30 research outputs found

    Decline in an Atlantic Puffin population : evaluation of magnitude and mechanisms

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    Funding: This study was funded annually by Fair Isle Bird Observatory Trust (www.fairislebirdobs.co.uk) with contributions from the Joint Nature Conservation Committee (jncc.defra.gov.uk). Funding was received from these two sources by Fair Isle Bird Observatory from 1986 to 2013. The Joint Nature Conservation Committee and Fair Isle Bird Observatory Trust supplied guidance on study design, data collection, analyses, preparation of the manuscript and the decision to publish.Peer reviewedPublisher PD

    Quantifying full phenological event distributions reveals simultaneous advances, temporal stability and delays in spring and autumn migration timing in long-distance migratory birds

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    Acknowledgements We thank all Fair Isle Bird Observatory staff and volunteers for help with data collection and acknowledge the foresight of George Waterston and Ken Williamson in instigating the observatory and census methodology. We thank all current and previous directors of Fair Isle Bird Observatory Trust for their contributions, particularly Dave Okill and Mike Wood for their stalwart support for the long-term data collection and for the current analyses. Dawn Balmer and Ian Newton provided helpful guidance on manuscript drafts. We thank Ally Phillimore and two anonymous referees for helpful comments. This study would have been impossible without the Fair Isle community's invaluable support and patience over many decades, which is very gratefully acknowledged. WTSM and JMR designed and undertook analyses, wrote the paper and contributed to data collection and compilation, MB contributed to analysis and editing, all other authors oversaw and undertook data collection and compilation and contributed to editing.Peer reviewedPostprin

    Among‐species variation in six decades of changing migration timings explained through ecology, life‐history and local migratory abundance

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    We thank all Fair Isle residents for their long-term support, and W.T.S. Miles and I.J. Andrews for database construction and management. V.R.D was funded by a UK NERC SUPER DTP PhD studentship supported by University of Aberdeen and Fair Isle Bird Observatory Trust.Species exploiting seasonal environments must alter timings of key life‐history events in response to large‐scale climatic changes in order to maintain trophic synchrony with required resources. Yet, substantial among‐species variation in long‐term phenological changes has been observed. Advancing from simply describing such variation towards predicting future phenological responses requires studies that rigorously quantify and explain variation in the direction and magnitude of changing timings across diverse species in relation to key ecological and life‐history variables. Accordingly, we fitted multi‐quantile regressions to 59 years of multi‐species data on spring and autumn bird migration timings through northern Scotland. We demonstrate substantial variation in changes in timings among 72 species, and tested whether such variation can be explained by species ecology, life‐history and changes in local abundance. Consistent with predictions, species that advanced their migration timing in one or both seasons had more seasonally restricted diet types, fewer suitable breeding habitat types, shorter generation lengths and capability to produce multiple offspring broods per year. In contrast, species with less seasonally restricted diet types and that produce single annual offspring broods, showed no change. Meanwhile, contrary to prediction, long‐distance and short‐distance migrants advanced migration timings similarly. Changes in migration timing also varied with changes in local migratory abundance, such that species with increasing seasonal abundance apparently altered their migration timing, whilst species with decreasing abundance did not. Such patterns broadly concur with expectation given adaptive changes in migration timing. However, we demonstrate that similar patterns can be generated by numerical sampling given changing local abundances. Any apparent phenology‐abundance relationships should, therefore, be carefully validated and interpreted. Overall, our results show that migrant bird species with differing ecologies and life‐histories showed systematically differing phenological changes over six decades contextualised by large‐scale environmental changes, potentially facilitating future predictions and altering temporal dynamics of seasonal species co‐occurrences.Peer reviewe

    Interspecific variation in non-breeding aggregation: a multi-colony tracking study of two sympatric seabirds

