| 1. |
- Barboutis, Christos, et al.
(författare)
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From Mediterranean to Scandinavia – timing and body mass condition in four long distance migrants
- 2015
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Ingår i: Ornis Svecica. - 1102-6812 .- 2003-2633. ; 25, s. 51-58
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Tidskriftsartikel (refereegranskat)abstract
- In spring, long-distance migrants are considered to adopta time-minimizing strategy to promote early arrival atbreeding sites. The phenology of spring migration wasexamined and compared between two insular stopoversites in Greece and Sweden for Icterine Warbler, WoodWarbler, Spotted Flycatcher and Collared Flycatcher. All of them migrate due north which means that some proportion of birds that pass through Greece are headingto Scandinavia. The Collared Flycatcher had the earliestand the Icterine Warbler the latest arrival time. Thedifferences in median dates between Greece and Swedenwere 3–4 weeks and the passages in Sweden weregenerally more condensed in time. The average overallspeed estimates were very similar and varied between129 and 137 km/d. In most of the species higher speedestimates were associated with years when birds arrivedlate in Greece. After crossing continental Europe birdsarrive at the Swedish study site with significantly higherbody masses compared to when they arrive in Greece andthis might indicate a preparation for arriving at breedinggrounds with some overload.
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| 2. |
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| 3. |
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| 4. |
- Fransson, Thord, et al.
(författare)
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Svensk ringmärkning 2014
- 2015
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Ingår i: Fågelåret 2014. - Halmstad : Sveriges Ornitologiska Förening. ; Suppl:55, s. 25-31
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 5. |
- Fransson, Thord, et al.
(författare)
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Svensk ringmärkning 2015
- 2016
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Ingår i: Fågelåret 2015. - Halmstad : BirdLife Sverige - Sveriges Ornitologiska Förening. - 9789188124616 ; , s. 23-31
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Bokkapitel (populärvet., debatt m.m.)
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| 6. |
- Fransson, Thord, et al.
(författare)
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Svensk ringmärkning 2016
- 2016
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Ingår i: Fågelåret 2016. - Halmstad : BirdLife Sverige - Sveriges Ornitologiska Förening. - 9789188124630 ; , s. 23-31
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Bokkapitel (populärvet., debatt m.m.)
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| 7. |
- Fransson, Thord, et al.
(författare)
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Svensk ringmärkning 2017
- 2018
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Ingår i: Fågelåret 2017. - Halmstad : BirdLife Sverige - Sveriges Ornitologiska Förening. - 9789188124654 ; , s. 25-32
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Bokkapitel (populärvet., debatt m.m.)
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| 8. |
- Fransson, Thord, et al.
(författare)
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Svensk ringmärkning 2018
- 2019
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Ingår i: Fågfelåret 2018. - Halmstad : Sveriges Ornitologiska Förening - Birdlife Sverige 2019. - 9789188124661 ; , s. 25-33
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Bokkapitel (populärvet., debatt m.m.)
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| 9. |
- Hedlund, Johanna, 1982-
(författare)
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Climate change effects on migratory birds and on the ecology and behaviour of the willow warbler (Phylloscopus trochilus)
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Recent global climate change is influencing the behaviour and ecology of species worldwide. Birds are typical systems to study in this context, as they are often migratory and thus subjected to a variety of environmental effects. This thesis employs the use of long-term ringing records, field observations, historical maps and historical volunteer observations with the aim of describing behavioural and ecological responses of birds to the current environmental change. An investigation into the spring arrival, reproduction and autumn departure in willow warblers (Phylloscopus trochilus) breeding at a southern study site in Sweden (65°N 18°E) showed that all three phenological events had advanced in parallel. Thus birds arrive earlier, start breeding earlier and leave Sweden earlier, with the breeding period staying the same in length. By teasing apart the migratory responses of different individuals, it became clear that particularly early arriving males and early departing juveniles had advanced migration. However, willow warblers migrating past a northern study site in Sweden (65°N 23°E) displayed no change in autumn departure. When migration in the two regionally separate populations were analyzed in relation to climatic variables, the results indicated that foremost a combined effect of growing season onset and the North Atlantic Oscillation influenced migratory timing, and only in individuals that had advanced migration. As growing season onset had advanced at both regions, but only elicited migratory change in southern willow warblers, it is proposed that intra-specific difference between populations prepare them differently to climate change. Willow warblers breeding at northern latitudes were also displaying absence of an otherwise common behaviour of the species: philopatry. It is suggested that the climate induced change in onset of the growing season, coupled with an increase in available territories, could have enabled a southern influx of dispersal-prone birds adopting a less philopatric breeding behaviour. Availability of territories was also studied in southern Sweden, in relation to 100 years of land use change and future climate change effects on forestry. The mass-conversion of grazed forest into coniferous sylvicultures that has occurred in Sweden 1900-2013 was shown to have negatively affected territory availability for willow warblers. The second most common bird species in Sweden, the chaffinch (Fringilla coelebs), was however shown to be largely unaffected. In a future scenario where rising temperatures will increase growth rates of trees, harvest rotation will be faster and both sylvicultures and logged areas will increase in coverage, favouring both species. Thus commonness in terms of landscape and species occurrence has altered historically and is dynamically linked. Historic perspectives were also applied to observations of spring arrival of 14 migratory bird species. A relative comparison of two data sets, collected over 140 years, revealed that short-distance migrants have changed their spring arrival more than long-distance migrants in southern Sweden. In conclusion, the results of this thesis provide insights into climate change effects on avian behaviour and ecology, document unique observations and contribute with a great spectrum of knowledge, from exact details on responses by individual birds, through long-term changes in populations to historical perspectives on shifts in entire landscapes
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| 10. |
- Hedlund, Johanna S. U., et al.
(författare)
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Long-term phenological shifts and intra-specific differences in migratory change in the willow warbler Phylloscopus trochilus
- 2015
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 46:1, s. 97-106
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Tidskriftsartikel (refereegranskat)abstract
- Climate change can influence many aspects of avian phenology and especially migratory shifts and changes in breeding onset receive much research interest in this context. However, changes in these different life-cycle events in birds are often investigated separately and by means of ringing records of mixed populations. In this long-term study on the willow warbler Phylloscopus trochilus, we investigated timing of spring and autumn migration in conjunction with timing of breeding. We made distinction among individuals with regard to age, sex, juvenile origin and migratory phase. The data set comprised 22-yr of ringing records and two temporally separated data sets of egg-laying dates and arrival of the breeding population close to the ringing site. The results reveal an overall advancement consistent in most, but not all, phenological events. During spring migration, early and median passage of males and females became earlier by between 4.4 to 6.3 d and median egg-laying dates became earlier by 5 d. Male arrival advanced more, which may lead to an increase in the degree of protandry in the future. Among breeding individuals, only female arrival advanced in timing. In autumn, adults and locally hatched juvenile females did not advanced median passage, but locally hatched juvenile males appeared 4.2 d earlier. Migrating juvenile males and females advanced passage both in early and median migratory phase by between 8.4 to 10.1 d. The dissimilarities in the response between birds of different age, sex and migratory phase emphasize that environmental change may elicit intra-specific selection pressures. The overall consistency of the phenological change in spring, autumn and egg-laying, coupled with the unchanged number of days between median spring and autumn migration in adults, indicate that the breeding area residence has advanced seasonally but remained temporally constant.
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