IBIS | Volume 158 | Issue 3 | July 2016
The latest issue of IBIS features 16 full papers and one short communication. It also contains citations for Chris Perrins on his award of the Union Medal and Tim Birkhead on his award of the Godman-Salvin Prize, plus our usual extensive book review section.
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Here are just a few of the many highlights.
Survival of Afro-Palaearctic passerine migrants in western Europe and the impacts of seasonal weather variables
Alison Johnston, Robert A. Robinson, Gabriel Gargallo, Romain Julliard, Henk van der Jeugd & Stephen R. Baillie
The widespread declines in the populations of Afro-Palaearctic migrant songbirds is one of the most pressing issues in European bird conservation today, yet the reasons for these declines remain very unclear. It is not even clear whether the problems lie on the breeding grounds in Europe, on the wintering grounds in Africa or somewhere along the migration routes in between. Using data from constant-effort ringing schemes, Alison Johnston of the British Trust for Ornithology and her colleagues assess the relationship between survival rates, population trends and weather. They find that species wintering in humid areas of western Africa have had significantly higher annual survival probabilities than species wintering in the arid the Sahel. Rainfall in the Sahel was positively correlated with survival in at least some populations of five species. Importantly, the authors were able to demonstrate a link between annual survival and population trend, suggesting that although the precise mechanism of these declines remain elusive, they appear to act more on survival than on productivity. This is an important step forward in identifying the â€œsmoking gunâ€ that is causing migrant populations to fall across Europe.
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Temperate migrants and resident bird species in Afro-tropical savannahs show similar levels of ecological generalism
Sam T. Ivande & Will Cresswell
Staying on the subject of declining Afro-Palaearctic migrant birds, Sam Ivande and Will Cresswell, both of St Andrews University and the A.P. Leventis Ornithological Research Institute (APLORI) in Nigeria, approach the problem from a different angle by assessing the likely vulnerability of wintering migrants to habitat change or loss relative to resident African species. They argue that if Afro-Palaearctic migrant birds wintering in Africa are highly habitat specific, their declines might more easily be explained by anthropogenic changes in the environment, whereas if they are able to exploit a broad range of habitats, they are better able to withstand such changes, in which case other factors are more likely to be driving their declines. By looking at how species occur over a range of habitat gradients, the authors show that wintering migrants are no more specialised or generalised than are ecologically and taxonomically similar resident African species. This suggests that wintering migrants are unlikely to be limited by the availability of, or changes in, specific habitat types in their African wintering areas and so should be fairly robust to habitat change. Taken together, this and the previous paper suggest that researchers may need to look in more detail at survival and habitat use along the migration routes of these declining species.
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The phylogenetic relationships of Przevalski's Finch Urocynchramus pylzowi, the most ancient Tibetan endemic passerine known to date
Martin PÃ¤kert, Jochen Martens, Yue-Hua Sun & Patrick Strutzenberger
Przevalskiâ€™s Finch has puzzled taxonomists for many years, as its plethora of alternative names (Pink-tailed Bunting, Pink-tailed Rosefinch) attests. Superficially like a rosefinch, the species has a range of vocalisations and egg colouration unlike any similar species, but it has traditionally been placed with the Old World buntings (Emberizidae) or with the carduelline finches (Fringillidae, Carduelinae). Now Martin PÃ¤kert of the Senckenberg Natural History Collections in Dresden and colleagues present the most detailed genetic analysis of this strange species yet undertaken. Their results suggest that traditional placements were wrong, and that far from being a bunting or a carduelline finch, U. pylzowi is actually part of the clade formed by weavers and waxbills. Within this clade, it appears closest to the ploceid weavers, but is still sufficiently different in a number of ways to be treated as a separate group within this clade. Remarkably, it appears to have diverged from its nearest ancestors as much as 25 million years ago, making this the most ancient songbird yet recorded from the Tibetan region.
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Negative impact of wind energy development on a breeding shorebird assessed with a BACI study design
Alex Sansom, James W. Pearce-Higgins & David J. T. Douglas
The proliferation of alternative energy production has raised fears that, despite the reduction in greenhouse gasses, infrastructure such as wind turbines can have direct and indirect negative impacts on birds and other wildlife. However, most assessments of the environmental impacts of wind farms are hampered by a lack of comparative data. The RSPBâ€™s Alex Sansom and her colleagues present one of the first fully controlled â€˜before-after-control-interventionâ€™ (BACI) studies of the impacts of wind farms and birds, comparing densities of Golden Plovers Pluvialis apricaria before, during and after wind farm construction, both at the wind farm and at a control site. They find that while Golden Plover densities were unaffected by the construction of the wind farm, they were very significantly lower once the farm began to operate, with a decline of nearly 80% in density and a displacement of birds by up to 400 metres. As no comparable changes were observed in the buffer or control zones, the authors conclude that the observed declines are a direct, and probably behavioural, response to the presence of the turbines. However, breeding success was unaffected. This has considerable implication for the future placement of wind farms.
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