| 1. |
- Hansson, Bengt, et al.
(författare)
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Increase of genetic variation over time in a recently founded population of great reed warblers (Acrocephalus arundinaceus) revealed by microsatellites and DNA fingerprinting
- 2000
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Ingår i: Molecular Ecology. - : Wiley. - 0962-1083 .- 1365-294X. ; 9:10, s. 1529-1538
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Tidskriftsartikel (refereegranskat)abstract
- Genetic similarity within pairs of individuals was examined using both 10 polymorphic microsatellite loci and multi-locus DNA fingerprinting profiles in a semi-isolated population of great reed warblers at Lake Kvismaren, south Central Sweden, in 1987-1993. The population was founded by a few individuals in 1978, followed by a gradual increase in numbers until 1988, since when the population has remained relatively stable with about 60 breeding birds. We have previously found that high genetic similarity between pairmates in the population during the early part of the study period reduced egg hatching success, and hence reproductive success. The measures of pairwise genetic similarity, microsatellite allele sharing and DNA fingerprinting band sharing, were highly correlated with pedigree-based relatedness. Both microsatellite and DNA fingerprinting similarities between pair-mates declined significantly over the study period, and the pattern was most pronounced in the DNA fingerprinting data. Analyses restricted to the microsatellite data showed that the average annual microsatellite similarity between pairwise combinations of individuals, as well as individual homozygosity in males, declined significantly over the study period, and that several immigrants carrying novel alleles entered the population during the study. Hence, the temporal decline in genetic similarity of mates in the population is probably a consequence of increased immigration, facilitated by the recent expansion of the species in the region. These results suggest that the population has now recovered genetically, or is in the process of recovering, from a recent founder event.
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| 2. |
- Holmgren, NMA, et al.
(författare)
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Geographical variation in the timing of breeding and moult in dunlin Calidris alpina on the Palearctic tundra
- 2001
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Ingår i: Polar Biology. - : Springer Science and Business Media LLC. - 1432-2056 .- 0722-4060. ; 24:5, s. 369-377
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Tidskriftsartikel (refereegranskat)abstract
- Studies of how organisms are adapted to regional climatic conditions are valuable when predicting the effects of global climatic changes on biota. Here we report on the geographical variation in timing of breeding and moult of an Arctic breeding wader, the dunlin (Calidris alpina). The Palearctic study sites range latitudinally between 68 and 76 degreesN and longitudinally between 46 and 179 degreesE, and encompass a variety of local climates. The sites were visited in sequence from west to east within 1 year, and therefore the data are not affected by confounding interannual variations. The estimated breeding start ranged from 5 to 25 June across populations. Birds at more southern sites were found to breed earlier than those at more northern breeding sites. Within populations, the breeding start for first clutches spanned a period of 8 days and, when including replacement clutches, 3-4 weeks. No dunlin west of the Taimyr Peninsula were found moulting while incubating at the nest, whereas all dunlin on Taimyr Peninsula and eastwards were in active wing moult while incubating or rearing chicks. The onset of moult in these populations ranged from 23 to 27 June. The consequences of geographical variation of breeding conditions for variation in the annual cycle of this species are discussed.
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| 3. |
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| 4. |
- Lindström, Åke, et al.
(författare)
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A Puzzling Migratory Detour: Are Fueling Conditions In Alaska Driving The Movement Of Juvenile Sharp-Tailed Sandpipers?
- 2011
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Ingår i: The Condor: ornithological applications. - : Oxford University Press (OUP). - 0010-5422. ; 113:1, s. 129-139
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Tidskriftsartikel (refereegranskat)abstract
- Making a detour can be advantageous to a migrating bird if fuel-deposition rates at stopover sites along the detour are considerably higher than at stopover sites along a more direct route. One example of an extensive migratory detour is that of the Sharp-tailed Sandpiper (Calidris acuminata), of which large numbers of juveniles are found during fall migration in western Alaska. These birds take a detour of 1500-3400 km from the most direct route between their natal range in northeastern Siberia and nonbreeding areas in Australia. We studied the autumnal fueling rates and fuel loads of 357 Sharp-tailed Sandpipers captured in western Alaska. In early September the birds increased in mass at a rate of only 0.5% of lean body mass day(-1). Later in September, the rate of mass increase was about 6% of lean body mass day(-1), among the highest values found among similar-sized shorebirds around the world. Some individuals more than doubled their body mass because of fuel deposition, allowing non-stop flight of between 7100 and 9800 km, presumably including a trans-oceanic flight to the southern hemisphere. Our observations indicated that predator attacks were rare in our study area, adding another potential benefit of the detour. We conclude that the most likely reason for the Alaskan detour is that it allows juvenile Sharp-tailed Sand-pipers to put on large fuel stores at exceptionally high rates.
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| 5. |
- Lindström, Åke, et al.
