| 1. |
- Rydell, Jens, et al.
(författare)
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Bat mortality at wind turbines in northwestern Europe
- 2010
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Ingår i: Acta Chiropterologica. - 1508-1109. ; 12:2, s. 261-274
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Tidskriftsartikel (refereegranskat)abstract
- We reviewed published and unpublished written reports on bat mortality at wind farms in northwestern Europe. The estimated number of bats killed per turbine annually was relatively low (0-3) on flat, open farmland away from the coast, higher (2-5) in more complex agricultural landscapes, and highest (5-20) at the coast and on forested hills and ridges. The species killed almost exclusively (98%) belonged to a group (Nyctalus, Pipistrellus, Vespertilio and Eptesicus spp.) adapted for open-air foraging. The bats were killed by the moving rotor blades as they hunted insects attracted to the turbines. This occurred independently of sex and age. Peak mortality varied considerably in frequency and timing among years, but the events usually (90%) occurred on nights with low wind speeds in late July to early October and to a lesser extent (10%) also in April-June. The mortality increased with turbine tower height and rotor diameter but was independent of the distance from the ground to the lowest rotor point. It was also independent of the size of the wind park (1-18 turbines). Bat species other than the open-air suite referred to above are usually not at risk at wind turbines, because they fly below the rotors, but are still killed occasionally (2%).
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| 2. |
- Green, Martin, et al.
(författare)
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Häckande fåglar i Värmlands län : Trender för arter samt miljöindikatorer baserade på standardrutter och nattrutter
- 2020
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Rapport (populärvet., debatt m.m.)abstract
- Systemet med systematiskt utlagda standardrutter utgör ryggraden i den generella nationella och regionala miljöövervakningen av fåglar. I Värmlands län återfinns 34 av landets 716 standardrutter (knappt 5 %). I denna rapport redovisas utvecklingen för länets generella fågelfauna under perioden 1998–2019, även om vi också redovisar trender för perioderna 2002–2019 och 2010–2019. Den förstnämnda perioden är den längsta möjliga som vi kan beräkna trender för. Trenderna från 2002 och framåt täcker den period när vi har bättre årlig regional täckning generellt i landet. Den avslutande perioden täcker de senaste tio åren och används för att visa hur det går just nu, eller snarare hur det har gått i det allra senaste.Under 2010-talet har täckningen av länets standardrutter varit mycket god och motsvarande 62–100 % (medel 81 %) av de regionala rutterna har inventerats årligen. Detta är en lämplig fortsatt ambitionsnivå för att kunna ha en god övervakning av länets allmänna fåglar. Den goda täckningen av länet är helt beroende av att Länsstyrelsen och Naturvårdsverket finansierar fältinsatserna. Ungefär hälften av den årliga inventeringsinsatsen i länet bekostas av Länsstyrelsen och den andra hälften direkt av centrala anslag från Naturvårdsverket.Med startår 1998 är det 79 arter som setts näst intill årligen (minst 20 av 22 år) på länets standardrutter. Av dessa ökade 19 arter (24 %) och minskade 15 arter (19 %) säkert i antal. 25 arter (32 %) uppvisade stabila bestånd och för 20 arter (25 %) var utvecklingen osäker. Sett enbart till trendernas riktning, oavsett statistisk säkerhet, var det en övervikt (61 %) för arter med positiv trendriktning.Från 2002 är det 87 arter som bokförts på Värmlands standardrutter under nästan alla år (minst 16 av 18 år). Från detta startår var det övergripande mönstret mera negativt; bara sex arter (7 %) ökade medan 15 (17 %) minskade säkert i antal. 