During an invasion in 2005, 164 Pygmy Owls were trapped and ringed at Hammarö Bird Observatory on the north coast of lake Vänern between 28 August and 31 October using play-back of territorial male calls. The most intensive migration was recorded in the third decade of September. Eighty percent of the owls were females. There was no difference in the timing of migration of males and females. More than eighty percent were yearlings, and they were migrating earlier than adults. Most Pygmy Owls were trapped at dawn, but some also in the evening, at night and during the day. Two recoveries were received, an immature bird controlled 123 km to the west in the same autumn and another immature individual from Nordre Osen, Hedmark, Norway in March 2008 (247 km to NNW). Twelve re-traps were made at the ringing site, each bird only once and on average one week after ringing with the longest staying bird controlled 22 days after ringing. The paper also shows photographs demonstrating the different wing patterns of yearling and adults.
{"title":"Sex and age composition during autumn migration of Pygmy Owl Glaucidium passerinum in Central Sweden in 2005","authors":"M. Polakowski, M. Broniszewska, M. Skierczyǹski","doi":"10.34080/os.v18.22668","DOIUrl":"https://doi.org/10.34080/os.v18.22668","url":null,"abstract":"During an invasion in 2005, 164 Pygmy Owls were trapped and ringed at Hammarö Bird Observatory on the north coast of lake Vänern between 28 August and 31 October using play-back of territorial male calls. The most intensive migration was recorded in the third decade of September. Eighty percent of the owls were females. There was no difference in the timing of migration of males and females. More than eighty percent were yearlings, and they were migrating earlier than adults. Most Pygmy Owls were trapped at dawn, but some also in the evening, at night and during the day. Two recoveries were received, an immature bird controlled 123 km to the west in the same autumn and another immature individual from Nordre Osen, Hedmark, Norway in March 2008 (247 km to NNW). Twelve re-traps were made at the ringing site, each bird only once and on average one week after ringing with the longest staying bird controlled 22 days after ringing. The paper also shows photographs demonstrating the different wing patterns of yearling and adults.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69760911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ejderns Somateria mollisima boplatstrohet i en koloni på Utklippan i Östersjön","authors":"R. Larsson","doi":"10.34080/os.v18.22676","DOIUrl":"https://doi.org/10.34080/os.v18.22676","url":null,"abstract":"","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A Fieldfare population, on average c. 160 pairs, was studied in subalpine birch forest in southern Lapland (c. 66°N; 500–600 m.a.s.l.) in 1983–2002. Onset of egg-laying showed no temporal trend, consistent with absence of spring temperature trend. Eggs were laid with an interval of c. 21 hours and 45 minutes, not 24 hours as normal in passerines. This reduces the exposure time to depredation during egg-laying with 9%. Egg hatchability was 96%. Egg parasitism never occurred. Depredation of nests was 46%, but very variable. Replacement and second clutches did not occur. Although an average of 4.45 young fledged from successful nests (≥1 fledgling), only 2.11 fledglings were produced per pair and year. The population varied without trend over the study period. Adult survival, estimated by the proportion of adults at the start of breeding, was 58%. This infers that first year survival must be at least c. 40%. Since this is a likely value, it seems that the Fieldfare population of the subalpine birch forest is selfsustained and not dependent upon immigration.
{"title":"Breeding performance of the Fieldfare Turdus pilaris in the subalpine birch zone in southern Lapland: a 20 year study","authors":"Ola Arheimer, S. Svensson","doi":"10.34080/os.v18.22679","DOIUrl":"https://doi.org/10.34080/os.v18.22679","url":null,"abstract":"A Fieldfare population, on average c. 160 pairs, was studied in subalpine birch forest in southern Lapland (c. 66°N; 500–600 m.a.s.l.) in 1983–2002. Onset of egg-laying showed no temporal trend, consistent with absence of spring temperature trend. Eggs were laid with an interval of c. 21 hours and 45 minutes, not 24 hours as normal in passerines. This reduces the exposure time to depredation during egg-laying with 9%. Egg hatchability was 96%. Egg parasitism never occurred. Depredation of nests was 46%, but very variable. Replacement and second clutches did not occur. Although an average of 4.45 young fledged from successful nests (≥1 fledgling), only 2.11 fledglings were produced per pair and year. The population varied without trend over the study period. Adult survival, estimated by the proportion of adults at the start of breeding, was 58%. This infers that first year survival must be at least c. 40%. Since this is a likely value, it seems that the Fieldfare population of the subalpine birch forest is selfsustained and not dependent upon immigration.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Taiga Bean Goose Anser fabalis fabalis is one of few goose species under current decline. The species uses three flyways: the Scandinavian population migrates west of the Baltic Sea and the Bothnian Bay, the Finnish and western Russian populations take a central flyway, and the central Russian population migrates east of the Baltic Sea. On 17–21 March 2007, the number of birds using the western and the central flyways were counted at all staging sites in southern Sweden. During the count, practically the whole western and central flyway populations were concentrated in southern Sweden. We estimated the number of birds at 56,000. Recent estimates suggest that 5,000–6,000 of these birds breed in Scandinavia and use the western flyway. This means that approximately 50,000 birds used the central flyway. Assuming that a maximum of 30,000 birds wintered in Germany and used the eastern flyway, the global population of the Taiga Bean Goose amounted to a maximum of 85,000 birds. This is about 15,000 birds less than an estimate from 1999.
