Migration of the Common Redstart (<em>Phoenicurus phoenicurus)</em>:a Eurasian songbird wintering in highly seasonal conditions in the West African Sahel

Some species of long-distance migrant birds are thought to follow spatiotemporal patterns of high food availability during the non-breeding season, a strategy termed "itinerancy," instead of being sedentary in one specific site. We tracked the migration of a small Eurasian songbird, the Common Redstart (Phoenicurus phoenicurus), using archival light-level geolocators. The birds showed a distinct counterclockwise loop migration from northern Europe. Fall migration passed west of the Mediterranean Sea and along the northwest African coast before the birds made an abrupt change of direction at the southern edge of the Sahara toward the winter area farther inland in the West African Sahel. Spring migration was more direct: north to the Iberian Peninsula and back to northern Europe. The birds spent more time in only one winter site than they do during the breeding season in northern Europe, and they generally showed no signs of itinerancy-except for one bird that probably avoided an exceptional drought. Their arrival on the winter grounds was well timed with peak vegetation greenness, assumed to reflect food availability, but vegetation greenness declined rapidly during their stay, and resource availability was relatively low throughout most of the non-breeding season. Despite the highly seasonal conditions in the wintering area, itinerancy is apparently not an optimal strategy for the Common Redstart, possibly because of timing constraints. Alternatively, food availability may not be closely linked to vegetation greenness

Prey diversity is affected by climate and differs between age classes in the Red-backed Shrike (Lanius collurio)

When breeding, food availability is essential for optimal reproductive output and is po-tentially one of the main factors limiting breeding success, especially in single brooded long-distance migratory birds. In this study, we examined the diet (as a measure of prey availability) of two Red-backed Shrike (Lanius collurio) populations in Denmark, based on more than 11,000 prey items covering seven years. We found a negative correlation be-tween prey diversity and temperature, indicating that Red-backed Shrikes feed on pre-ferred prey items in warmer summers (low diversity) while forced to feed on a larger vari-ety of species in colder summers. Adults had a more diverse diet and generally fed on smaller prey items than did young birds. Thus, age-and environment-related differences must be taken into account when describing the diet of the Red-backed Shrike. Direct nest observations produced different results for diet composition than did nest and pellet samples, underlining the importance of using different methods in diet assessments. De-tailed knowledge on limiting factors on the breeding grounds, such as food availability, is crucial for mitigating population declines of vulnerable species, such as the Red-backed Shrike

Autumn migration and wintering site of a wood warbler Phylloscopus sibilatrix breeding in Denmark identified using geolocation

Abstract Background Basic knowledge of detailed spatiotemporal migration patterns is lacking for most migratory bird species. Using the smallest available geolocator, we aim to map autumn migration and wintering areas of north European wood warblers Phylloscopus sibilatrix and compare the spatiotemporal pattern with recoveries of individuals ringed across Europe. Results A tracked wood warbler migrated south-south-east to sub-Saharan Africa in Sudan and then west-south-west to winter in Côte d’Ivoire. The timing and route fits well within the distribution of ring recoveries although the westward movement after the Sahara crossing is not revealed by the ring recoveries, but only few recoveries south of Sahara exist. Conclusions The surprising westward movement south of the Sahara supplements the overall pattern revealed by ring recoveries and aids our understanding of the connectivity and site dependence in this generally declining species

Patterns of phenological changes in migratory birds

Abstract The phenology of avian migration appears to be changing in response to climate change. Seemingly contradictory diVerences in the timing of these annual cycles have been reported in published studies. We show that diVerences between studies in the choice of songbird species, as well as in the measurements of migration phenology, can explain most of the reported diVerences. Furthermore, while earlier spring arrival is evident across these studies, trends in timing of departure show large variation between species and according to individual timing of migration (early-arriving vs. late-departing individuals). Much of the variation in departure between species could be explained by each species&apos; migratory status. We present a detailed analysis of migrants recorded at a Danish migration site, and reveal that although shifts in migration timing can be demonstrated for almost all species, these shifts are either most pronounced in the early arriving/late departing individuals or the changes are similar. Thus most individuals do not seem to change their breedingarea residence time (BART). As BART is likely to reXect ecologically important factors, e.g. number of clutches, we expect that only small eVects have been exerted on the breeding ecology of the studied species in the time period investigated

Questioning Development Orthodoxy

This paper traces the history and current state of international economic development through its institutions and attempts to reassess these institutions and their processes in a heterodox manner. There are many stereotypes and clichés to the foreign assistance industry: that it takes from the poor in rich countries and gives to the rich in poor countries; that it provides laboratories for economists and other social scientists to apply theories abroad that they would never attempt at home (the most obvious examples of these are population control programs and the privatization of pension funds); and that development creates “brain drain” from indigenous 2 institutions to the very institutions of development itself. Although a brief summary of the major research programs in development is given, the paper does not attempt to falsify or confirm any of these or other research programs and their corresponding policy recommendations. The purpose of the paper is to question the very nature of international economic development itself through an historical and philosophical re-examination of its institutional constructs. The Hegelian dialectical method of analysis is applied to the institutions of economic development and is used to ask, “what next and why

Activity and migratory flights of individual free-flying songbirds throughout the annual cycle:method and first case study

We describe a method and device ( 66 (max. 73) nocturnal migratory flights (29 flights in autumn and > 37, max. 44, in spring) adding up to a total of > 434 (max. 495) flight hours. Migratory flights lasted on average 6.6 h with maximum 15.9 h. These flights were aggregated into eight travel episodes (periods of 4-11 nights when flights took place on the majority of nights). Daytime resting levels were much higher during the winter period compared to breeding and final part of spring migration. Daytime resting showed peaks during days between successive nocturnal flights across Sahara, continental Africa and the Arabian Peninsula, indicating that the bird was mostly sleeping between these long migratory flights. Annual activity and flight data for free-living songbirds will open up many new research possibilities. Main topics that can be addressed are e.g. migratory flight performance (total flight investment, numbers and characteristics of flights), timing of stationary periods, activity patterns (resting/sleep, activity level) in different phases of the annual cycle and variability in the annual activity patterns between and within individuals

Dataset on species incidence, species richness and forest characteristics in a Danish protected area

The data presented in this article are related to the research article entitled “Restoring hydrology and old-growth structures in a former production forest: Modelling the long-term effects on biodiversity” (A. Mazziotta, J. Heilmann-Clausen, H. H.Bruun, Ö. Fritz, E. Aude, A.P. Tøttrup) [1]. This article describes how the changes induced by restoration actions in forest hydrology and structure alter the biodiversity value of a Danish forest reserve. The field dataset is made publicly available to enable critical or extended analyses