25 arter (29 %) hade stabila bestånd och för 41 arter (47 %) var utvecklingen osäker. Om vi enbart ser till trendriktningarna, oavsett statistisk säkerhet, var det under denna period en övervikt (62 %) för negativa trendriktningar, vilket förstärker bilden av ett mer negativt mönster från 2002–2019 än 1998–2019.De senaste tio åren (2010–2019) har 105 arter setts nära nog årligen (minst åtta av tio år) på standardrutterna i Värmlands län. Under denna korta period har pendeln svängt tillbaka åt det positiva hållet igen. I korttidsperspektivet är det 19 arter (18 %) som uppvisar säkra ökningar och blott två arter (2 %) med säkra minskningar. Sex arter (6 %) har haft stabila bestånd de senaste tio åren och för 78 arter (74 %) är beståndsutvecklingen osäker under denna period. Här måste en komma ihåg att den korta tidsperioden gör det svårare att få fram statistiskt säkra resultat. Därmed är det ofrånkomligt att andelen osäkra resultat är hög. Återigen var det nu en övervikt (64 %) av positiva trendriktningar om vi bortser från statistisk säkerhet och enbart tittar på själva riktningarna. Sedan 2011 har 17 olika nattrutter inventerats i Värmlands län, men det är enbart de fyra senaste åren, 2016–2019, som ett högre antal nattrutter har inventerats årligen. Detta tack vare Länsstyrelsens engagemang med att hitta lokala inventerare till länets nattrutter. Under dessa år har 12–16 rutter (medel 14) inventerats per år. Det är därför för denna väldigt korta period som vi redovisar lite mer detaljerade nattruttsresultat. Baserat på nattruttsdata presenterar vi utvecklingen för 33 utvalda fågel- och elva däggdjursarter som noterats på rutterna under minst två av de senaste fyra åren. Här ingår exempelvis sju olika ugglearter. Inga djupare slutsatser ska såklart dras från en så kort period som enbart fyra år, men vi kan konstatera att fyra ugglearter har bokförts årligen i länet. Dessa är katt-, slag-, horn- och pärluggla. För kattuggla är Värmlands län ett av de som hittills uppvisat de högsta noterade antalen per rutt. Vi kan också konstatera 2017 av allt att döma var ett gott gnagarår med goda registrerade uggleantal. En annan intressant nattaktiv fågelart är nattskärran, och precis som i landet i stort förefaller det gå bra för den arten i Värmland just nu. Flertalet bokförda däggdjursarter uppvisar positiva mönster på länets nattrutter under de senaste fyra åren.Indikatorer, gemensamma trender för grupper av fåglar, visar generellt sett på få statistiskt säkra förändringar i Värmlands län under perioden 2002–2019. I skogen finns tecken på en positiv utveckling, mest så under de allra senaste tio åren, men utan statistisk säkerhet. Mest positiv är till synes utvecklingen för fågelarter knutna till äldre skog. Även om statistiskt säkra resultat saknas så antyder mönstren i Värmlands län en betydligt mer positiv regional utveckling än den som finns för landet som helhet.Indikatorerna för odlingslandskapet visar på säkra minskningar över hela perioden 2002–2019, precis som i landet i stort. De senaste tio åren finns inga säkra förändringar, men dock små tecken på en regional uppgång. Dessa tecken är klart starkare i Värmlands län än i Sverige totalt sett.När det gäller våtmarker uppvisar de regionala indikatorerna tydligt positiva mönster som dock inte är statistiskt säkerställda. Tydligast positiva är trenderna under de senaste tio åren. Utvecklingen i Värmlands län är till synes mer positiv än den i hela Sverige. För sjöar och vattendrag har läget varit stabilt sett över hela perioden 2002–2019. Ett svagt positivt mönster finns för de senaste tio åren. I hela Sverige finns en säker ökning i korttidsperspektivet.De två indikatorerna som kopplar till biologisk mångfald i stort ger delvis lite olika utfall för Värmlands län, även om skillnaderna egentligen inte är så stora. En ena visar på en säker minskning över hela perioden 2002–2019, vilken den andra inte gör. Bakom detta finns för båda ett negativt mönster för hela perioden och ett lite positivt sådant för de senaste tio åren. På en generell nivå stämmer detta med hur det ser upp på nationell nivå. Där finns en statistiskt säker minskning för hela perioden men en lika säker ökning de senaste tio åren.Indikatorn som kopplar till effekterna av klimatförändring visar att det värmländska fågelsamhället har blivit ”varmare” under de senaste 18 åren. Detta innebär arter med varmare utbredningsområden relativt sett har haft en mer positiv utveckling än arter med kallare utbredningsområden. Med andra ord kan vi redan nu se att den värmländska fågelfaunan förändrats i takt med ett allt varmare klimat.
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| 3. |
- Ram, Dafne, et al.
