| 1. |
- Amininasab, Seyed Mehdi, et al.
(author)
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Effect of tree logging on reproductive performance in Blue Tits (Cyanistes caeruleus)
- 2017
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In: Journal of Ornithology = Journal fur Ornithologie. - : SPRINGER. - 0021-8375 .- 1439-0361. ; 158:1, s. 339-344
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Journal article (peer-reviewed)abstract
- For birds, habitat quality is largely determined by local vegetation, and reproductive performance can therefore be negatively influenced by anthropogenic activities. A tree logging event enabled us to examine the effect of removing trees of different maturities and types on the reproductive performance of Blue Tits (Cyanistes caeruleus). Against expectations, only the logging of small coniferous trees, but not larger and deciduous trees, was associated with a reduction in the number of eggs laid, whereas logging had no significant effect on lay date. Therefore, we conclude that modest logging activity has no or limited negative influence on Blue Tit reproductive performance.
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| 2. |
- Arzel, Céline, et al.
(author)
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A flyway perspective on food resource abundance in a long-distance migrant, the Eurasian teal (Anas crecca)
- 2009
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In: Journal of Ornithology = Journal fur Ornithologie. - 0021-8375 .- 1439-0361. ; 150:1, s. 61-73
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Journal article (peer-reviewed)abstract
- Two frequent assumptions about the evolution of long-distance migration in birds are that they travel long distances annually to reach food-rich areas for breeding, and that they time their migratory journey to be at staging sites when the latter provide the best feeding conditions. These assumptions have rarely been properly tested, and there is no study in which a species’ major food types have been measured by standardized methods throughout a flyway and over a large part of the year. We here present such data for Eurasian teal (Anas crecca), converted to a common energetic currency, and collected at wintering, spring staging and breeding sites. Teal did not time migration to maximize local food abundance; most birds left wintering and spring staging sites before a sharp increase in invertebrate food abundance occurred. On the other hand, hatching of ducklings coincided with a peak in invertebrate food abundance on boreal breeding lakes. Mean overall food abundance (invertebrates and seeds combined) did not differ between wintering sites in southern France and breeding sites in northern Sweden at the time of breeding. Our results are inconsistent with the hypothesis that long-distance migration in dabbling ducks has evolved because adult birds gain an immediate pay-off in increased food abundance by flying north in spring. However, our data confirm a selective advantage for breeding at higher latitudes, because hatching of ducklings may coincide with a peak in invertebrate emergence and because longer days may increase the duration of efficient foraging.
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| 3. |
- Arzel, Céline, et al.
(author)
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Ecology of spring-migrating Anatidae : a review
- 2006
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In: Journal of Ornithology = Journal fur Ornithologie. - 0021-8375 .- 1439-0361. - 0021-8375 ; 147:2, s. 167-184
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Research review (peer-reviewed)abstract
- Spring migration is generally considered as a crucial period of the year for many birds, not the least due to its supposed importance for subsequent breeding success. By reviewing the existing literature for Anatidae (ducks, geese, and swans), we show that little is known about their ecology in spring, although some goose species are exceptions. Another general pattern is that the ecology of Anatidae at staging sites is particularly neglected. Existing studies tend to focus on questions dealing with acquisition of nutrient reserves, whereas almost nothing has been published about stopover habitats, time use, microhabitat use, foraging behaviour, food availability, food limitation, diet selection, and interspecific relationships. Besides summarising present knowledge, we identify taxonomic groups and topics for which gaps of knowledge appear the most evident, thereby also highlighting research needs for the future.
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| 4. |
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| 5. |
- Corrales, Carolina, et al.
(author)
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Maintenance of gene flow by female-biased dispersal of black grouse, Tetrao tetrix in northern Sweden
- 2012
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 153:4, s. 1127-1139
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Journal article (peer-reviewed)abstract
- Sex-biased dispersal is a common phenomenon in most birds. In general, males breed at or near their site of birth while most of the females disperse. We investigated the dispersal patterns and genetic structure of lekking Black Grouse Tetrao tetrix based on ten microsatellite loci. Data for 469 individuals from 25 localities spaced from 45 to 558 km apart revealed low levels of genetic differentiation and high connectivity among studied sites due to female-biased dispersal. The spatial distribution of the genetic variation did not follow an isolation by distance pattern neither for females nor for males. STRUCTURE identified three clusters of male individuals but without any geographical pattern. Only one cluster was identified for females. Several tests of sex-biased dispersal were executed. Most of them showed no difference between sexes, but the mean assignment index and F IS showed a statistically significant female-biased dispersal. Therefore, we consider that the northern Swedish Black Grouse population is a panmictic population. The amount of gene flow throughout time has been consistent with dispersal and with no strong effect of forest fragmentation in the region.
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| 6. |
- Corrales, Carolina, et al.
