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

Potential Hazard to Human Health from Exposure to Fragments of Lead Bullets and Shot in the Tissues of Game Animals

Peer reviewedPublisher PD

Ethical considerations when conservation research involves people

Social science is becoming increasingly important in conservation, with more studies involving methodologies that collect data from and about people. Conservation science is a normative and applied discipline designed to support and inform management and practice. Poor research practice risks harming participants, researchers, and can leave negative legacies. Often, those at the forefront of field‐based research are early‐career researchers, many of whom enter their first research experience ill‐prepared for the ethical conundrums they may face. Here, we draw on our own experiences as early‐career researchers to illuminate how ethical challenges arise during conservation research that involves human participants. Specifically, we discuss ethical review procedures, conflicts of values, and power relations, and provide broad recommendations on how to navigate ethical challenges when they arise during research. We encourage greater engagement with ethical review processes and highlight the pressing need to develop ethical guidelines for conservation research that involves human participants.Output Status: Forthcoming/Available Onlin

Data from: Inter-annual variability and long-term trends in breeding success in a declining population of migratory swans

Population declines among migratory Arctic-breeding birds are a growing concern for conservationists. To inform the conservation of these declining populations, we need to understand how demographic rates such as breeding success are influenced by combinations of extrinsic and intrinsic factors. In this study we examined inter-annual variation and long-term trends in two aspects of the breeding success of a migratory herbivore, the Bewick's swan Cygnus columbianus bewickii, which is currently undergoing a population decline: 1) the percentage of young within the wintering population and 2) mean brood size. We used an information-theoretic approach to test how these two measures of productivity were influenced over a 26 yr period by 12 potential explanatory variables, encompassing both environmental (e.g. temperature) and intrinsic (e.g. pair-bond duration) factors. Swan productivity exhibited sensitivity to both types of explanatory variable. Fewer young were observed on the wintering grounds in years in which the breeding period (May to September) was colder and predator (Arctic fox) abundance was higher. The percentage of young within the wintering population also showed negative density-dependence. Inter-annual variance in mean swan brood size was best explained by a model comprised of the negative degree days during the swan breeding period, mean pair-bond duration of all paired swans (i.e. mean pair duration), and an interaction between these two variables. In particular, mean pair duration had a strong positive effect on mean brood size. However, we found no long-term directional trend in either measure of breeding success, despite the recent decline in the NW European population. Our results highlight that inter-annual variability in breeding success is sensitive to the combined effects of both intrinsic and extrinsic factors

Wood et al 2016 Bewick Swan breeding success paper data

A Microsoft Excel spreadsheet containing the raw and standardized values for all variables used in the analysis of Bewick's Swan breeding success. The data cover the period 1988-2013. A legend describing the identity of each variable is also included. Further information on the data analysis is available in the published paper

Ramsar wetland disease manual : guidelines for assessment, monitoring and management of animal disease in wetlands

This manual was prepared by the Wildfowl & Wetlands Trust (WWT) for the Ramsar Convention on WetlandsContributing authors: Melba B. Reantaso, Kojo Yamamoto, Louise Hurst, Mechthild H. Adameit, Martin Wiese, A. Al-Asadi, M. TalibTechnical editors: Ashley Banyard, Richard Botzler, Katie Colvile, Andrew Cunningham, Paul Duff, Henrik Enevoldsen, Paul Holmes, Daniel Horton, Pierre Horwitz, Emma Hutchins, Richard Irvine, Florian Keil, Richard Kock, Becki Lawson, Lindsey McCrickard, Birgit Oidmann, Edmund Peeler, L. Paul Phipps, Mark Simpson, Matthew Simpson & Alexandra TomlinsonThe Manual highlights the importance of including disease prevention and control in wetland management plans and provides how-to guidelines. It is to be used in conjunction with Ramsar Handbook No. 18 on Managing Wetlands. This Manual is not intended as in-depth technical guidance for dealing with specific disease issues, but as a primer for wetland managers and policy makers, describing the key components of disease prevention and control strategies, and directing the reader to the primary sources, where more information can be obtained. The Ramsar Convention on Wetlands of International Importance is an international treaty for the conservation and sustainable use of wetlands

Demographic rates reveal the benefits of protected areas in a long-lived migratory bird

Recent studies have suggested that protected areas often fail to conserve target species. However, the efficacy of terrestrial protected areas is difficult to measure, especially for highly vagile species like migratory birds that may move between protected and unpro-tected areas throughout their lives. Here, we use a 30-y dataset of detailed demographic data from a migratory waterbird, the Whooper swan (Cygnus cygnus), to assess the value of nature reserves (NRs). We assess how demographic rates vary at sites with varying levels of protection and how they are influenced by movements between sites. Swans had a lower breeding probability when wintering inside NRs than outside but better survival for all age classes, generating a 30-fold higher annual growth rate within NRs. There was also a net movement of individuals from NRs to non-NRs. By combining these demographic rates and estimates of movement (into and out of NRs) into popu-lation projection models, we show that the NRs should help to double the population of swans wintering in the United Kingdom by 2030. These results highlight the major effect that spatial management can have on species conservation, even when the areas protected are relatively small and only used during short periods of the life cycle.Peer reviewe