(författare)
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What drives current population trends in forest birds – forest quantity, quality or climate? A large-scale analysis from northern Europe
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 385, s. 177-188
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Tidskriftsartikel (refereegranskat)abstract
- Changes in forestry practices and on-going climate change may both have large impacts on forest bird populations. However, large-scale analyses of the effects of temporal changes in forest structure on forest bird numbers are largely lacking. We compared temporal trends from two Swedish nationwide long-term monitoring schemes, the Swedish Bird Survey (1998–2015) and the Swedish National Forestry Inventory (1983–2014), giving representative values for both forest and bird changes over an area of 35 million ha. Since 1998 the total area of middle-aged and mature forest increased by 6.4%. In parallel, several forest structures potentially beneficial to birds (dead wood, retention trees on clear cuts, multi-layer forests, old forest and broadleaved forest) increased somewhat in abundance, most likely as a result of legislation changes and increasing areas under forest certification schemes. Summer temperatures also increased, with warm summers dominating since 2002. In 1998–2015, the population sizes of 58 forest bird species on average increased, as did the number of species observed per route, with no general difference between forest specialists (16 species) and generalists (42 species). However, from around 2005, the positive trends in bird numbers and many forest structures have levelled out. An analysis of species population trends in relation to a measure of climate sensitivity (Species Temperature Index, STI) suggested that forest birds, just like Swedish birds in general, have indeed been affected by a warming climate. But given their STI, forest birds on average had more positive trends than non-forest birds, suggesting that other factors than climate have affected them positively. Strong candidate factors are the documented changes in forest quality and quantity. Whereas our data and analyses are correlational, and no firm conclusions on causality therefore can be drawn, it is reasonable to assume that the recent increases in forest quantity, forest quality, and summer temperatures, all have contributed to the general increase in forest bird numbers in Sweden. But the relative contribution of these driving forces remains to be determined. When it comes to the potentially positive effects of improving forest quality in terms of increases in old forest, stratification, retention trees and dead wood, it is noteworthy that many of the positive trends in forest structures since the mid-1990s seem to have ceased recently.
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| 4. |
- Andersson, G., et al.
(författare)
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Arthropod populations in a sub-arctic environment facing climate change over a half-century: variability but no general trend
- 2022
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 15:5, s. 534-542
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Tidskriftsartikel (refereegranskat)abstract
- Dramatic declines of some arthropod populations have recently received a lot of attention. Identified declines have mainly been attributed to changes in agriculture, climate, pathogen prevalence and light pollution, as well as cross-regional effects of, e.g., drifting pesticides. However, the overall picture is complex and debated, and there is a need for systematically collected long-term data, not least from areas relatively unaffected by humans. We monitored the abundance of arthropods (mainly insects) in subalpine birch forest in Swedish Lapland over a period of 53 years (1968-2020), in an area comparatively unaffected by human activities. Arthropod abundance was assessed by yearly systematic counts on 24,000 birch shoots, in the second half of June. Animals were categorised into 17 different groups directly upon counting, dependent on taxonomy and life stage (imago, larva). Overall, there was no significant change in arthropod numbers. Nor did estimates of the total biomass of arthropods (using group-specific indices of the mass of individuals) show any significant trend. Accordingly, there are no signs that the arthropod abundance or biomass on birch in this subarctic study site has gone through the same declines as have been reported from sites in other habitats. The reason may be that the impact of factors identified worldwide as drivers of arthropod declines so far are small or non-existent because of the low human population density in this area.
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| 5. |
- Green, Martin, et al.
(författare)
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Övervakning av fåglarnas populationsutveckling: : Årsrapport för 2022
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- We present the results of the Swedish Bird Survey, a project run by the Department of Biology, Lund University, as a part of the National Monitoring Programme of the Swedish Environmental Protection Agency. The results for 2022 include data from: 546 winter point counts in 2021/2022 (47th winter), ofwhich 254 were carried out during the Christmas/New Year count, 209 summer point count routes (48th year) and 375 Fixed routes (27th year). In the programme for covering night-active birds (13 th season), 155 routes were covered on up to three occasions each (March, April and June). In addition, 425waterbird routes (8th season) and 186 archipelago squares (8th season) were surveyed. In the waterbird counts included in the International Waterbird Census (IWC) 219 sectors were counted in September (49 th year) and 1084 sectors in January (57th year). In total 740 persons were involved in the surveysreported here.Population trends were analyzed using TRIM and trends for 224 different bird species are presented, as well as the geographical distributions of the covered routes. Larger mammals are counted on the Night routes and the Fixed routes since 2010 and 2011, respectively, and we present trends for 12 mammal species based on these two systems. We also present trends from the schemes of water- and archipelago birds, through which we can follow yet more species with systematic counts during the breeding period.The long-term trends show both winners and losers among the Swedish birds. The species with the strongest declines during the breeding season are Eurasian Wigeon, Common Pochard, Common Eider, Common Shelduck, Northern Lapwing, Eurasian Curlew, Common Sandpiper, Ruff, European Herring Gull, Common Swift, Common House and Sand Martin, Hooded Crow, Marsh and Willow Tit, Common Reed Warbler, Common Starling, Yellowhammer and Ortolan Bunting. The strongest increases are found in Great Cormorant, Gadwall, Grey-lag Goose, Whooper Swan, Red Kite, White-tailed Eagle, Western Marsh Harrier, Common Crane, Eurasian Blue Tit, Eurasian Blackcap, southern Common Chiffchaff and European Goldfinch.Based on 187 taxa recorded on the Fixed routes over the last 10 years, there are more species significantly increasing in numbers (29%), than decreasing in numbers (15%). For the remaining species (56%), no statistically significant changes were recorded during the last ten years. Eurasian Skylark and Common Linnet has increased strongly in the last decade following long-term declines.After a long period of relative stability, Barn Swallow has decreased markedly in numbers in recent years.Based on the winter point counts, also here there are more positive than negative trends for the last ten years. In total 27% of 114 species have increased significantly, while 19% have decreased. For waterbirds specifically and based on the IWC counts in January, the majority of the surveyed species (70%) have increased in winter during the last ten years and only 7% of the species have decreased significantly.
