Methods: Each of the participants was automatically categorised regarding predetermined lip morphological traits. Questionnaires completed by their mothers identified smoking and alcohol habits during pregnancy. Logistic regression analyses were applied to determine the effect of maternal smoking and alcohol consumption on lip morphology. Results: Maternal smoking has significant effects on upper and lower lip contours, Cupid’s bow, lower lip-chin shape and lower lip tone (all P 6 units of alcohol are consumed per week (P = 0.0149, 32 weeks). Overall results suggest a deeply grooved philtrum is more likely if alcohol is consumed. Investigating the combined effect of smoking and alcohol consumption, lower lip contour (P = 0.00923) and lower lip-chin shape (P = 0.0171) are statistically significant, with lower lip contour more likely to be narrow in the midline, and lower lip-chin shape more likely to be an angular concavity. Conclusion: Maternal smoking influences a number of lip traits, including a possible epigenetic effect on upper lip contour. Maternal alcohol consumption, particularly at a high level, influences philtrum shape. Maternal smoking and alcohol consumption have a combined effect on lower lip contour and lower lip-chin shape

Applying an automated method of classifying lip morphological traits

Objective: To apply an automated computerised method to categorise and determine the prevalence of different types of lip traits, and to explore associations between lip traits and sex differences. Design: Observational descriptive study utilising an automated method of facial assessment. Setting and participants: A total of 4747 children from the Avon Longitudinal Study of Parents and Children (ALSPAC) who each had 3D facial scans carried out at 15 years of age. Methods: Each of the participants was automatically categorised regarding predetermined lip morphological traits. Descriptive statistics were applied to report the prevalence of the different types of each trait, and chi-square tests were used to investigate sex differences and associations between traits. Results: A total of 4730 individuals were assessed (47% male, 53% female). Eight predetermined lip traits have been reported previously. There were differences in prevalence for all lip traits in male and female patients (all P ⩽ 0.0002), with differences between the sexes described for each trait. For example, a deeply grooved philtrum of average width was more prevalent in boys, and an indentation near the upper vermilion border was more prevalent in girls. Each of the traits was significantly associated with the other traits (all P < 0.0001), with particularly strong associations seen between traits in the same region (e.g. upper lip). Individual associations between traits are reported; for example, a straight lip contour was found to be associated with no true vermilion border in both the upper and lower lip regions. Conclusion: The automated computerised method described is an invaluable tool for the categorisation of lip morphological traits. The prevalence of various types of traits has been described. Sexual dimorphism exists for all the lip traits assessed. Generally, each of the traits are associated with all other traits, with individual associations reported

Influence of environmental factors and energetic value of food on Little Tern Sterna albifrons chick growth and food delivery: Capsule Chick diet and early growth parameters differed between birds breeding on natural (sandy beaches) and alternative (salinas) habitats

Aims To describe diet and growth of Little Tern chicks, to examine the influence of tide and wind speed on food delivered to chicks in southern Portugal, and to determine whether diet and early chick growth parameters differed between birds breeding in natural (sandy beaches) and man-made alternative (salinas) habitats. Methods Nests were marked and visited regularly. Chicks were ringed and weighed at hatching. Between 12 and 14 nests were enclosed by a fence in order to measure and weigh chicks every day. Prey items delivered to fenced chicks were observed daily from hides, in different tidal periods and wind speed conditions. Prey items dropped in the colonies were collected. Foraging efficiency of adults was evaluated in relation to tide and wind speed. Fresh prey items were collected to determine their energetic content using a calorimeter. Results A chicks grew faster than B chicks, but both attained the same weight, tarsus-length and wing-length at 19 days old; C chicks attained the same values at day 21. There were significant differences in early growth parameters. A and B chicks grew faster on sandy beaches than on salinas. The main prey items were Atherina spp., Fundulus sp. and shrimps in salinas and Sardina pilchardus, Atherina spp. and Belone belone on sandy beaches. There was no correlation between ingestion rate and chick age, but mean length of prey ingested by chicks increased significantly with age. Conclusion Tide and wind speed influenced both size and type of prey delivered to chicks. Parents met the increasing energy demands of the growing chicks by adjusting prey size rather than prey delivery frequency. Differences in chick growth between salinas and sandy beaches could be related to both parental quality and diet. The presence of a high energy-content euryhaline fish species in the salinas, together with more sheltered conditions and no tidal influences, may be important in explaining the use of salinas by Little Terns