{"title":"Spring staging of Taiga Bean Goose Anser f. fabalis in southern Sweden 2007—estimate of the size of populations using the western and central flyways","authors":"U. Skyllberg, Martin Tjernberg","doi":"10.34080/os.v18.22677","DOIUrl":"https://doi.org/10.34080/os.v18.22677","url":null,"abstract":"The Taiga Bean Goose Anser fabalis fabalis is one of few goose species under current decline. The species uses three flyways: the Scandinavian population migrates west of the Baltic Sea and the Bothnian Bay, the Finnish and western Russian populations take a central flyway, and the central Russian population migrates east of the Baltic Sea. On 17–21 March 2007, the number of birds using the western and the central flyways were counted at all staging sites in southern Sweden. During the count, practically the whole western and central flyway populations were concentrated in southern Sweden. We estimated the number of birds at 56,000. Recent estimates suggest that 5,000–6,000 of these birds breed in Scandinavia and use the western flyway. This means that approximately 50,000 birds used the central flyway. Assuming that a maximum of 30,000 birds wintered in Germany and used the eastern flyway, the global population of the Taiga Bean Goose amounted to a maximum of 85,000 birds. This is about 15,000 birds less than an estimate from 1999.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mute Swan time-activity budget was studied on a municipal beach in two consecutive winter seasons, 2005 and 2006. The major difference between years in activity pattern was that adult swans decreased minimum feeding time, rested less and moved more in 2006. This year air temperatures were lower at the same time as humans provided less bread due to avian influenza fear. Despite higher energy expenditure in 2006, Mute Swans did not increase the total feeding time, probably because they still met metabolic demands. In 2006 the amount of aggressive attacks (mostly by adults on juveniles) increased.
{"title":"Behaviour of Mute Swans Cygnus olor wintering at a municipal beach in Gdynia, Poland","authors":"W. Meissner, Katarzyna Ciopcińska","doi":"10.34080/os.v17.22685","DOIUrl":"https://doi.org/10.34080/os.v17.22685","url":null,"abstract":"Mute Swan time-activity budget was studied on a municipal beach in two consecutive winter seasons, 2005 and 2006. The major difference between years in activity pattern was that adult swans decreased minimum feeding time, rested less and moved more in 2006. This year air temperatures were lower at the same time as humans provided less bread due to avian influenza fear. Despite higher energy expenditure in 2006, Mute Swans did not increase the total feeding time, probably because they still met metabolic demands. In 2006 the amount of aggressive attacks (mostly by adults on juveniles) increased.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69760611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In 1976—1995, 74,650 Grey Plovers Pluvialis squatarola were recorded on spring passage, 87% in the southern third of Sweden, and 59% while in migratory flight. Few were observed before May. The passage peaked 24 May—2 June (83%). About one fourth of all birds were observed on a few occasions, when grounded by inclement weather, showing that only a tiny fraction stops over regularly. In northern Sweden, passage peaked earlier (18 May) than in the south (29 May), and these early birds were presumably destined for breeding or staging in the White Sea region. The peak dates in southern Sweden correlate well with arrival time in Siberia, indicating a non-stop flight to these breeding areas. Flocks counted up to several hundred birds in the south but at most 34 birds in the north. Migration patterns along the East Atlantic Flyway were similar with those of the East African/ West Asian and Mediterranian/Black Sea flyways. The spring passage of the Grey Plover conforms to the migration system of other tundra waders passing up through the western Palaearctic.
