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Lifjeld J.T.,University of Oslo | Marthinsen G.,University of Oslo | Myklebust M.,Norwegian Ornithological Society | Dawson D.A.,University of Sheffield | Johnsen A.,University of Oslo
Journal of Ornithology | Year: 2010

We present photographic and molecular evidence of a wild Marsh Warbler × Sedge Warbler (Acrocephalus palustris × A. schoenobaenus) hybrid that occurred over three breeding seasons (2007-2009) near Trondheim, Central Norway. The bird had the appearance of a Marsh Warbler but with some typical Sedge Warbler plumage traits. DNA analyses of a few plucked body feathers, using the COI barcode region (mtDNA) and conserved microsatellite loci, confirmed that the bird was a hybrid, with a Marsh Warbler mother and a Sedge Warbler father. © 2009 Dt. Ornithologen-Gesellschaft e.V.

Ruokonen M.,University of Oulu | Aarvak T.,Norwegian Ornithological Society | Chesser R.K.,Texas Tech University | Lundqvist A.-C.,Uppsala University | MerilA J.,University of Helsinki
Molecular Ecology | Year: 2010

In small and declining populations levels of genetic variability are expected to be reduced due to effects of inbreeding and random genetic drift. As a result, both individual fitness and populations' adaptability can be compromised, and the probability of extinction increased. Therefore, maintenance of genetic variability is a crucial goal in conservation biology. Here we show that although the level of genetic variability in mtDNA of the endangered Fennoscandian lesser white-fronted goose Anser erythropus population is currently lower than in the neigbouring populations, it has increased six-fold during the past 140 years despite the precipitously declining population. The explanation for increased genetic diversity in Fennoscandia appears to be recent spontaneous increase in male immigration rate equalling 0.56 per generation. This inference is supported by data on nuclear microsatellite markers, the latter of which show that the current and the historical Fennoscandian populations are significantly differentiated (FST = 0.046, P = 0) due to changes in allele frequencies. The effect of male-mediated gene flow is potentially dichotomous. On the one hand it may rescue the Fennoscandian lesser white-fronted goose from loss of genetic variability, but on the other hand, it eradicates the original genetic characteristics of this population. © 2010 Blackwell Publishing Ltd.

Ruokonen M.,University of Oulu | Aarvak T.,Norwegian Ornithological Society
Ardea | Year: 2011

Taxonomic practices change over time and this affects the number of taxonomical units recognized. In late 19th and early 20th centuries the number of species increased as a consequence of typological thinking, i.e. classifying all aberrant individuals to a separate species. During this period, several species or subspecies of the bean goose complex were described, and currently their status is either considered not valid or is not agreed upon. We studied individuals from five of the historical taxa, Anser neglectus, A. mentalis, A. oatesi, A. fabalis johanseni and A. fabalis curtus, by using mitochondrial DNA and morphological measurements to clarify their taxonomical status. Overall, we did not find support for additional taxa other than those currently recognized.

Solheim R.,Agder Natural History Museum and Botanical Garden | Jacobsen K.-O.,Norwegian Institute for Nature Research | Oien I.J.,Norwegian Ornithological Society | Aarvak T.,Norwegian Ornithological Society | Polojarvi P.,Metsahallitus
Ornis Norvegica | Year: 2013

Blackflies (Simuliidae) have been shown to influence birds negatively in several ways. In 2011, during a peak lemming year, we found that two of 28 nests of Snowy Owls Bubo scandiacus in Northern Norway and Finland failed due to blackfly attacks on the incubating female. The observations also suggest that adult survival may be influenced by these insects. The owls' choice of breeding habitat can be decisive in their vulnerability to blackflies.

De Jong A.,Swedish University of Agricultural Sciences | Heinicke T.,International Bean Goose Project | Aarvak T.,Norwegian Ornithological Society | Oien I.J.,Norwegian Ornithological Society
Ornis Norvegica | Year: 2013

Based on 1420 neck-band reports we could map the movements of Tundra Bean Geese marked in northern Scandinavia. With few exceptions, the maps show a distinct migration pattern through Sweden to the main wintering area in NE Scania. In mild winters, only a few individuals extend their migration into continental Europe, but during severe winters, a large proportion of the sightings are from Germany and Denmark.

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