H. Källander, L. Hansson, C. Brönmark, Alice Nicolle
This paper reports the within-year and between-year variations in the number of waterbirds at Lake Krankesjön, southern Sweden based on counts carried out during 1985 to 2007. The background to these counts was a dramatic decrease in the number of Great Crested Grebe Podiceps cristatus, Mute Swan Cygnus olor and Common Coot Fulica atra from 1974 to 1976, concurrent with a deterioration of water transparency and a nearly total disappearance of submerged vegetation. In 1985, when the regular counts of waterbirds started, the lake had just begun to recover. Numbers of moulting and staging waterbirds increased rapidly as the conditions improved. Numbers of grebes, swans and coots over the two decades correlated with limnological variables, and it is concluded that their numbers depend on the amount of submerged vegetation, in turn determined by water transparency.
{"title":"Waterbird dynamics at the shallow Lake Krankesjön, southern Sweden: a long-term study","authors":"H. Källander, L. Hansson, C. Brönmark, Alice Nicolle","doi":"10.34080/os.v19.22653","DOIUrl":"https://doi.org/10.34080/os.v19.22653","url":null,"abstract":"This paper reports the within-year and between-year variations in the number of waterbirds at Lake Krankesjön, southern Sweden based on counts carried out during 1985 to 2007. The background to these counts was a dramatic decrease in the number of Great Crested Grebe Podiceps cristatus, Mute Swan Cygnus olor and Common Coot Fulica atra from 1974 to 1976, concurrent with a deterioration of water transparency and a nearly total disappearance of submerged vegetation. In 1985, when the regular counts of waterbirds started, the lake had just begun to recover. Numbers of moulting and staging waterbirds increased rapidly as the conditions improved. Numbers of grebes, swans and coots over the two decades correlated with limnological variables, and it is concluded that their numbers depend on the amount of submerged vegetation, in turn determined by water transparency.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761294","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 breeding behaviour of a Treecreeper population that bred in nest pockets and in which all females were colour-ringed was followed over ten seasons. On average, 50% of the first breeding attempts in spring failed. Between half and two thirds of the successful females were double-brooded. The remaining females were single- brooded. These two breeding categories were identical in terms of initial clutch size and egg volume. The double-brooded females invested less in their second than their first clutch. Most of the females that failed laid replacement clutches of similar size as in the first attempt but with larger eggs. A replacement brood where young successfully fledged was never followed by a second breeding attempt. The average distance between the first and the repeat nest was the same for double-brooded and replacement-breeding females. The egg volumes of the first and the repeat clutches were strongly correlated. The double-brooded pairs were the most common breeding category and reared 50% of the population’s total output of fledged broods, while the single-brooded and replacement breeding pairs each fledged ca. 25%. The adaptive values of the three breeding categories are compared.
{"title":"First, second and replacement broods in the breeding biology of a Treecreeper Certhia familiaris population","authors":"A. Enemar","doi":"10.34080/os.v19.23118","DOIUrl":"https://doi.org/10.34080/os.v19.23118","url":null,"abstract":"The breeding behaviour of a Treecreeper population that bred in nest pockets and in which all females were colour-ringed was followed over ten seasons. On average, 50% of the first breeding attempts in spring failed. Between half and two thirds of the successful females were double-brooded. The remaining females were single- brooded. These two breeding categories were identical in terms of initial clutch size and egg volume. The double-brooded females invested less in their second than their first clutch. Most of the females that failed laid replacement clutches of similar size as in the first attempt but with larger eggs. A replacement brood where young successfully fledged was never followed by a second breeding attempt. The average distance between the first and the repeat nest was the same for double-brooded and replacement-breeding females. The egg volumes of the first and the repeat clutches were strongly correlated. The double-brooded pairs were the most common breeding category and reared 50% of the population’s total output of fledged broods, while the single-brooded and replacement breeding pairs each fledged ca. 25%. The adaptive values of the three breeding categories are compared.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761321","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}
Małgorzata Krupa, M. Ściborski, R. Krupa, Rafał Popis, Justyna Wołoszyn
The research was conducted in 2002, in Sajna River valley (NE Poland). It was aimed at foraging ecology of two wader species not specialised in terms of feeding techniques. We found that while foraging on a stopover site during spring migration Ruffs used different ecological niche than Wood Sandpipers. Ruffs foraged significantly more often in medium and deep water and made also more medium and deep probes, what indicates preference in random probing. High intensity and proportionally low efficiency of foraging may confirm it. Contrary, Wood Sandpiper foraged less intensively but much more effectively; this, together with frequent changes of feeding places in terms of water level indicate that Wood Sandpiper to greater extent uses visual detection of prey than Ruff.
