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

Migration direction in a songbird explained by two loci

Migratory routes and remote wintering quarters in birds are often species and even population specific. It has been known for decades that songbirds mainly migrate solitarily, and that the migration direction is genetically controlled. Yet, the underlying genetic mechanisms remain unknown. To investigate the genetic basis of migration direction, we track genotyped willow warblers Phylloscopus trochilus from a migratory divide in Sweden, where South-West migrating, and South-East migrating subspecies form a hybrid swarm. We find evidence that migration direction follows a dominant inheritance pattern with epistatic interaction between two loci explaining 74% of variation. Consequently, most hybrids migrate similarly to one of the parental subspecies, and therefore do not suffer from the cost of following an inferior, intermediate route. This has significant implications for understanding the selection processes that maintain narrow migratory divides

Multiple fragmented habitat-patch use in an urban breeding passerine, the Short-toed Treecreeper

Individual responses of wild birds to fragmented habitat have rarely been studied, despite large-scale habitat fragmentation and biodiversity loss resulting from widespread urbanisation. We investigated the spatial ecology of the Short-toed Treecreeper Certhia brachydactyla, a tiny, resident, woodland passerine that has recently colonised city parks at the northern extent of its range. High resolution spatiotemporal movements of this obligate tree-living species were determined using radio telemetry within the urbanized matrix of city parks in Copenhagen, Denmark. We identified regular edge crossing behaviour, novel in woodland birds. While low numbers of individuals precluded a comprehensive characterisation of home range for this population, we were able to describe a consistent behaviour which has consequences for our understanding of animal movement in urban ecosystems. We report that treecreepers move freely, and apparently do so regularly, between isolated habitat patches. This behaviour is a possible driver of the range expansion in this species and may contribute to rapid dispersal capabilities in certain avian species, including Short-toed Treecreepers, into northern Europe. Alternatively, these behaviours might be common and/or provide an adaptive advantage for birds utilising matrix habitats, for example within urban ecosystems

A különleges szakiskolák

Additional file 1. Supplementary information on European nightjars. Data on individual birds (Table S1), stopover duration (Table S2) and definition of high-quality positions (Fig. S1)

Resource tracking within and across continents in long-distance bird migrants

Migratory birds track seasonal resources across and between continents. We propose a general strategy of tracking the broad seasonal abundance of resources throughout the annual cycle in the longest-distance migrating land birds as an alternative to tracking a certain climatic niche or shorter-term resource surplus occurring, for example, during spring foliation. Whether and how this is possible for complex annual spatiotemporal schedules is not known. New tracking technology enables unprecedented spatial and temporal mapping of long-distance movement of birds. We show that three Palearctic-African species track vegetation greenness throughout their annual cycle, adjusting the timing and direction of migratory movements with seasonal changes in resource availability over Europe and Africa. Common cuckoos maximize the vegetation greenness, whereas red-backed shrikes and thrush nightingales track seasonal surplus in greenness. Our results demonstrate that the longest-distance migrants move between consecutive staging areas even within the wintering region in Africa to match seasonal variation in regional climate. End-of-century climate projections indicate that optimizing greenness would be possible but that vegetation surplus might be more difficult to track in the future

Spatial behavior and habitat use in widely separated breeding and wintering distributions across three species of long-distance migrant <i>Phylloscopus</i> warblers

Aim: To investigate the ecological relationship between breeding and wintering in specialist and generalist long-distance migratory species, and the links between densities and range sizes. Location: Denmark, Senegal and Ghana. Methods: We use radio tracking to study spatial behavior and habitat use in three morphologically and ecologically similar and closely related Phylloscopus species on their widely separated breeding and wintering distributions. During wintering and breeding, willow warblers P. trochilus (winter: n = 9, breeding: n = 13), chiffchaffs P. collybita (n = 11, n = 7), and wood warblers P. sibilatrix (n = 17, n = 14) were tracked. Results: Willow warblers P. trochilus increased home range sizes in winter, whereas it was similar in chiffchaffs P. collybita and wood warblers P. sibilatrix, in both seasons. Home ranges overlapped more in winter than in the breeding season. In winter, home range overlap was similar among species but larger overlap during breeding was indicated for willow warblers. Tree cover was unrelated to home range size but significantly higher in breeding than in winter in all species. However, whereas willow warblers and wood warblers maintained some degree of tall tree cover inside their home ranges in winter, chiffchaffs changed from more than 80% to <1% tree cover, indicating a niche shift. Main conclusions: Individuals of all three species showed changes between breeding and wintering areas in spatial behavior and habitat availability, with larger overlap in winter. The differences in patterns were potentially related to being generalist (willow warbler) or specialist (chiffchaff and wood warbler). These ecological relationships are important for the conservation of migrants and for understanding the link between breeding and wintering distributions and ecology

Remarkably similar migration patterns between different red-backed shrike populations suggest that migration rather than breeding area phenology determines the annual cycle

The regular fluctuation of resources across the Globe guides movements of migratory animals. To ensure sufficient reproductive output and maintain viable population sizes, migratory animals should match arrival at breeding areas with local peaks in resource availability. It is generally assumed that breeding phenology dictates the timing of the annual cycle, but this is poorly studied. Here, we use light-level geolocator tracking data to compare the annual spatiotemporal migration patterns of a long-distance migratory songbird, the red-backed shrike, Lanius collurio, breeding at widely different latitudes within Europe. We find that populations use remarkably similar migration routes and are highly synchronized in time. Additional tracks from populations breeding at the edges of the European range support these similar migration patterns. When comparing timing of breeding and vegetation phenology, as a measure of resource availability across populations, we find that arrival and timing of breeding corresponds to the peak in vegetation greenness at northern latitudes. At lower latitudes birds arrive simultaneously with the more northerly breeding populations, but after the local greenness peak, suggesting that breeding area phenology does not determine the migratory schedule. Rather, timing of migration in red-backed shrikes may be constrained by events in other parts of the annual cycle.</p

First-Time Migration in Juvenile Common Cuckoos Documented by Satellite Tracking

Being an obligate parasite, juvenile common cuckoos Cuculus canorus are thought to reachtheir African wintering grounds from Palearctic breeding grounds without guidance fromexperienced conspecifics but this has not been documented. We used satellite tracking tostudy naïve migrating common cuckoos. Juvenile cuckoos left breeding sites in Finlandmoving slowly and less consistently directed than adult cuckoos. Migration of the juveniles(N = 5) was initiated later than adults (N = 20), was directed toward the southwest±significantlydifferent from the initial southeast direction of adults±and included strikingly long BalticSea crossings (N = 3). After initial migration of juvenile cuckoos toward Poland, themigration direction changed and proceeded due south, directly toward the winter grounds,as revealed by a single tag transmitting until arrival in Northwest Angola where northernadult cuckoos regularly winter. Compared to adults, the juvenile travelled straighter andfaster, potentially correcting for wind drift along the route. That both migration route and timingdiffered from adults indicates that juvenile cuckoos are able to reach proper winteringgrounds independently, guided only by their innate migration programme.</p

Using geolocator tracking data and ringing archives to validate citizen-science based seasonal predictions of bird distribution in a data-poor region

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