Digestion Strategies of North Atlantic Seabirds

Studies on digestion in North Atlantic seabirds are presented, with particular emphasis on the relationships between digestion and ecology. A negative relationship between the rate of digestion and digestive efficiency is shown to occur in an inter-specific comparison of eight North Atlantic seabird species. This relationship is interpreted as representing a trade-off between benefits of rapid digestion and benefits of high digestive efficiency. Digestion rate is related to gut morphology: species with small guts tend to have rapid digestion. The selection pressures which result in species adopting a given digestion strategy are considered. Species with opportunistic feeding habits, and which include low quality food in their diets, tend to have slow but efficient digestion, whereas species which specialise on highly digestible and energy dense fish prey tend to adopt a strategy of rapid but inefficient digestion. It is suggested that slow digestion and a large gut is a requirement for species consuming low quality prey. A modelling approach indicates that digestion strategy can also have a profound effect on time and energy budgets of seabirds. In terms of time and energy minimisation, rapid digestion is likely to be favoured when costs of flight to the foraging site are high (in energy or time). An ingestion bottleneck is identified, which limits feeding rates when the gut is full, and thus applies strong selection pressure on optimal feeding trip length. The responses to digestive challenges of a specialist piscivore (Common Guillemot) and an opportunistically feeding seabird (Lesser Black-backed Gull) are compared. Birds were acclimated to one fish diet, and then abruptly switched to a novel diet. There is evidence that switched birds have non-optimal digestion of the novel diet, when compared with birds which are acclimated to that diet. The costs of diet switching are greater for Common Guillemots. The digestive cost of eating a mixed diet of two different fish types, when compared to eating the same diets separately, is also examined. For Common Guillemots digestive efficiency is significantly lower on the mixed diet, but no such cost is apparent for Lesser Black-backed Gulls. Thus the decision to change between diets should be affected by digestive considerations, even when the difference between diets is slight. It appears that species which commonly eat a varied diet are less affected by such digestive challenges. The relationship between diet characteristics and retention time are examined in a range of seabird species. Different fish species are digested at different rates, and these differences tend to be consistent across seabird species. Ease of digestion, energy density and nutrient composition should be considered as separate attributes of a diet, all of which may affect optimal retention time. The criterion by which optimal retention time is set in seabirds is unclear: they may be net rate maximisers, or efficiency maximisers. Geographic variation in the gut morphology and other major body organs is demonstrated within six Icelandic seabird species. This variation is consistent among species, and is related to geographic variation in ecological conditions, namely diet, foraging range and climate. Such variation in body composition between areas has not previously been shown, and may be an important component of adaptation to local habitat

USING DIGITAL PHOTOGRAPHY TO SUPPORT TEACHING AND LEARNING OF PROPORTIONAL REASONING CONCEPTS

Abstract Proportional reasoning entails multiplicative relationships in situations of comparison. Successful proportional reasoners can recognise a proportional situation as distinct from a non-proportional one; they have a sense of co-variation and they have a range of strategies for solving proportional problems. As educators we realise that teaching proportional reasoning cannot solely rely on asking students to complete symbolic and mechanical methods, such as the cross-product algorithm. To develop proportional reasoning, students must have regular opportunities to experience the underlying concepts. These concepts include foundational aspects of proportional reasoning, such as fractional thinking, multiplicative thinking (as opposed to additive), relative thinking (as opposed to absolute), as well as concepts of rate and scale. As part of a large multi-state project in Australia to enhance middle years students' numeracy through a focus on proportional reasoning, 120 teachers participated in a series of professional learning workshops. These teachers generally reported feeling confident teaching the algorithmic aspects of proportional reasoning but a number of them specifically asked for assistance with the conceptual development of their students' proportional reasoning. In response, the researchers developed a series of activities with the teachers, where digital cameras were used in the school environs to capture images that represented examples of proportional reasoning concepts. In small groups, the teachers moved around the school taking their photos and then reported back to the workshop, showing their images through a data projector while they explained the concepts they felt their images captured. This presentation articulates the ways that the digital cameras were used by the teachers to capture and report on the proportional reasoning concepts, and their thoughts and aspirations as to how they would use the cameras to develop the proportional reasoning of their students

Parent support advisor pilot : first interim report from the evaluation

The Parent Support Adviser (PSA) pilot is a government funded initiative to support 20 Local Authorities (LAs) to introduce PSAs into their workforce. The Department for Children, Schools and Families (DCSF) commissioned the Centre for Educational Development, Appraisal and Research (CEDAR) to evaluate the PSA pilot programme from September 2006 – August 2008. A government grant (£40 million) has been made available to fund employment of PSAs over this period. To date, 717 PSAs are in place, supporting parents in 1167 schools. This first Interim Report is based on semi-structured interviews with 97 PSAs, 85 line managers and 23 other professionals in 12 case study LAs during Phase 1 of the evaluation, which was carried out between April and June 2007. Phase 2 of the study will take place during the period October to December 2007; phase 3 will take place during March to June 2008. In addition to these interview-based studies with the 12 case study LAs, an analysis will be made of the data collected by all 20 LAs over the period of the pilot using a standard database devised by CEDAR. Data are being collected on the PSAs’ work with parents and, where this occurs, with children. Finally, a cost effectiveness study will be undertaken. The findings from these phases of the project will be reported in the final report

Cell exclusion in couette flow:evaluation through flow visualisation and mechanical forces

