Menstrual status and thermoregulatory responses of active adolescents during exercise in a cold environment

This study examined the interactions between the reproductive status and the thermoregulatory responses during exercise in the cold in girls involved in competitive sports. Four girls with established menstrual cycles comprised the eumenorrheic menarcheal group (EM) and 5 non-menstruating girls comprised the pre-menarcheal group (PM). During the first visit maximal oxygen consumption, height, weight and percent body fat (%BF) were measured. The second visit involved: a determination of metabolic rate in thermoneutrality (21°C) involving 10-min rest and 20-min cycling (30% of VCL max), and a cold stress test (5°C, 40% humidity, <0.3 m/s air velocity) involving 20-min rest and 40-min cycling (30% of VCL max.). Subjects in the EM group were tested twice in the chamber during the follicular and luteal phases. Pre-menarcheal subjects were found to have significantly (p<0.05) lower core temperatures during the final stages of cold exposure. Overall, body fat was not significantly correlated with core temperature in the cold, however there was a significant surface-to-mass ratio difference between the groups. While in the follicular phase, EM girls had a higher core temperature during cold exposure. Therefore, reproductive hormonal status seems to be an important factor in terms of cold tolerance in females during adolescence.

Perceptions of some teachers about the similarities and/or differences in teaching online versus in a classroom environment /

The introduction of computer and communications technology, and particularly the internet, into education has opened up some new possibilities for teaching and learning. Courses designed and delivered in an online environment offer the possibility of highly interactive and individually focussed teaching and learning experiences. However, online courses also present new challenges for both teachers and students. A qualitative study was conducted to explore teachers' perceptions about the similarities and differences in teaching in the online and face-to-face (F2F) environments. Focus group discussions were held with 5 teachers; 2 teachers were interviewed in depth. The participants, 3 female and 2 male, were full-time teachers from a large College of Applied Arts & Technology in southern Ontario. Each of them had over 10 years of F2F teaching experience and each had been involved in the development and teaching of at least one online course. i - -; The study focussed on how teaching in the online environment compares with teaching in the F2F environment, what roles teachers and students adopt in each setting, what learning communities mean online and F2F and how they are developed, and how institutional policies, procedures, and infrastructure affect teaching and learning F2F and online. This study was emic in nature, that is the teachers' words determine the themes identified throughout the study. The factors identified as affecting teaching in an online environment included teacher issues such as course design, motivation to teach online, teaching style, role, characteristics or skills, and strategies. Student issues as perceived by the teachers included learning styles, role, and characteristics or skills. As well, technology issues such as a reliable infrastructure, clear role and responsibilities for maintaining the infrastructure, support, and multimedia capability affected teaching online. Finally, administrative policies and procedures, including teacher selection and training, registration and scheduling procedures, intellectual property and workload policies, and the development and communication of a comprehensive strategic plan were found to impact on teaching online. The teachers shared some of the benefits they perceived about teaching online as well as some of the challenges they had faced and challenges they perceived students had faced online. Overall, the teachers feh that there were more similarities than differences in teaching between the two environments, with the main differences being the change from F2F verbal interactions involving body language to online written interactions without body language cues, and the fundamental reliance on technology in the online environment. These findings support previous research in online teaching and learning, and add teachers' perspectives on the factors that stay the same and the factors that change when moving from a F2F environment to an online environment.

Behavioural, mensural, and ecological correlates of polygyny in the eastern meadowlark (Sturnella magna)

