scholarly journals Autumn migration strategy of juvenile great reed warblers Acrocephalus arundinaceus on the eastern European flyway: a spatiotemporal pattern of accumulation and utilisation of energy stores

2020 ◽  
Vol 87 (1) ◽  
pp. 537-551
Author(s):  
K. Stępniewska ◽  
A. Ożarowska ◽  
P. Busse ◽  
R. Bobrek ◽  
P. Zehtindjiev ◽  
...  
2020 ◽  
Vol 16 (6) ◽  
pp. 20200155
Author(s):  
Claudie Pageau ◽  
Christopher M. Tonra ◽  
Mateen Shaikh ◽  
Nancy J. Flood ◽  
Matthew W. Reudink

To avoid energy allocation conflicts, birds generally separate breeding, migration and moult during the annual cycle. North American passerines typically moult on the breeding grounds prior to autumn migration. However, some have evolved a moult-migration strategy in which they delay moult until stopping over during autumn migration. Rohwer et al . (2005) proposed the ‘push–pull hypothesis' as an explanation for the evolution of this moult strategy, but it has not been empirically tested. Poor conditions on the breeding grounds at the end of the summer would push birds to depart prior to moult, while productive stopover locations would pull them. We tested for a relationship between moult-migration and breeding grounds aridity as measured by the normalized difference vegetation index. Our results strongly support the ‘push' aspect of the push–pull hypothesis and indicate that arid breeding grounds, primarily in western North America, would drive species to evolve stopover moult-migration, although this relationship may depend upon migration distance.


2010 ◽  
Vol 45 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Piotr Minias ◽  
Krzysztof Kaczmarek ◽  
Radosław Włodarczyk ◽  
Tomasz Janiszewski

2016 ◽  
Vol 12 (4) ◽  
pp. 20151060 ◽  
Author(s):  
Janne Ouwehand ◽  
Christiaan Both

Each year more than two billion songbirds cross the Sahara, but how they perform this formidable task is largely unknown. Using geolocation tracks from 27 pied flycatchers, a nocturnally migrating passerine, we show that most birds made diurnal flights in both autumn and spring. These diurnal flights were estimated to be part of non-stop flights of mostly 40–60 h. In spring, birds flew across the Sahara, while autumn migration probably circumpassed part of the desert, through a long oversea flight. Our data contradict claims that passerines cross the Sahara by intermittent flight and daytime resting. The frequent occurrence of long non-stop flights to cross the desert shows migrants' physiological abilities and poses the question why this would not be the general migration strategy to cross the Sahara.


2019 ◽  
Vol 28 (2) ◽  
pp. 501-514
Author(s):  
Deborah A. Hwa-Froelich ◽  
Hisako Matsuo

Purpose Pragmatic language is important for social communication across all settings. Children adopted internationally (CAI) may be at risk of poorer pragmatic language because of adverse early care, delayed adopted language development, and less ability to inhibit. The purpose of this study was to compare pragmatic language performance of CAI from Asian and Eastern European countries with a nonadopted group of children who were of the same age and from similar socioeconomic backgrounds as well as explore the relationship among emotion identification, false belief understanding, and inhibition variables with pragmatic language performance. Method Using a quasi-experimental design, 35 four-year-old CAI (20 Asian, 15 Eastern European) and 33 children who were not adopted were included in this study. The children's pragmatic language, general language, and social communication (emotion identification of facial expressions, false belief understanding, inhibition) were measured. Comparisons by region of origin and adoption experience were completed. We conducted split-half correlation analyses and entered significant correlation variables into simple and backward regression models. Results Pragmatic language performance differed by adoption experience. The adopted and nonadopted groups demonstrated different correlation patterns. Language performance explained most of the pragmatic language variance. Discussion Because CAI perform less well than their nonadopted peers on pragmatic communication measures and different variables are related to their pragmatic performance, speech-language pathologists may need to adapt assessment and intervention practices for this population.


Author(s):  
Johann P. Arnason

Different understandings of European integration, its background and present problems are represented in this book, but they share an emphasis on historical processes, geopolitical dynamics and regional diversity. The introduction surveys approaches to the question of European continuities and discontinuities, before going on to an overview of chapters. The following three contributions deal with long-term perspectives, including the question of Europe as a civilisational entity, the civilisational crisis of the twentieth century, marked by wars and totalitarian regimes, and a comparison of the European Union with the Habsburg Empire, with particular emphasis on similar crisis symptoms. The next three chapters discuss various aspects and contexts of the present crisis. Reflections on the Brexit controversy throw light on a longer history of intra-Union rivalry, enduring disputes and changing external conditions. An analysis of efforts to strengthen the EU’s legal and constitutional framework, and of resistances to them, highlights the unfinished agenda of integration. A closer look at the much-disputed Islamic presence in Europe suggests that an interdependent radicalization of Islamism and the European extreme right is a major factor in current political developments. Three concluding chapters adopt specific regional perspectives. Central and Eastern European countries, especially Poland, are following a path that leads to conflicts with dominant orientations of the EU, but this also raises questions about Europe’s future. The record of Scandinavian policies in relation to Europe exemplifies more general problems faced by peripheral regions. Finally, growing dissonances and divergences within the EU may strengthen the case for Eurasian perspectives.


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