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| 6. |
- Alerstam, Thomas, et al.
(författare)
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Migration Along Orthodromic Sun Compass Routes by Arctic Birds
- 2001
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 291:5502, s. 300-303
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Tidskriftsartikel (refereegranskat)abstract
- Flight directions of birds migrating at high geographic and magnetic latitudes can be used to test bird orientation by celestial or geomagnetic compass systems under polar conditions. Migration patterns of arctic shorebirds, revealed by tracking radar studies during an icebreaker expedition along the Northwest Passage in 1999, support predicted sun compass trajectories but cannot be reconciled with orientation along either geographic or magnetic loxodromes (rhumb lines). Sun compass routes are similar to orthodromes (great circle routes) at high latitudes, showing changing geographic courses as the birds traverse longitudes and their internal clock gets out of phase with local time. These routes bring the shorebirds from high arctic Canada to the east coast of North America, from which they make transoceanic flights to South America. The observations are also consistent with a migration link between Siberia and the Beaufort Sea region by way of sun compass routes across the Arctic Ocean.
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| 7. |
- Clausen, P, et al.
(författare)
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Energy limitations for spring migration and breeding: the case of brent geese Branta bernicla tracked by satellite telemetry to Svalbard and Greenland
- 2003
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 103:2, s. 426-445
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Konferensbidrag (refereegranskat)abstract
- Brent geese were tracked by satellite telemetry from spring staging areas in Denmark to Arctic breeding areas in Svalbard and Greenland in 1997 and 2001. From estimated departure masses and carcass analysis we used flight mechnical theory to estimate maximum flight ranges of both sexes, and remaining stores of fat and protein upon arrival in females. Model predictions suggested that all birds but one exceptionally thin male could easily reach Svalbard, but that approximately one third of the males and half of the females would have problems with flying to Greenland. Nevertheless, some birds even flew longer than the models predicted. In addition, females predicted to be capable of making the flight to Greenland, were predicted to arrive almost lean of fat. This contradicts our expectation that these birds are capital breeders - that they depend on endogenous stores of fat and protein when initiating and incubating their eggs. We discuss how the Greenland breeding sub-population during 1985-1998 has been able to grow at the same rate as the sub-population breeding in Svalbard, despite the added flight distance of 700-1000 km, and despite the birds predicted shortage of fat stores on arrival. We suggest four hypotheses that alone or in combination could explain the discrepancy between model predictions and observations. These are that most birds: (1) refuel on stop-overs in Spitsbergen en route to Greenland; (2) pick favourable tail-winds enabling them to reduce flight costs; (3) fly in formation and thereby save energy; and/or (4) undergo gut atrophy immediately prior to departure, and use the nutrients mobilised by catabolism of the digestive system to build larger pectoral muscles. The latter option would both reduce their airframe fraction, and increase their fat and flight-muscle fractions, enabling them to fly longer. We conclude that the latter option seems less likely to operate in brent geese.
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| 8. |
- Green, Martin, et al.