(författare)
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Fuel stores of juvenile waders on autumn migration in high arctic Canada
- 2002
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Ingår i: Ardea. - 0373-2266. ; 90:1, s. 93-101
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about the fuel stores that arctic-breeding waders put on before departure from the breeding grounds. During a ship-based expedition to arctic Canada, we caught waders at seven, mainly coastal sites, within 68degrees-76degreesN and 139degrees-67degreesW, from 28 July to 31 August 1999. More than two hundred waders of twelve species were trapped, mainly White-rumped Calidris fuscicollis, Semipalmated C. pusilla, Baird's C. bairdii and Buff-breasted Sandpipers Tryngites subruficollis. The vast majority of the birds were juveniles. Body masses and visual fat stores were low, close to the lowest values found anywhere during the non-breeding season for the different species. The relatively fattest birds were Buff-breasted Sandpipers, but they were still far from their maximum body mass on spring migration. We conclude that juvenile arctic waders depart from their natal areas with only small fuel stores, which is in concordance with a time-minimising migration strategy.
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| 6. |
- Smith, Henrik, et al.
(författare)
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Adoption or infanticide: Options of replacement males in the European starling
- 1996
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 1432-0762 .- 0340-5443. ; 38:3, s. 191-197
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Tidskriftsartikel (refereegranskat)abstract
- The behaviour of a male bird towards a potential mate and her clutch may depend both on his expected paternity and on the likelihood that she will produce a replacement clutch if he commits infanticide. In this study we evaluate the choices made by replacement male European starlings Sturnus vulgaris. By removing males before and during laying, we induced other males, mainly neighbours, to mate with the reproductively active females. When the original male was removed before laying, a new male adopted the subsequent clutch in 14 out of 15 cases. When ten females were widowed during their laying period, replacement males never adopted their clutches. The paternity of replacement males was a function of when they replaced the former male. When replacement occurred more than 3 days before egglaying, the new male fathered nearly all offspring; when it occurred the day before laying, the new male still fathered more than every second young. When the original male was removed during his mate's laying period, in five out of ten cases a replacement male committed infanticide by throwing out the eggs, but this only occurred in one out of 15 cases when removal took place before laying. The evidence for infanticide actually being committed by the replacement male was circumstantial. Four out of six of the females affected by apparent infanticide produced replacement clutches in which the male presumably had higher paternity than in the original clutch. In all cases, the male adopted the replacement clutch. In five cases when the original male was removed during laying, the neighbours neither adopted the brood nor committed infanticide, although they sometimes were seen courting the widowed female and copulating with her. These cases occurred later during laying than those were males comitted infanticide. The time from infanticide to the laying of the replacement clutch tended to increase as infanticide was committed later in the laying sequence. We conclude that strategies of potential replacement males are influenced by their expected paternity in the current brood and the probability that the female will produce an early replacement clutch.
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| 7. |
- Smith, Henrik, et al.
(författare)
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Sperm competition in the European starling (Sturnus vulgaris): An experimental study of mate switching
- 1996
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Ingår i: Royal Society of London. Proceedings B. Biological Sciences. - : The Royal Society. - 1471-2954. ; 263:1371, s. 797-801
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Tidskriftsartikel (refereegranskat)abstract
- In apparently monogamous or polygynous birds, sperm from several males may compete to fertilize the eggs laid by one female. In this study we evaluate sperm competition in the European starling (Sturnus vulgaris) by means of a mate-switching experiment. Already-mated males were removed between 1-7 d before their mates started egg-laying, resulting in the female remating with a new male. The original males' parentage in the subsequent clutches was evaluated using DNA-fingerprinting. The original males fathered only two out of 46 eggs of those which were not likely to have been fertilized already when the males were removed. The low success of the original males can be attributed to a high within-pair copulation frequency during the assumed fertile period before laying and throughout the laying period, resulting in replacement males fathering most offspring. Thus the success of extra-pair copulations more than 2 d before egg-laying is probably very low. The results are discussed in relation to contrasting results from other mate-switching studies.
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| 8. |
- Wennerberg, Liv
(författare)
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Breeding origin and migration pattern of dunlin (Calidris alpina) revealed by mitochondrial DNA analysis.
- 2001
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Ingår i: Molecular Ecology. - 0962-1083. ; 10:5, s. 1111-1120
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Tidskriftsartikel (refereegranskat)abstract
- The large-scale migration of birds has been studied extensively by recoveries of ringed birds. However, there is very little ringing data from the arctic breeding grounds of waders. Here, the migration pattern of the dunlin, Calidris alpina, is studied with population genetic markers, using haplotype frequencies to estimate the breeding origin of migrating and wintering populations. Polymerase chain reaction (PCR) and restriction analysis of DNA from the mitochondrial control region was used to study the breeding origins of morphologically similar winter populations in the western Palaearctic, and to describe the population structure of the dunlin during winter. Also migrating dunlin from various stopover sites in Europe, Africa and Asia, were analysed with respect to their mitochondrial DNA (mtDNA) haplotypes. The genetic markers clearly show that the dunlin has a parallel migration system, with populations breeding in the western Palaearctic wintering mainly in the western part of the wintering range, and dunlin populations breeding further east wintering further east. The results also show that the distance between breeding and wintering area increases eastwards in this region.
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| 9. |
- Wennerberg, Liv, et al.