{"title":"Differences in foraging ecology of Wood Sandpiper Tringa glareola and Ruff Philomachus pugnax during spring migration in Sajna River valley (nor thern Poland)","authors":"Małgorzata Krupa, M. Ściborski, R. Krupa, Rafał Popis, Justyna Wołoszyn","doi":"10.34080/os.v19.22655","DOIUrl":"https://doi.org/10.34080/os.v19.22655","url":null,"abstract":"The research was conducted in 2002, in Sajna River valley (NE Poland). It was aimed at foraging ecology of two wader species not specialised in terms of feeding techniques. We found that while foraging on a stopover site during spring migration Ruffs used different ecological niche than Wood Sandpipers. Ruffs foraged significantly more often in medium and deep water and made also more medium and deep probes, what indicates preference in random probing. High intensity and proportionally low efficiency of foraging may confirm it. Contrary, Wood Sandpiper foraged less intensively but much more effectively; this, together with frequent changes of feeding places in terms of water level indicate that Wood Sandpiper to greater extent uses visual detection of prey than Ruff.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761350","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}
Territorial behaviour of the Willow Warbler Phylloscopus trochilus was studied in an urbanised habitat in Lesotho, southern Africa, in three consecutive wintering seasons (November–March 1999–2002). Contrary to expectation, the Willow Warblers were holding territories. As many as 34% of all territories were held permanently throughout the wintering season, and 33% were located at the same site for the three consecutive years. The intensity of territoriality (singing) tended to increase as spring migration was approaching (February–March). This was assumed to be a response to an increasing need to defend food resources required for fat deposition before departure. The birds showed a strong preference for feeding in Salix babylonica and Acacia dealbata.
{"title":"Territoriality in the Willow Warbler Phylloscopus trochilus in its winter quarter in Lesotho","authors":"G. Kopij","doi":"10.34080/os.v19.22658","DOIUrl":"https://doi.org/10.34080/os.v19.22658","url":null,"abstract":"Territorial behaviour of the Willow Warbler Phylloscopus trochilus was studied in an urbanised habitat in Lesotho, southern Africa, in three consecutive wintering seasons (November–March 1999–2002). Contrary to expectation, the Willow Warblers were holding territories. As many as 34% of all territories were held permanently throughout the wintering season, and 33% were located at the same site for the three consecutive years. The intensity of territoriality (singing) tended to increase as spring migration was approaching (February–March). This was assumed to be a response to an increasing need to defend food resources required for fat deposition before departure. The birds showed a strong preference for feeding in Salix babylonica and Acacia dealbata.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761463","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}
Several farmland bird species are declining in Sweden. We investigated if the population decreases are linked to smaller broods or a higher rate of unhatched eggs. The number of broods ringed and the average number of nestlings in these broods from 1962 to 2001 were analysed for twelve species: Skylark Alauda arvensis, Swallow Hirundo rustica, House Martin Delichon urbica, Meadow Pipit Anthus pratensis, White Wagtail Motacilla alba, Wheatear Oenanthe oenanthe, Whitethroat Sylvia communis, Starling Sturnus vulgaris, House Sparrow Passer domesticus, Tree Sparrow Passer montanus, Linnet Carduelis cannabina and Yellowhammer Emberiza citrinella. Only two of the investigated species, the Tree Sparrow and the Yellowhammer, showed a statistically significant decline in average brood size over time. We conclude that changes in brood size alone cannot explain the decline in several farmland bird species. The House Sparrow showed an increase in the number of dead nestlings and data for House Sparrow, Tree Sparrow and Whitethroat indicated that a higher rate of unhatched eggs might be a problem.