During 1982 and 1983 I studied male attributes and attributes of the territory of male Eastern Meadowlarks (Sturnella magna) in order to determine whether there was a correlation between any of the attributes investigated and the number of females attracted by a male. Seventeen males, nine of which were polygynous and eight monogamous, were studied in 1982 and sixteen males.of which .. seven were polygynous and nine ~onogamous, were studied in 1983. The study was conducted in Short Hills Park, 10 km southwest of St. Catharines, Ontario and was designed to compare two hypotheses: the "sexy son" hypothesis (Weatherhead and Robertson,1977) and the polygyny threshold model (Verner and Willson,1966, Orians, 1969). Male attributes investigated were male size and song behaviour. Six measures of male size were taken: weight, flattened and natural wing chord length, culmen length, bill depth and length of the tarsometatarsus. In 1983 song repertoire size and song versatility measures were investigated. Attributes of the territory studied were: territory size, density of plant stems, percentage plant cover and measures of vegetation structure. In 1983 Arthropods were collected from each territory and sorted according to taxonomic group and size. During 1983, territory attributes were sampled twice, once early and once later in the nesting season. Analysis of data involved univariate comparisons between monogamous and polygynous males using T-tests and multivariate comparisons were made using discriminant function analysis (DFA) and principle components analysis (PCA).No correlations were found between the number of females attracted with, .ny measure of male size or with me, .sures of song versatili or size of song repertoire. Also no correlation was found between terri size and the number of females nesting on a terri . Some attributes of the male's terri id distinguish between monog,mous and po s males of thistudy. Analysis of Arthropod numbers showed that e~ .eran counts were significantly great~r on polygynous territories, a1 the total numb~rs of Arthropods collected showed no s fico .nt differences between territories of monogamous and po males. DFA chose ear teran and Hymenopteran counts as multivariate discriminators; both variables we' e more vegetation revealed that there were no univariate differences between the two groups of males fOT 1982 stem densities, but ~ spp. and Solidago spp. were chosen DFA as multivariate discriminators. The total number of plant stems and of Vicia spp. stems were s ficantly the early 1983 ing on monogamous territories for however DFA found no multivariate discriminators" Variables concerned with the overall aspects of vegetation structure showed significant differences between territories of monogamous and polygynous males. DFA of the 1982 sampling of vegetation structure showed significantly greater mat depth and vegetation height on polygynous territories, a finding which was not supported, however, by peA. For the early 1983 sampling period, plant height was greater on polygynous territories. Multivariate analysis identified greater green cover on polygynous territories, greater ground cover on monogamous territories, and greater depth of mat material on monogamous territories as discriminators between territories of monogamous and polygynous males. A DFA on the major variables of the study showed no significant difference between the territories of monogamous and polygynous male Meadowlarks. Of the correlations found, some were for non-prey Arthr~ods, for cover plants with very small samples sizes, or for variables which were greater for monogamous males during one sampling period and polygynous males during the next. While multivariate discriminators were found, peA showed no grouping of monogamous or polygynous males according to any of the variables investigated. On the basis of the univariate and multivariate analysis of major variables, I concluded that there were no correlations between the number of females attracted with male attributes and no unambiguous correlation with attributes of the territory. My study does not unequivocally support either the "sexy son" or the polygyny threshold hypothesis.

Generating Aesthetically Pleasing Images in a Virtual Environment using Particle Swarm Optimization

This research focuses on generating aesthetically pleasing images in virtual environments using the particle swarm optimization (PSO) algorithm. The PSO is a stochastic population based search algorithm that is inspired by the flocking behavior of birds. In this research, we implement swarms of cameras flying through a virtual world in search of an image that is aesthetically pleasing. Virtual world exploration using particle swarm optimization is considered to be a new research area and is of interest to both the scientific and artistic communities. Aesthetic rules such as rule of thirds, subject matter, colour similarity and horizon line are all analyzed together as a multi-objective problem to analyze and solve with rendered images. A new multi-objective PSO algorithm, the sum of ranks PSO, is introduced. It is empirically compared to other single-objective and multi-objective swarm algorithms. An advantage of the sum of ranks PSO is that it is useful for solving high-dimensional problems within the context of this research. Throughout many experiments, we show that our approach is capable of automatically producing images satisfying a variety of supplied aesthetic criteria.

Optimizing Computational Frameworks to Study the Influence of the Protein Environment on the Individual Site Energies of Chromophores in Photosystem II of Photosynthesis

Photosynthesis is a process in which electromagnetic radiation is converted into chemical energy. Photosystems capture photons with chromophores and transfer their energy to reaction centers using chromophores as a medium. In the reaction center, the excitation energy is used to perform chemical reactions. Knowledge of chromophore site energies is crucial to the understanding of excitation energy transfer pathways in photosystems and the ability to compute the site energies in a fast and accurate manner is mandatory for investigating how protein dynamics ef-fect the site energies and ultimately energy pathways with time. In this work we developed two software frameworks designed to optimize the calculations of chro-mophore site energies within a protein environment. The first is for performing quantum mechanical energy optimizations on molecules and the second is for com-puting site energies of chromophores in a fast and accurate manner using the polar-izability embedding method. The two frameworks allow for the fast and accurate calculation of chromophore site energies within proteins, ultimately allowing for the effect of protein dynamics on energy pathways to be studied. We use these frame-works to compute the site energies of the eight chromophores in the reaction center of photosystem II (PSII) using a 1.9 Å resolution x-ray structure of photosystem II. We compare our results to conflicting experimental data obtained from both isolat-ed intact PSII core preparations and the minimal reaction center preparation of PSII, and find our work more supportive of the former.