(author)
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Phylogeography and subspecies status of Black Grouse
- 2014
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 155:1, s. 13-25
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Journal article (peer-reviewed)abstract
- The cold periods of the Pleistocene have had a striking impact on the diversification of most organisms in temperate regions. Phylogeographic patterns and postglacial expansion are poorly understood in the Black Grouse (Tetrao tetrix). This species is widely distributed across Eurasia, and has been divided into a number of subspecies on the basis of morphological differences and geographic isolation. To investigate the evolutionary history of the species, 143 samples from different regions were examined for a mtDNA control region fragment. Overall, analyses of mtDNA gave support for the divergence between Tetrao tetrix tetrix, T. t. ussuriensis and T. t. mongolicus. The analyses reveal the effects of colonisation out of glacial refugia on the genetic diversity and genetic structure of Black Grouse. The phylogeographical results are consistent with a demographic population expansion following a bell-shaped mismatch distribution, a star-shaped phylogeny and low nucleotide diversity. Patterns of postglacial dispersal imply that Black Grouse from southern Europe have been restricted to this area, and did not contribute to the genetic diversity of northern Europe. Instead, Black Grouse spread out to northern Europe from a refugium in the east and a possible one in western Europe, following the retreat of glacial ice sheets, although both refugia remain unidentified. We suggest that T. t. britannicus and T. t. viridanus correspond to northern T. t. tetrix, and that this lineage has diverged from the other subspecies. This division is tentative due to limited sampling, but it will facilitate the management of different evolutionary significant units of the species.
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| 7. |
- Doligez, Blandine, et al.
(author)
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Estimation and comparison of heritability and parent-offspring resemblance in dispersal probability from capture-recapture data using different methods : the Collared Flycatcher as a case study
- 2012
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 152, s. S539-S554
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Journal article (peer-reviewed)abstract
- Understanding the evolution of a trait requires analysing its genetic basis. Many studies have therefore estimated heritability values of different traits in wild populations using quantitative genetic approaches on capture-recapture data of individuals with known parentage. However, these models assume perfect individual detection probability, a hidden hypothesis that is rarely met in natural populations. To what extent ignoring imperfect detection may bias heritability estimates in wild populations needs specific investigation. We give a first insight into this question using dispersal probability in a patchy population of Collared Flycatchers Ficedula albicollis as an example. We estimate and compare heritability and parent-offspring resemblance in dispersal obtained from (1) quantitative genetic approaches ("classical'' parent-offspring regressions and more recent animal models) and (2) multi-state capture-recapture models accounting for individual detection probability. Unfortunately, current capture-recapture models do not provide heritability estimates, preventing a full comparison of results between models at this stage. However, in the study population, detection probability may be expected to be lower for dispersing compared to philopatric individuals because of lower mating/breeding success and/or higher temporary emigration, making the use of capture-recapture models particularly relevant. We show significant parent-offspring resemblance and heritable component of between-patch dispersal probability in this population. Accounting for imperfect detection does however not seem to influence the observed pattern of parent-offspring resemblance in dispersal probability, although detection probability is both sensibly lower than 1 and heterogeneous among individuals according to dispersal status. We discuss the problems encountered, the information that can be derived from, and the constraints linked to, each method. To obtain unbiased heritability estimates, combining quantitative genetic and capture-recapture models is needed, which should be one of the main developments of capture-recapture models in the near future.
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| 8. |
- Elmberg, Johan, 1960-, et al.
(author)
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Interpreting seasonal range shifts in migratory birds : a critical assessment of 'short-stopping' and a suggested terminology
- 2014
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In: Journal of Ornithology = Journal fur Ornithologie. - 0021-8375 .- 1439-0361. ; 155:3, s. 571-579
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Research review (peer-reviewed)abstract
- The term 'short-stopping' is increasingly used in ecology to describe spatio-temporal changes in occurrence of migratory species. Spurred by the insight that it has been used in a variety of contexts, we reviewed its use in avian ecology. A literature search yielded 59 papers explicitly treating short-stopping in birds, most of them in peer-reviewed journals. The term was first used in 1967 to describe a northward shift in wintering Canada Geese in North America and has been used with increasing frequency to the present day. Geese dominate the short-stopping literature, which is confined to the northern hemisphere. Short-stopping has been used to describe (1) a shortened autumn migration that results in a wintering distribution closer to breeding areas, (2) a shortened spring migration that results in a breeding distribution closer to wintering areas, and (3) a delay in autumn migration that leads to a perceived reduced abundance in some part of the winter range. We advocate that short-stopping should be used only to describe (1) range shifts that involve shortening of the migratory corridor, and that they are qualified explicitly by season (i.e. breeding/winter) and degree (i.e. full or partial range shift). In other cases of breeding, wintering or entire range shifts where the migratory corridor is elongated or remains the same, we recommend using the term 'range shift', qualified by season, geography and orientation (i.e. the direction of the range shift). We also discuss the need for spatially explicit avian count monitoring mechanisms (rather than capture-recapture or hunting bag data) designed specifically to track such changes in distribution in the future.
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| 9. |
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| 10. |
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| 11. |
- Fjeldså, Jon, et al.