{"title":"The spring migration of Grey Plover Pluvialis squatarola in Sweden","authors":"S. Blomqvist, Martin Green, Å. Lindström","doi":"10.34080/os.v17.22680","DOIUrl":"https://doi.org/10.34080/os.v17.22680","url":null,"abstract":"In 1976—1995, 74,650 Grey Plovers Pluvialis squatarola were recorded on spring passage, 87% in the southern third of Sweden, and 59% while in migratory flight. Few were observed before May. The passage peaked 24 May—2 June (83%). About one fourth of all birds were observed on a few occasions, when grounded by inclement weather, showing that only a tiny fraction stops over regularly. In northern Sweden, passage peaked earlier (18 May) than in the south (29 May), and these early birds were presumably destined for breeding or staging in the White Sea region. The peak dates in southern Sweden correlate well with arrival time in Siberia, indicating a non-stop flight to these breeding areas. Flocks counted up to several hundred birds in the south but at most 34 birds in the north. Migration patterns along the East Atlantic Flyway were similar with those of the East African/ West Asian and Mediterranian/Black Sea flyways. The spring passage of the Grey Plover conforms to the migration system of other tundra waders passing up through the western Palaearctic.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69760237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This report provides basic data about hybrid geese and mixed pairs in Sweden; combinations of species, numbers, trends and origins, which can serve as a framework for future studies. Data published in national, regional and local magazines and reports as well as unpublished observations through August 2007 have been analysed. Sightings in this report were based on the observers’ suggestion of parent species. No less than 17 species were involved in the hybrid geese sighted in Sweden. Some of the combinations of species involved the red-listed species Lesser White-fronted Goose, the nominate race of Taiga Bean Goose and Red-breasted Goose. The first combinations of species appeared in Sweden already 1918–1930s, but since the last half a century, the number of hybrid geese in Sweden shows a positive trend. Several explanations to this increasing trend is proposed but not further analysed. Among all the several theories proposed for hybridisation in geese, field data from Swedish goose haunts support at least two; the ”Best-Option-Hypothesis” and ”Interspecific mate choice following false imprinting”.
{"title":"Occurrence of hybrid geese in Sweden—a conservation problem?","authors":"Henrik Lerner, Hakon Kampe-Persson","doi":"10.34080/os.v17.22681","DOIUrl":"https://doi.org/10.34080/os.v17.22681","url":null,"abstract":"This report provides basic data about hybrid geese and mixed pairs in Sweden; combinations of species, numbers, trends and origins, which can serve as a framework for future studies. Data published in national, regional and local magazines and reports as well as unpublished observations through August 2007 have been analysed. Sightings in this report were based on the observers’ suggestion of parent species. No less than 17 species were involved in the hybrid geese sighted in Sweden. Some of the combinations of species involved the red-listed species Lesser White-fronted Goose, the nominate race of Taiga Bean Goose and Red-breasted Goose. The first combinations of species appeared in Sweden already 1918–1930s, but since the last half a century, the number of hybrid geese in Sweden shows a positive trend. Several explanations to this increasing trend is proposed but not further analysed. Among all the several theories proposed for hybridisation in geese, field data from Swedish goose haunts support at least two; the ”Best-Option-Hypothesis” and ”Interspecific mate choice following false imprinting”.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69760310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Häckning i träd – en ny trend bland svenska grågäss?","authors":"Hakon Kampe-Persson","doi":"10.34080/os.v17.22683","DOIUrl":"https://doi.org/10.34080/os.v17.22683","url":null,"abstract":"","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69760510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The sex ratio of the Eurasian Wigeon Anas penelope and its seasonal variation was studied during eleven spring migrations at Angarnsjöängen, Sweden (59° 33'N, 18° 10'E). The main passage of birds occurred in the second half of April, and the migration had almost ceased after 15 May. Eurasian Wigeons recorded after this date were mainly males and probably mostly non-breeders, moult migrants or stragglers. The fraction of males was 0.53 (SD=0.028), and there was no difference between years. Neither was there a correlation between the fraction of males and the flock size. About 95% of the females and 85% of the males were paired during the stopover.
{"title":"Könsfördelningen hos bläsand Anas penelope under vårsträcket vid Angarnsjöängen, Uppland, 1995—2005","authors":"Svante Söderholm","doi":"10.34080/os.v17.22682","DOIUrl":"https://doi.org/10.34080/os.v17.22682","url":null,"abstract":"The sex ratio of the Eurasian Wigeon Anas penelope and its seasonal variation was studied during eleven spring migrations at Angarnsjöängen, Sweden (59° 33'N, 18° 10'E). The main passage of birds occurred in the second half of April, and the migration had almost ceased after 15 May. Eurasian Wigeons recorded after this date were mainly males and probably mostly non-breeders, moult migrants or stragglers. The fraction of males was 0.53 (SD=0.028), and there was no difference between years. Neither was there a correlation between the fraction of males and the flock size. About 95% of the females and 85% of the males were paired during the stopover.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69760442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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