Bird depredation of grapes in Niagara vineyards : a novel approach to identifying spatial and temporal trends /

Although local grape growers view bird depredation as a significant economic issue, the most recent research on the problem in the Niagara Peninsula is three decades old. Peer-reviewed publications on the subject are rare, and researchers have struggled to develop bird-damage assessment techniques useful for facilitating management programmes. I used a variation of Stevenson and Virgo's (1971) visual estimation procedure to quantify spatial and temporal trends in bird damage to grapes within single vineyard plots at two locations near St. Catharines, Ontario. I present a novel approach to managing the rank-data from visual estimates, which is unprecedented in its sensitivity to spatial trends in bird damage. I also review its valid use in comparative statistical analysis. Spatial trends in 3 out of 4 study plots confirmed a priori predictions about localisation in bird damage based on optimal foraging from a central location (staging area). Damage to grape clusters was: (1) greater near the edges of vineyard plots and decreased with distance towards the center, (2) greater in areas adjacent to staging areas for birds, and (3) vertically stratified, with upper-tier clusters sustaining more damage than lower-tier clusters. From a management perspective, this predictive approach provides vineyard owners with the ability to identify the portions of plots likely to be most susceptible to bird damage, and thus the opportunity to focus deterrent measures in these areas. Other management considerations at Henry of Pelham were: (1) wind damage to ice-wine Riesling and Vidal was much higher than bird damage, (2) plastic netting with narrow mesh provided more effective protection agsiinst birds than nylon netting with wider mesh, and (3) no trends in relative susceptibility of varietals by colour (red vs green) were evident.

What nourishes the spirit of adolescents in the classroom? : a qualitative study into the gateways of adolescents' souls /

This thesis investigated the question, "What nourishes the adolescent spirit in the classroom?" Action research was conducted by the teacher of 16 grade 8 participants. By undergoing Kessler's (2000) "Passages Program," the students participated in 6 sessions which exposed them to a holistic intrapersonal curriculum. Student journal responses were documented after each session. The action researcher also kept journal reflections after each session. Upon completion of the 6 sessions, a postinterview was conducted which posed the research question. The research found that the adolescent spirit gets nourished through encouragement by the teacher, peers, and parents. This increases their competency, which increases their confidence, and ultimately their self-esteem goes up, which affects their selfconcept. In addition, the role of the teacher permeates every aspect of what nourishes the adolescent spirit in the classroom. In addition to the encouragement of the student, how a teacher teaches plays a vital role. A holistic approach to teaching provided the best atmosphere for the adolescent. It promoted creativity and choice, which stimulated the spirit of the adolescent. By working from a holistic philosophy, the teacher/action researcher created an environment conducive to teaching the whole person, which ultimately nourished the participants' spirit. The research highlighted that in order for this type of environment to exist the teacher needs to make a conscious and deliberate effort to look within and develop their inner self before they can begin to promote this type of classroom for the adolescents they teach. When teachers and students develop an inner life together, they can begin to work in harmony to achieve an atmosphere where the teaching and learning environment becomes one seamless transaction. Only then can one's whole potential be realized.

Opening a can of worms : perceptions and practices of teachers in Newfoundland and Labrador incorporating the role of a therapist

Educational trends of inclusion and collaboration have led to changing roles of teachers, including an emphasis on personal support. To provide for social, emotional, and behavioural needs, teachers may adopt a therapeutic role. Many models for such support are proposed, with most models including the importance of student-teacher relationships, a focus on social, emotional, and behavioural development, and direct instruction of related skills. This study includes 20 interview participants. In addition, 4 of the 20 interview participants also took part in a case study. It examines whether participants adopt a therapeutic role, their beliefs about student-teacher relationships, whether they provide interventions in personal issues, and instructed social, emotional, and behaviour skills. Findings show that teachers adopt an academic role as well as a therapeutic role, believe student-teacher relationships are important, are approached about personal issues, and instruct social, emotional, and behavioural skills. Talking and listening are commonly used to provide support, typically exclusive of formal curricular goals. The challenges in providing front-line support issues that may be shared within an established student-teacher relationship are considered. Support in turn for teachers who choose to provide support for personal issues in the classroom within a therapeutic role are suggested, including recommendations for support and referral related to specific social, emotional, or behavioural scenarios that may arise in the school community.