{"title":"Brood size of twelve farmland bird species in Sweden during 1962—2001","authors":"H. Ryttman, K. S. S. Hall‐Karlsson","doi":"10.34080/os.v19.22665","DOIUrl":"https://doi.org/10.34080/os.v19.22665","url":null,"abstract":"Several farmland bird species are declining in Sweden. We investigated if the population decreases are linked to smaller broods or a higher rate of unhatched eggs. The number of broods ringed and the average number of nestlings in these broods from 1962 to 2001 were analysed for twelve species: Skylark Alauda arvensis, Swallow Hirundo rustica, House Martin Delichon urbica, Meadow Pipit Anthus pratensis, White Wagtail Motacilla alba, Wheatear Oenanthe oenanthe, Whitethroat Sylvia communis, Starling Sturnus vulgaris, House Sparrow Passer domesticus, Tree Sparrow Passer montanus, Linnet Carduelis cannabina and Yellowhammer Emberiza citrinella. Only two of the investigated species, the Tree Sparrow and the Yellowhammer, showed a statistically significant decline in average brood size over time. We conclude that changes in brood size alone cannot explain the decline in several farmland bird species. The House Sparrow showed an increase in the number of dead nestlings and data for House Sparrow, Tree Sparrow and Whitethroat indicated that a higher rate of unhatched eggs might be a problem.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"34 4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761726","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}
We assessed the quality of organic set-asides as habitat for breeding Skylarks. We evaluated (i) density in relation to vegetation structure and landscape composition, (ii) reproductive success on set-asides cut at normal time (1 June) and with delayed cutting (15 June), and (iii) nest predation and destruction by using artificial nests. Skylark density was negatively associated with vegetation height and cover, and it was three times higher on fields without forest than with more than 50% forest in the surrounding landscape. Of the artificial nests, 56% were destroyed by cutting that also increased predation on surviving nests. Delayed cutting resulted in higher reproductive success; mean number of fledged broods per territory increased from 0.42 to 0.52. The negative effects of early cutting seemed to be largest on fields with sparse vegetation. Based on fledging dates we suggest that 20 June is a reasonable date for first cutting in south-central Sweden. Reproductive success on organic set-asides could probably be further improved if less dense vegetation (or unsown patches or strips) is combined with a delayed cutting.
{"title":"Breeding Skylarks Alauda arvensis on organic set-asides—effects of time of cutting, vegetation structure and landscape composition","authors":"Åke Berg, Olle Kvarnbäck, Å. Gustafsson","doi":"10.34080/os.v19.22666","DOIUrl":"https://doi.org/10.34080/os.v19.22666","url":null,"abstract":"We assessed the quality of organic set-asides as habitat for breeding Skylarks. We evaluated (i) density in relation to vegetation structure and landscape composition, (ii) reproductive success on set-asides cut at normal time (1 June) and with delayed cutting (15 June), and (iii) nest predation and destruction by using artificial nests. Skylark density was negatively associated with vegetation height and cover, and it was three times higher on fields without forest than with more than 50% forest in the surrounding landscape. Of the artificial nests, 56% were destroyed by cutting that also increased predation on surviving nests. Delayed cutting resulted in higher reproductive success; mean number of fledged broods per territory increased from 0.42 to 0.52. The negative effects of early cutting seemed to be largest on fields with sparse vegetation. Based on fledging dates we suggest that 20 June is a reasonable date for first cutting in south-central Sweden. Reproductive success on organic set-asides could probably be further improved if less dense vegetation (or unsown patches or strips) is combined with a delayed cutting.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761278","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":"The first record of melanism in the Red-backed Shrike Lanius collurio","authors":"M. Ciach","doi":"10.34080/os.v19.22657","DOIUrl":"https://doi.org/10.34080/os.v19.22657","url":null,"abstract":"","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761402","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}
Ornis Svecica, Daniel Bengtsson, T. Fransson, J. E. Røer
A recent increase of wintering Blackcaps in Scandinavia is suspected to derive from migration from central Europe. We used ringing recoveries to determine their origin. Because Blackcaps breeding in Scandinavia have longer wings than more southern Blackcaps, we also analysed wing length data from seven Nordic bird observatories to see whether there was an influx of short-winged, probably continental Blackcaps. The results showed that Scandinavia is now a part of the Blackcap’s regular wintering range. As many as 17% of Blackcaps ringed in Sweden and found again during the same autumn were recovered north of an E–W axis. This is an outstandingly high figure compared to 0–7% in some other species. A strong significant difference in dates of ringing was discovered between “long-winged” (>73 mm) and “short-winged” (<74 mm) Blackcaps. An influx of short-winged Blackcaps started in late September and this was more pronounced in Norway than in Sweden and Finland. It is probably these birds, not Scandinavian breeders forestalling migration, that are observed at bird tables during the winter.