Cell exclusion is the phenomenon whereby the hematocrit and viscosity of blood decrease in areas of high stress. While this is well known in naturally occurring Poiseuille flow in the human body, it has never previously been shown in Couette flow, which occurs in implantable devices including blood pumps. The high-shear stresses that occur in the gap between the boundaries in Couette flow are known to cause hemolysis in erythrocytes. We propose to mitigate this damage by initiating cell exclusion through the use of a spiral-groove bearing (SGB) that will provide escape routes by which the cells may separate themselves from the plasma and the high stresses in the gap. The force between two bearings (one being the SGB) in Couette flow was measured. Stained erythrocytes, along with silver spheres of similar diameter to erythrocytes, were visualized across a transparent SGB at various gap heights. A reduction in the force across the bearing for human blood, compared with fluids of comparable viscosity, was found. This indicates a reduction in the viscosity of the fluid across the bearing due to a lowered hematocrit because of cell exclusion. The corresponding images clearly show both cells and spheres being excluded from the gap by entering the grooves. This is the first time the phenomenon of cell exclusion has been shown in Couette flow. It not only furthers our understanding of how blood responds to different flows but could also lead to improvements in the future design of medical devices

Status assessment of the Critically Endangered Azores Bullfinch Pyrrhula murina

13 páginas, 4 figuras, 1 tabla.The Azores Bullfinch is endemic to the island of São Miguel (Azores, Portugal). Its status was uplisted to Critically Endangered in 2005 on the basis of an extremely small and declining population that was considered to be restricted to a very small mountain range (43 km2), in a single location, within which the spread of invasive plants constituted a threat to habitat quality. Nevertheless, information was mostly inferred, or the product of, non-systematic studies. In order to carry out a complete assessment of the conservation status we analysed: (i) population trend, calculated from annual monitoring 1991–2008, (ii) population size, and (iii) range size, obtaining estimates in a single morning study in 2008 involving the simultaneous participation of 48 observers. Contrary to previous inferences, the population is no longer decreasing, although quality of laurel forest habitat continues to decline due to the persistent threat of invasive species. Population size (mean ± SE) was estimated at 1,064 ± 304 individuals using distance sampling methods, although the estimate was very sensitive to the survey method used. Range size estimates (extent of occurrence and area of occupancy) were 144 km2 and 83 km2 respectively. Given the present information, we propose the downlisting of Azores Bullfinch to Endangered on the IUCN Red List.Este trabajo fue parte del programa "Azores Bullfinch monitoring" incluído en el proyecto de la Comisión Europea, LIFE NAT/P/000013 “Recovery of Azores Bullfinch’s habitat in the Special Protection Area of Pico da Vara / Ribeira do Guilherme”.Peer reviewe

Wildlife health outcomes and opportunities in conservation translocations

It is intuitive that the health status of wildlife might influence conservation translocation outcomes, however, health as a topic has received limited attention in the conservation translocation literature. We determined the forms and frequency of disease and other biological problems reported in translocated animals and plants, and in populations linked to translocation, and associations between their mention and translocation ‘success’. From these problems we deduced the forms of ill-health potentially associated with conservation translocation and developed contextual frameworks to inform health management

Behavioural and energetic consequences of competition among three overwintering swan (Cygnus spp.) species

Funder: Peter Scott Trust for Education and Research in ConservationFunder: Peter Smith Charitable Trust for NatureFunder: Olive Herbert Charitable TrustFunder: D’Oyly Carte Charitable TrustFunder: N. Smith Charitable SettlementFunder: Robert Kiln Charitable TrustFunder: The estate of the late Professor Geoffrey Matthews OBEAbstractBackgroundWinter numbers of the northwest European population of Bewick’s Swans (Cygnus columbianus bewickii) declined recently by c. 40%. During the same period, numbers of two sympatric and ecologically-similar congeners, the Mute Swan (Cygnus olor) and Whooper Swan (Cygnus cygnus) showed increases or stability. It has been suggested that these opposing population trends could have a causal relationship, as Mute and Whooper Swans are larger and competitively dominant to Bewick’s Swans in foraging situations. If so, effects of competition of Mute and Whooper Swans on Bewick’s Swans should be detectable as measurable impacts on behaviour and energetics.MethodsHere, we studied the diurnal behaviour and energetics of 1083 focal adults and first-winter juveniles (“cygnets”) of the three swan species on their winter grounds in eastern England. We analysed video recordings to derive time-activity budgets and these, together with estimates of energy gain and expenditure, were analysed to determine whether individual Bewick’s Swans altered the time spent on key behaviours when sharing feeding habitat with other swan species, and any consequences for their energy expenditure and net energy gain.ResultsAll three swan species spent a small proportion of their total time (0.011) on aggressive interactions, and these were predominantly intraspecific (≥ 0.714). Mixed-effects models indicated that sharing feeding habitat with higher densities of Mute and Whooper Swans increased the likelihood of engaging in aggression for cygnet Bewick’s Swans, but not for adults. Higher levels of interspecific competition decreased the time spent by Bewick’s Swan cygnets on foraging, whilst adults showed the opposite pattern. When among low densities of conspecifics (&lt; c. 200 individuals/km2), individual Bewick’s Swans spent more time on vigilance in the presence of higher densities of Mute and Whooper Swans, whilst individuals within higher density Bewick’s Swan flocks showed the opposite pattern. Crucially, we found no evidence that greater numbers of interspecific competitors affected the net energy gain of either adult or cygnet Bewick’s Swans.ConclusionsWe found no evidence that Bewick’s Swan net energy gain was affected by sharing agricultural feeding habitat with larger congeners during winter. This was despite some impacts on the aggression, foraging and vigilance behaviours of Bewick’s Swans, especially among cygnets. It is unlikely therefore that competition between Bewick’s Swans and either Mute or Whooper Swans at arable sites in winter has contributed to the observed decline in Bewick’s Swan numbers. Further research is needed, however, to test for competition in other parts of the flyway, including migratory stopover sites and breeding areas.</jats:sec