Perceptions of creativity in a fashion design course /

Creativity is important to the growth and development of society, to educational institutions, and to the personal growth of individuals. Students who are aware of their creativity are assumed to have innovative ideas and fresh insights. Limited research has been conducted to see if students can identify their own creative abilities. In this study, I explored the students' perceptions and experiences in a fashion design course. This study documented the creative journey from the concept stage of an apparel collection to the final product. Participants were asked to reflect and document their creative moments, describe a creative process, and identify a creative environment. The participants were students who were enrolled in a fashion design course and were asked to participate in this study because they experienced all stages of the design process. Data were collected through personal reflection surveys, focus groups, and personal interviews. Themes of creative moments that emerged from this study were experiences that the participants had as they proceeded through the stages of the fashion design process. All of the participants identified a creative process, but the stages varied for each participant The participants identified themes related to promoting creativity in an environment, including the atmosphere, creative people, teachers, reflection, student needs, and assignments. The participants identified potential barriers in an environment, including rules and guidelines, teachers, the classroom, deadlines and time, feedback, and other important issues. The results ofthis study suggest that there needs to be a better understanding of creativity and greater support and encouragement for creativity in the classroom. Instructors need to support environments that are conducive to creative development and lead to effective learning for students. Students need to learn how to enhance their creativity as well as understand the barriers that block their creative development.

Responses of crayfish to a reflective environment /

This thesis examines how dominance status of crayfish alters responses to their own reflection. Crayfish are social animals that fight to develop a dominance hierarchy consisting of dominant and subordinate members. After socialization, crayfish were videotaped in an aquarium with mirrors on one half of the tank and a non-reflective plastic on the other half. Dominants paired for 14 days perform more cornering, turning, crossing and spent more time in a reflective environment versus a non-reflective environment. Subordinate crayfish exhibit more reverse walking in a mirrored environment while isolated crayfish show no preference for reflection. This change in behaviour occurs immediately for dominants paired for 30 min while subordinates require 3 days of pairing to exhibit the same behaviour as subordinate crayfish paired for 14 days. Thus, 30 min of pairing is required to enhance responses to a reflection observed in dominant crayfish while 3 days is required to decrease subordinate responses to a reflection. These findings propose that male socialized crayfish respond to their mirror image as they do a male conspecific. Their responses depend on both their dominance status and the length of socialization which suggests that crayfish are learning to behave in a characteristic manner as a result of their social experience.

A comparative study of the change in diatom inferred ph of a staircase of lakes in the Algoma District, Northern Ontario /

Four staircase lakes occupying a single watershed located in the Algoma District, north of Lake Superior were chosen for this study. I examined the subfossil diatom assemblage in the top twenty centimeters of the surface sediments in each of these four lakes in an attempt to reconstruct their respective past pH history. From these analyses it was possible to test the hypothesis that the rate of change of diatom inferred pH was not significantly different in lakes located one below the other in a single "staircase" within a single watershed system. My results indicated that the four Z lakes had been acid for at least the last century. The water color of the three upper Z lakes (Z1, Z2 and Z3) was brown (>30 Pt Co units). The bottom lake (Z4) was the only clear water lake in the system «5 Pt Co units). This bottom staircase lake had no muskeg development around its shoreline. The alkaliphilous diatoms in the Z watershed system were important in determining the diatom inferred pH of the four Z lakes. The centric diatoms were extremely rare in the clearwater bottom lake (Z4). The ecology of the Eupodiscales is perhaps important in the interpretation of sediment in the more acid environment. Lake Z4 was the only one that had a progressive as well as a significant decrease in its downcore diatom inferred pH since the early 1960's. This lead me to speculate that the humic substances present in the upper three brown water lakes (Z1, Z2 and Z3) were perhaps Important in buffering them against a further decrease in water pH even though they were located within an area which was sensitive to acid precipitation.