{"title":"Occurrence of Continental Blackcaps Sylvia atricapilla in northern Europe","authors":"Ornis Svecica, Daniel Bengtsson, T. Fransson, J. E. Røer","doi":"10.34080/os.v19.22660","DOIUrl":"https://doi.org/10.34080/os.v19.22660","url":null,"abstract":"A recent increase of wintering Blackcaps in Scandinavia is suspected to derive from migration from central Europe. We used ringing recoveries to determine their origin. Because Blackcaps breeding in Scandinavia have longer wings than more southern Blackcaps, we also analysed wing length data from seven Nordic bird observatories to see whether there was an influx of short-winged, probably continental Blackcaps. The results showed that Scandinavia is now a part of the Blackcap’s regular wintering range. As many as 17% of Blackcaps ringed in Sweden and found again during the same autumn were recovered north of an E–W axis. This is an outstandingly high figure compared to 0–7% in some other species. A strong significant difference in dates of ringing was discovered between “long-winged” (>73 mm) and “short-winged” (<74 mm) Blackcaps. An influx of short-winged Blackcaps started in late September and this was more pronounced in Norway than in Sweden and Finland. It is probably these birds, not Scandinavian breeders forestalling migration, that are observed at bird tables during the winter.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761540","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}
En melanistisk törnskata påträffades nära Lipnica Wielka (Karpaterna, södra Polen) den 16 maj 2007. Manteln samt undersidan och stjärten var mörkbruna och vingarna med sina täckare svartbruna. Huvud och hals var något ljusare bruna och runt ögat fanns en mörk mask. Övergumpen och stjärtfjädrarnas baser var något ljusbrunare. De yttre stjärtpennorna var tydligt ljusare än de inre och kontrasterade klart mot de senare. Näbben var svart och benen normalt mörkgrå. Fågelns beteende var helt normalt och den uppträdde i sällskap med två normalt färgade törnskator. Detta är det första fyndet av melanism hos någon törnskata.
{"title":"Long handling time of a big prey—Great Reed Warbler Acrocephalus arundinaceus foraging on frog","authors":"D. Jakubas, K. Wojczulanis-Jakubas","doi":"10.34080/os.v19.22661","DOIUrl":"https://doi.org/10.34080/os.v19.22661","url":null,"abstract":"En melanistisk törnskata påträffades nära Lipnica Wielka (Karpaterna, södra Polen) den 16 maj 2007. Manteln samt undersidan och stjärten var mörkbruna och vingarna med sina täckare svartbruna. Huvud och hals var något ljusare bruna och runt ögat fanns en mörk mask. Övergumpen och stjärtfjädrarnas baser var något ljusbrunare. De yttre stjärtpennorna var tydligt ljusare än de inre och kontrasterade klart mot de senare. Näbben var svart och benen normalt mörkgrå. Fågelns beteende var helt normalt och den uppträdde i sällskap med två normalt färgade törnskator. Detta är det första fyndet av melanism hos någon törnskata.","PeriodicalId":52418,"journal":{"name":"Ornis Svecica","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69761609","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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