(författare)
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Dark-bellied Brent Geese Branta bernicla bernicla, as recorded by satellite telemetry, do not minimize flight distance during spring migration
- 2002
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Ingår i: Ibis. - : Wiley. - 0019-1019. ; 144:1, s. 106-121
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Tidskriftsartikel (refereegranskat)abstract
- Nine Dark-bellied Brent Geese Branta bernicla bernicla were equipped with satellite transmitters during spring staging in the Dutch Wadden Sea in 1998 and 1999. The transmitters (in all cases less than 3% of body mass) were attached to the back by a flexible elastic harness. One juvenile female was tracked to the Yamal peninsula in 1998. Eight adult males were selected from a single catch of 75 to span the range of body mass observed on the date of capture (11 May 1999) and all but the lightest individual completed the first lap of the migratory flight to the White Sea, Russia, according to the time schedule normal for this species. Six birds were successfully tracked to Taymyr for a total distance averaging 5004 km (range 4577-5164) but judging from later movements none bred (although 1999 was breeding year). Although the routes chosen during spring migration were closely similar; none of the tagged birds migrated together. On average the geese used 16 flights to reach their summer destinations on Taymyr. The longest uninterrupted flights during the first half of the journey (Wadden Sea to Kanin) covered 1056 km (mean of seven adult males, range 768-1331), while the corresponding value for the second half of the migration (Kanin-Taymyr) was only 555 km (mean of six adult males). Only 7% of total time during spring migration was spent in active flight, as contrasted to c. 80% at long-term stopovers. Overall average travelling speed was 118 km/day (range 97-148). Including fattening prior to departure the rate of travel falls to 62 km/day (range 49-70), in keeping with theoretical predictions. Routes followed deviated from the great circle route, adding at least 700 km (16%) to the journey from Wadden Sea to Taymyr, and we conclude that the coastal route is chosen to facilitate feeding, drinking and resting en route instead of minimizing total flight distance.
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| 9. |
- Green, Martin, et al.
(författare)
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Do Arctic waders use adaptive wind drift?
- 2004
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Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 35:4, s. 305-315
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Tidskriftsartikel (refereegranskat)abstract
- We analysed five data sets of night directions of migrating arctic waders ill relation to,winds, recorded by tracking radar and optical range finder, in order to find out if these birds compensate for wind drift, or allow themselves to be drifted by winds. Our purpose was to investigate whether arctic waders use adaptive wind drift strategies or not. The data sets were collected in Siberia (two sets) and Canada during post-breeding (autumn) migration, and in Mauritania and South Sweden during pre-breeding (spring) migration. Both significant drift and compensation effects were found in three of the data sets, Canada, Mauritania and South Sweden. Almost no compensation was found in birds departing in easterly directions from the Siberian tundra (complete drift), while no drift effect was found in birds departing in westerly directions (complete compensation). There were indications that at least some populations of waders may use an adaptive drift strategy consisting of drift at high altitude and/or in high wind speed combined with compensation at low altitude and/or in lower wind speeds, but support for this idea was rather weak and not consistent. Our results were instead more in accordance with the adaptive drift theory that predicts initial drift during the migratory journey, followed by compensation during later stages as the birds are approaching their destinations. Such a strategy implies that arctic waders, at least adult birds, have the capacity of true navigation. A comparison with earlier studies of migrating arctic waders from different parts of the world show that all results so far may be interpreted in accordance with this general adaptive drift strategy An element of non-adaptive drift can, however, not be completely ruled out.
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| 10. |
- Green, Martin, et al.
(författare)
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Flight speeds and climb rates of Brent Geese: mass-dependent differences between spring and autumn migration
- 2000
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Ingår i: Journal of Avian Biology. - 0908-8857. ; 31:2, s. 215-225
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Tidskriftsartikel (refereegranskat)abstract
- Aerodynamic theories of bird flight predict that horizontal flight speed will increase with increasing load whereas vertical Eight speed will decrease. Horizontal flight speed for birds minimizing overall time on migration is predicted to be higher than flight speed for birds minimizing energy expenditure. In this study we compare flight speeds of Brent Geese Branta b. bernicla recorded by tracking radar and optical range finder during spring and autumn migration in southernmost Sweden, testing the above-mentioned predictions. Geese passing Sweden in spring are substantially heavier than in autumn and there might also be a stronger element of time-selection in spring than in autumn. Recorded airspeeds were significantly higher in spring (mean 19.0 m s(-1)) than in autumn (mean 17.3 m s(-1)), the average difference bring slightly larger than predicted due to the mass difference alone. The effects on airspeed of wind, vertical speed, flock size and altitude were also analysed, but none of these factors could explain the seasonal difference in airspeed. Hence, the results support the hypothesis of mass-dependent flight speed adjustment. The difference between the two seasons was not large enough to corroborate the hypothesis of a stronger element of time-selection in spring, but this hypothesis cannot be rejected. Vertical flight speeds were lower in spring than in autumn, supporting a negative effect of load on birds' Right power margin.
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