Postglacial paleoecology and effects of European settlement on the environment of Lake Hunger and Lake Lisgar, Southwestern Ontario /

This investigation has three purposes I to make a comparative chemical study on sediment cores collected for Lake Lisgar (man-made lake in an urban center) and Lake Hunger (natural basin in a rural community) encompassing the time since European settlement I to determine the postglacial chemical history of Lake Hunger, and to determine the vegetational history of the Lake Hunger area from postglacial time to the present. The minus 80 mesh fraction of 108 soil samples and 18 stream sediment samples collected in the vicinity of Lakes' Lisgar and Hunger were analyzed for cold hydrochloric acid soluble lead, zinc, nickel, cobalt, copper, aluminum, sodium, potassium, calcium, magnesium, iron and manganese. Lacustrine sediments from 5 boreholes in the Lake Lisgar basin were collected. Boreholes 1, 2, 3, and 4 were analyzed for palynological and chemical information and Borehole 5 was subjected to pollen and ostracode analysis. Lacustrine sediments from 6 boreholes in the Lake Hunger basin were collected. Palyno- -logical and chemical analysis were performed on Boreholes 1, 2, 3, 4, and 6 and Borehole 5 was analyzed for pollen. In addition, radiocarbon dates were obtained on sediment samples from Boreholes 4 and 5. A total of 8 surface samples were collected from the margins of the Lake Hunger basin and these were chemically analyzed in the laboratory. All of the lacustrine sediments were ashed and analyzed for cold hydrochloric acid soluble lead, zinc, nickel, cobalt, copper, aluminum, sodium, potassium, calcium, magnesium, iron and manganese using a Perkin Elmer 40) Atomic Absorption spectrophotometer. The results . obtained for the 12 elements were expressed as parts per million in dry sediments. It was found that man's influence on the element distribution patterns in the sediments of Lake Lisgar appeared to be related to his urbanizing developments within the lake vicinity, whereas, the rural developments in the vicinity of lake Hunger appeared to have had little effect on the element distribution patterns in the lake sediments. The distribution patterns of lead, zinc, nickel, cobalt, aluminum, magnesium, sodium and potassium are similar to the % ash curve throughout postglacial time indicating that the rate of erosion in the drainage basin is the main factor which controls the concentration of these elements in the sediments of Lake Hunger. The vegetational history, from palynological analysis, of Lake Hunger from postglacial time to the present includes the following stages: tundra, open spruce forest, closed boreal forest, deciduous forest and the trend towards the re-establishment of pine following the clearing of land and the subsequent settlement of the Lake Hunger area by European settlers. The concentrations of some elements (cobalt, nickel, iron, manganese, calcium, magnesium, sodium and potassium) in the sediments of Lake Hunger appears to be higher during pre-cultural compared to post-cultural times. At least one complete postglacial record of the chemical history within a lake basin is necessary in order to accurately assess man's effects on his environment.

Thermoaclimatory variations in the microenvironment of hemoglobin in the rainbow trout, Salmo gairdneri and the carp, Cyprinus carpio

Several inorganic substances (e.g., C£ , Mg , Ca , H ) are potent negative modulators of hemoglobin-oxygen affinity. To evaluate the possibility that potentially adaptive changes in the red cell ionic environment of hemoglobin may take place during acclimation of fishes to increased environmental temperature, hematological status (hemoglobin, hematocrit, red cell numbers, mean erythrocytic volume and hemoglobin content), plasma + + 2+ 2+ and packed red cell electrolyte levels (Na , K , Ca , Mg , C£ ) were evaluated in summer and winter populations of the stenothermal rainbow trout, Salmo gairdneri, following acclimation to 2°, 10°, 18°C, and in a spring population of eurythermal carp, Cyprinus carpio, held at 2°, 16° and 30°C. From these data cell ion concentrations and ion:hemoglobin ratios were estimated. In view of the role of red cell carbonic anhydrase in the reductions of blood C02 tensions and the recruitment of Na and C£~ lost by fishes, a preliminary investigation of thermoacclimatory changes in the activity of this system in rainbow trout erythrocytes was conducted. Few changes in hematological status were encountered following acclimation. There was, however, some evidence of weight-specific differential hematological response in carp. This lead to markedly greater increases in hemoglobin, hematocrit and red cell numbers in smaller rather than in larger specimens at higher temperatures; variations which were 2+ well correlated with changes in plasma Ca . Plasma composition in summer trout was not altered by acclimation. In winter trout plasma Na and K increased at higher temperatures. Carp were characterized by increases in plasma calcium, and reductions in sodium and magnesium under these conditions. Several significant seasonal differences in plasma ion levels were observed in the trout. (n) In trout, only erythrocytic K and K :Hb were altered by acclimation, rising at higher temperatures. In carp Na , Na :Hb, C£~ and C£~:Hb in- 2+ 2+ creased with temperature, while Mg and Mg :Hb declined. Changes in overall ionic composition in carp red cells were consistent with increases in H content. In both species significant reciprocal variations in C£~ 2+ - + and Mg were found. In mammalian systems increases in C£ and H reduce hemoglobin-oxygen affinity by interaction with hemoglobin. Reduction in 2+ 2+ Mg maximizes organophosphate modulator availability by decreasing ATP»Mg complex formation. Thus, the changes observed may be of adaptive value in reducing hemoglobin-oxygen affinity, and facilitating oxygen release to cells at higher temperatures. Trout appear to maintain a high chloridelow magnesium state over the entire thermal tolerance zone. Carp, however, achieved this state only at higher temperatures. In both species mean erythrocytic volume was decreased at higher temperatures and this may facilitate branchial oxygen loading. Since mean erythrocytic volume was inversely related to red cell ion content, it is hypothesized that reductions in cell volume are achieved by export of some unidentified solute or solutes. Variations in the carbonic anhydrase activity that could be attributed to the thermoacclimatory process were quite modest. On the other hand, assays performed at the temperature of acclimation showed a large temperature effect where under in vivo conditions of temperature fish acclimated to higher temperatures might be expected to have higher activities. Furthermore, since hematocrit increased with temperature in these fish, while carbonic anhydrase is present only in the erythrocyte, the whole blood levels of this enzyme are expected to increase and further augment the temperature effect. This, in turn, could aid in the reduction of C02 (111) tension and increase the production of H and HC0~~ used in the active uptake of Na and C£ at higher temperatures.