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    Migration is a widespread strategy for escaping unfavourable conditions during winter, but the extent to which populations that segregate during the breeding season aggregate during the non-breeding season is poorly understood. Low non-breeding season aggregation may be associated with higher likelihood of overlap with threats, but with fewer populations affected, whereas high aggregation may result in a lower probability of exposure to threats, but higher overall severity. We investigated non-breeding distributions and extent of population aggregation in 2 sympatrically breeding auks. We deployed geolocation-immersion loggers on common guillemots Uria aalge and razorbills Alca torda at 11 colonies around the northern UK and tracked their movements across 2 non-breeding seasons (2017-18 and 2018-19). Using 290 guillemot and 135 razorbill tracks, we mapped population distributions of each species and compared population aggregation during key periods of the non-breeding season (post-breeding moult and mid-winter), observing clear interspecific differences. Razorbills were largely distributed in the North Sea, whereas guillemot distributions were spread throughout Scottish coastal waters and the North, Norwegian and Barents Seas. We found high levels of aggregation in razorbills and a strong tendency for colony-specific distributions in guillemots. Therefore, razorbills are predicted to have a lower likelihood of exposure to marine threats, but more severe potential impact due to the larger number of colonies affected. This interspecific difference may result in divergent population trajectories, despite the species sharing protection at their breeding sites. We highlight the importance of taking whole-year distributions into account in spatial planning to adequately protect migratory species.</jats:p

    The remaining koalas (Phascolarctos cinereus) of the Pilliga forests, north-west New South Wales: Refugial persistence or a population on the road to extinction?

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    In the 1990s, the Pilliga forests were carrying the largest population of koalas west of the Great Dividing Range in New South Wales (NSW). Whereas the NSW koala population in its entirety was thought to be in decline, the Pilliga population stood out as potentially increasing. By 2007, anecdotal evidence suggested that the population was in decline. We undertook surveys of koalas in the Pilliga forests that repeated surveys undertaken between 1991 and 2011. We found that koalas had declined and were found in only 21% of sites in which they were observed in the initial surveys-by any measure, a 5-fold drop in occupancy in less than two decades is severe. Declines occurred evenly across the Pilliga, with persistence at a site seemingly related to a high initial density of koalas rather than to a slower rate of decline. Sites where koalas persisted were characterised as having higher temperatures and lower rainfall relative to other sites, being close to drainage lines with deeper soils and having a lower occurrence of fire. This pattern fits with the observation in the recent surveys that koalas were next to drainage lines in the western half of the Pilliga and fits with the suggestion that koalas show refugial persistence. Recovery from this point is not assured and will depend on how we manage the landscape, particularly with the threat of climate change. This will likely require active management within an adaptive management framework, such as restoration of refuges, and not simply habitat reservation

    Population size estimates for Atlantic Puffin and Great Skua.

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    <p>A. The maximum count of individual adult Atlantic Puffins on Fair Isle in census years between 1986 and 2013 and B. the total number of Great Skua nesting pairs (apparently occupied territories) on Fair Isle in 1987 to 2013.</p

    Drawn to Change : Graphic Histories of Working-Class Struggles

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    " Drawn to Change offers inspiring histories of working-class struggle in a short and easy-to-read format. The collection features nine comics ranging in length from 10 to 30 pages. These comics were completed as part of the Graphic History Project and which highlight different aspects of Canadian labour history. As a whole, the comics in the collection showcase the courage and determination of workers who fought to bring about a better world. " -- Editor's website

    Relationships between Atlantic Puffin breeding success and annual mean mass of fish loads delivered to chicks.

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    <p>A. Values of annual adult Atlantic Puffin breeding success and annual mean mass of fish loads delivered to chicks in the same year during 1987 to 2013 plotted against each other without de-trending and B. plot of de-trended residuals. Lines represent fitted linear regressions (solid line = significant positive correlation, stippled line = weak positive correlation, non-significant).</p

    Atlantic Puffin survival and resighting probability estimates.

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    <p>A. Mean estimated adult Atlantic Puffin apparent survival probability (φ) and B. resighting probability (p) during 1987 to 2012. Estimates of φ and p are from models with random year effects on φ and p (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131527#pone.0131527.t001" target="_blank">Table 1</a> and see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131527#sec002" target="_blank">Methods</a>). Dashed lines represent ± 95% confidence intervals.</p
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