(författare)
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Genetic and morphological variation in Dunlin Calidris alpina breeding in the Palearctic tundra
- 1999
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Ingår i: Ibis. - 0019-1019. ; 141:3, s. 391-398
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Tidskriftsartikel (refereegranskat)abstract
- The extensive overlap in morphological characters between populations of Dunlin Calidris alpina imposes problems of determining the origin of migrating and wintering birds. The morphology of the birds also varies between the sexes, and the sex of a Dunlin may often be difficult to determine. To clarify if mitochondrial DNA can be used to identify which breeding areas migrating Dunlin come from, we investigated the occurrence of different mtDNA haplotypes in Dunlin from eight breeding areas on the Russian and Siberian tundra. Four haplotypes were found and at most sites more than one haplotype occurred. The European haplotype predominated in the area west of the Taymyr Peninsula, the Siberian haplotype in central Siberia (from the Taymyr Peninsula to the Lopatka Peninsula) and the Beringian haplotype in eastern Siberia. One individual of an Alaskan haplotype, not detected previously among breeding birds outside North America, was found on Wrangel Island. The sex of each bird was identified genetically and the morphology of males and females was analysed separately. Birds with the European haplotype were generally smaller than birds with the Beringian or Alaskan haplotypes. Birds possessing the Siberian haplotype showed intermediate values in most cases. After compensating for differences between sites, males with the Siberian haplotype had significantly longer bills than males having the European haplotype. Multiple regressions indicate that mitochondrial DNA analysis improves models estimating the breeding origin of migrating Dunlin.
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| 10. |
- Wennerberg, Liv
(författare)
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Genetic Variation and Migration of Waders
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The migratory behaviour of birds has received much scientific interest, though many questions still remain unsolved. One of the reasons for this is the difficulty of following the birds as they move between breeding and wintering localities. Populations may mix on migration and the origin of individual birds is difficult to assess. One way to address this problem may be to develop genetic population markers, using molecular genetic analysis to estimate the breeding origin of the birds, and thereby making it possible to recognise them throughout the annual cycle. In this thesis, the genetic variation in three wader species is studied: Dunlin (Calidris alpina), Curlew Sandpiper (C. ferruginea) and White-rumped Sandpiper (C. fuscicollis). Waders are among the most long-distance migrants and often travel many thousands of kilometres every spring and autumn. The genetic variation within these species is described mainly using two molecular genetic methods: DNA-sequencing and microsatellite analysis. In the Dunlin, the mitochondrial control region shows clear geographic structuring on a global geographic scale, however some overlap also exists between populations. Geographic structuring is also found by microsatellites, which show more variation and also indicate genetic differences between populations on a local scale. Genetic markers are applied in two studies of the migration strategies of Dunlin, showing a parallel migration system, estimating the migration distances, and showing variation within the species in the timing of breeding, migration and moult. The Curlew Sandpiper, on the other hand, shows almost no geographic structuring and seems to have extremely low genetic differentiation between the two extreme flyways to West Africa and Australia respectively. Also the White-rumped Sandpiper shows genetic similarities between distant breeding areas. The low levels of genetic variation and population structuring in high arctic waders may be related to the influence of the glacial cycles on the breeding habitat, as well as to their migration strategies. Another method for identifying the origin of migrating birds may be to use of isotope analysis. White-rumped Sandpipers from different breeding grounds had different carbon isotopes ratios in the feathers, thus isotope analysis make it possible to distinguish them also on migration.
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| 11. |
- Wennerberg, Liv, et al.
(författare)
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Geographical variation and population structure in the White-rumped Sandpiper Calidris fuscicollis as shown by morphology, mitochondrial DNA and carbon isotope ratios
- 2002
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 1432-1939 .- 0029-8549. ; 131:3, s. 380-390
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Tidskriftsartikel (refereegranskat)abstract
- We studied the population structure of a high arctic breeding wader bird species, the White-rumped Sandpiper Calidris fuscicollis. Breeding adults, chicks and juveniles were sampled at seven localities throughout the species' breeding range in arctic Canada in 1999. The mitochondrial control region was analysed by DNA sequencing, feathers were analysed for carbon isotope ratios (C-13/C-12) by isotope ratio mass spectrometry, and morphological measurements were analysed using principal component analyses. taking the effect of sex into account (identified by molecular genetic methods). In general. our results support the notion that the White-rumped Sandpiper is a monotypic species with no subspecies, and most of the morphological and genetic variation occurs within sites. Nevertheless. some differences between sites were found. Birds from the two northernmost sites (Ellesmere and Devon Islands) had relatively longer bill and wing and shorter tarsus than birds sampled further south, possibly reflecting genetic differences between populations. The carbon isotope ratios were higher at the easternmost site (Baffin Island), revealing differences in the isotope content of the food. The mtDNA sequences showed no significant differentiation between sites and no pattern of isolation-by-distance was found. Based on the mtDNA variation, the species was estimated to have a long-term effective population size of approximately 9,000 females. The species shows no clear evidence of any population expansion or decline. Our results indicate that carbon isotope ratios, and possibly also certain mtDNA haplotypes, may be useful as tools for identifying the breeding origin of White-rumped Sandpipers on migration and wintering sites.
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