Foraging ecology and parental care of common terns (Sterna hirundo) nesting in Windermere Basin, Lake Ontario

The relationships among chick feeding, size and type of prey item, and foraging time away from the brood have not been well studied in seabirds. This study investigated spatial and temporal patterns of foraging and chick-provisioning among 23 radio-tagged male common terns nesting at Hamilton Harbour, Lake Ontario during 1991 and 1992. Telemetry data were collected concurrently with behavioural observations from an elevated blind. Terns fitted with transmitters did not differ from controls with respect to either brood attendance, patterns of chick mortality, species and size distributions of prey delivered to offspring, or chick-provisioning rates. There was a clear separation of parental roles: males were primarily responsible for feeding chicks while females allocated more time to brood attendance. The prey species most commonly delivered to chicks by adults were rainbow smelt (Osmerus mordax) and alewife (A/osa pseudoharengus), followed in importance by larval fish, emerald shiner (Notropis antherinoides), salmonids, and fathead minnows (Pimepha/es prome/as). The relative proportions of various fish speCies delivered to chicks by males differed over the course of each breeding season, and there was also much variability in species composition of prey between years. Sizes of prey delivered to chicks also differed between sampling periods. The modal size of fish brought to chicks during Peak 1991 was 1.5 bill lengths, while the majority of prey in Late 1991 were small larval fish. The reverse trend occurred in 1992 when small fish were delivered to chicks predominantly during the Peak nesting period. During periods when predominantly small fish were delivered to chicks, the foraging activity of radio-tagged males was concentrated within a two kilometer radius of the colony. The observed variation in prey composition and foraging locations during the study likely reflects temporal variation in the availability of prey in the vicinity of the colony. Males delivered fish to chicks at a constant rate, while females 4 increased their feeding frequency over the first six to ten brood days. The mean length of fish delivered to chicks by adults increased significantly with increasing chick age. As a group, within each nesting period, transmittered males either foraged predominantly in the same directional bearing (north during Peak 1991, south during Late 1992), or concentrated foraging activity in the immediate vicinity of the colony (Late 1991, Peak 1992). However, individual radio-tagged males exhibited unique and predictable foraging patterns, often favouring specific locations within these areas and differing in their secondary foraging patterns. Overall, the Lake Ontario shoreline between NCB Bay" (3.5 km south of colony) and the lift bridge canal (4 km north of colony) was the foraging area used most frequently by radiotagged males during the chick-rearing period. Foraging patterns of transmittered males at Windermere Basin are similar to patterns of peak-nesting common terns, but differ from those of late-nesters, at a nearby colony (Port Colborne, Lake Erie). Differences between the foraging patterns of late-nesting terns at these colonies likely reflect differences in annual patterns of fish availability between the two locations. No relationship was found between foraging proficiency of adults and survival of offspring. Stochastic factors, such as predation by black-crowned nightherons (Nycticorax nycticorax) and adverse weather conditions during the early stages of chick rearing, may be more important determinants of common tern breeding success than parental quality or fish availability.