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- Andersson, Åke, et al.
(författare)
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Migration Patterns of Nordic Greylag Geese Anser anser.
- 2001
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Ingår i: Ornis Svecica. - 1102-6812. ; 11, s. 19-58
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Tidskriftsartikel (refereegranskat)abstract
- Migration patterns of Nordic Greylag Geese Anser anserwere studied by means of neck-collaring. A total of 4173birds (738 breeders, 1999 goslings and 1436 moulters;most moulters subsequently identified as belonging to aspecified breeding population) was marked throughoutNorway, Sweden, Denmark and Finland during 1984–1994. This report is based on observations made up to 30June 1995. In general, Norwegian Greylag Geese left theirbreeding areas rapidly for staging areas in Denmark and/or the Netherlands during the period late August – earlySeptember, but the most northerly breeding populationsmigrated south much later and not so rapidly. After a longrefuelling period most Norwegian Greylags left theNetherlands for wintering areas in Spain during November.The Guadalquivir Marismas in the south-western part ofthe country was the main wintering area, but sites in theDuero Basin in the north-central part gained importancethroughout the study period. Normally, the geese left Spainin February, for a long stop-over in the Netherlands.Breeders returned to Vega in Norway in April, but to Tromsand Finnmark not until May. Most Greylags from Scaniaand Denmark, all belonging to the West Baltic population,remained in the breeding area until October, merging intolarger and larger flocks, together with returning moultersand birds from more northern breeding grounds. Themajority made only a short stop-over in the Netherlandsen-route to their main winter quarter, the GuadalquivirMarismas, Spain. An increasing proportion wintered in theDutch Delta. In general, West Baltic Greylags left theirwinter quarters during the first two weeks of February andmigrated rapidly to the breeding grounds. Largely,Norwegian and West Baltic Greylags used different stagingareas in the Netherlands and non-overlapping feedingareas in Spain. Outside the Atlantic flyway there is a fewre-sightings from England of Norwegian and Swedishbirds as well as one re-sighting each from Scotland andHungary of a Swedish Greylag. Finnish reylags werefound along both the Atlantic flyway, down to theGuadalquivir Marismas, and the Continental flyway, downto Tunisia and Algeria. Winter quarters of the two studiednaturalised populations were situated apart from the mainones; Greylags from the Oslo area wintered in theNetherlands and the majority from Södermanland at Lacdu Der, east of Paris.
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| 3. |
- 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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| 4. |
- Barshep, Yahkat, et al.
(författare)
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Non-breeding ecology of the Whinchat Saxicola rubetra in Nigeria
- 2012
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Ingår i: Ornis Svecica. - 1102-6812 .- 2003-2633. ; 22, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- This study on the non-breeding ecology of the Whinchat Saxicola rubetra was conducted in central Nigeria from February through April. The core site was at Gwafan (N09°53', E08°57'), an open scrubland located 10 km east of the city of Jos. The density of Whinchats at Gwafan was 0.58 individuals/ha, almost three times the overall density around Jos. Time budget observations of colour banded Whinchats, including six birds fitted with radio-transmitters, showed that they spent 80% of their time perching, 11% foraging, 7% preening, and 2% flying. The main method of catching insects was a swoop to the ground. There was no change in perching, preening or flying time but the time some Whinchats spent foraging increased towards the end of the study period. GPS positions of individuals showed that all birds held clearly demarcated territories and defended them against neighbours. Aggressive interactions were also recorded between Whinchats and other bird species. Three birds colour-ringed in 2006 returned to the study site in 2007 and one occupied almost the same territory, indicating site fidelity.
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| 5. |
- Bengtsson, Daniel, et al.
(författare)
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Age and sex determination of mallards Anas platyrhynchos in autumn
- 2016
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Ingår i: Ornis Svecica. - 1102-6812 .- 2003-2633. ; 26, s. 61-81
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Tidskriftsartikel (refereegranskat)abstract
- The mallard is a well-known and important species in migration ecology, game management,and epidemiology. Males and females are generally easily told apart, whereas ageing isproblematic, due to individual timing of the moult cycle and lack of easily defined agecriteria. From examination and photographic documentation of mallards caught within a longtermringing program at Ottenby Bird Observatory (56°12′N, 16°24′E), we describe ninecharacters of plumage and bare parts to be used for ageing mallards in autumn. The reliabilityof these characters was tested by letting experienced bird ringers determine putative age ofbirds from photos. Age determination from any single character proved to be uncertain, as therate of correctly assigned mallard photos of each character was in the range of 51-85% formales and 48-89% for females. For both sexes, the lowest figure represented post-humeralsand the highest represented tertials. Rectrices, tertial coverts, and greater coverts also hadreasonably high scores (71-85%). With all characters at hand, 91% of the males and 95% ofthe females were correctly identified to age. As young mallards, with the progress of prebreedingmoult (completed from October onwards), acquire tail and tertials identical to adults,untypical individuals are better not assigned to an age category.
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| 10. |
- Berg, Åke
(författare)
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Density and reproductive success of Skylarks Alauda arvensis on organic farms - an experiment with unsown Sylark plots
- 2011
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Ingår i: Ornis Svecica. - 1102-6812. ; 21, s. 3-10
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Tidskriftsartikel (refereegranskat)abstract
- Skylark plots (unsown plots; 10–25 m2 per ha) in autumn cereal fields have had positive effects on Skylark density and reproductive success on conventional farms in Britain. We tested if the same effect could be found in organic farms in Sweden by comparing paired fields with and without unsown plots in similar settings. We found that the plots had no effect. Skylark density was only associated (negatively) with field size and not with occurrence of Skylark plots, vegetation structure, yield or weed harrowing. Number of clutches per territory was affected by yield (negative) and vegetation cover (positive) but not by Skylark plots. Number of fledglings per clutch showed negative association with yield and visibility through the sward. The amount of weed was larger near Skylark plots from the preceding year than in other parts of the field. The yield (and probably vegetation density) was lower on these fields than in conventional autumn sown fields, but still negative effects of the crop (yield levels) were found.
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