(author)
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Molecular data reveal some major adaptational shifts in the early evolution of the most diverse avian family, the Furnariidae
- 2005
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 146:1, s. 1-13
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Journal article (peer-reviewed)abstract
- A robust phylogeny estimate for the family Furnariidae (sensu lato) was obtained using sequences of two nuclear introns and one mitochondrial gene (cyt b). Contrary to the widely accepted sister-group relationship of ovenbirds (Furnariinae) and woodcreepers (Dendrocolaptinae), a basal clade is suggested for Sclerurus and Geositta, while Xenops, hitherto considered an aberrant ovenbird, was found to occupy a basal position on the woodcreeper lineage. The morphological variation is re-interpreted in view of this revised phylogenetic hypothesis. Presumably, the remarkable adaptive radiation in this family started as primitive, Sclerurus-likes forms, which used the tail as a prop during terrestrial feeding, lured up to seek food on tree-trunks. The two basal woodcreeper genera, Xenops and then Glyphorynchus, show strong cranial specializations for hammering in wood, thus presenting a remarkable parallelism with the family Picidae, Xenops resembling a piculet, Glyphorynchus, a diminutive woodpecker. However, this specialization was lost in other woodcreepers, which show a more normal passerine skull, adapted for probing and prying in tree-trunk crevices and sallying for escaping insects. The ovenbirds developed a more flexible (rhynchokinetic) bill, well suited for probing and retrieving hidden prey in dead-leaf clusters and debris suspended in the vegetation, and in epiphyte masses. Adaptations to live in open terrain are secondary.
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| 12. |
- Guillemain, Matthieu, et al.
(author)
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Risky foraging leads to cost-free mate guarding in male teal Anas crecca
- 2007
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In: Journal of Ornithology = Journal fur Ornithologie. - 0021-8375 .- 1439-0361. - 0021-8375 ; 148:2, s. 251-254
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Journal article (peer-reviewed)abstract
- Mate guarding by males is common in species with long-lasting pair bonds. We tested if the need to guard females affected foraging depth in male teal (Anas crecca), and if they were more vigilant than females when foraging with submerged eyes (preventing monitoring of competing males and predators). These predictions were not supported, suggesting that foraging depth selection is primarily driven by other factors, presumably food related. A likely reason why deeply foraging males did not increase vigilance is that 37.5% of the foraging time was already dedicated to it. The apparent lack of guarding costs in foraging male teal may explain why such small ducks can maintain pair bonds for up to 7 months.
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| 13. |
- Haase, Martin, et al.
(author)
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Shallow genetic population structure in an expanding migratory bird with high breeding site fidelity, the Western Eurasian Crane Grus grus grus
- 2019
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 160, s. 965-972
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Journal article (peer-reviewed)abstract
- For more than half a century, the Western Eurasian Crane (Grus grus grus) has been expanding its range toward western Europe, recolonizing areas where it had been previously driven to extinction, including the UK, the Netherlands and Denmark. The Western Eurasian Crane is, on the one hand, a very mobile, migratory species, but on the other, is territorial and shows high breeding site fidelity. Hence, its genetic population structure is subject to antagonizing forces, which have different consequences. Based on the genotyping of six highly variable microsatellite loci, we inferred the population structure of the Western Eurasian Crane from samples from eight regions. We integrated classic F-statistics including analyses of molecular variance with a priori designation of structure and divisive clustering approaches, i.e. a Bayesian procedure (STRU CTU RE) and discriminant analysis of principal components, which infer structure a posteriori. According to the F-statistics, populations were only weakly differentiated, and the majority of the genetic variance (> 90%) was attributed to individuals. At first glance, the divisive approaches appeared to agree in finding four clusters. Yet, there was no correspondence regarding the composition of the clusters and none of the results were biologically meaningful. However, STRU CTU RE delivered an alternative interpretation, designating the highest likelihood to a scenario without subdivision, in clear agreement with the findings based on the F-statistics. In conclusion, the Western Eurasian Crane is genetically largely homogeneous, probably as a consequence of the rapid growth and range expansion of its population.
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| 14. |
- Hansson, Bengt, et al.
(author)
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Molecular evidence of a reed warbler x great reed warbler hybrid (Acrocephalus scirpaceus x A-arundinaceus) in Belgium
- 2004
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In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7206 .- 0021-8375 .- 1439-0361. ; 145:2, s. 159-160
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Journal article (peer-reviewed)abstract
- We report on the second case of a reed warbler x great reed warbler hybrid (Acrocephalus scirpaceus and A. arundinaceus). The bird was captured during a standardised ringing session in Belgium in autumn 1999, and fell between the parental species in all measurements. Molecular analyses of two microsatellite loci verified that the bird was a female that had a reed warbler father and a great reed warbler mother.
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| 15. |
- Hartman, Göran, et al.
(author)
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Trends and population dynamics of a Velvet Scoter (Melanitta fusca) population : influence of density dependence and winter climate
- 2013
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 154:3, s. 837-847
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Journal article (peer-reviewed)abstract
- As many seaduck populations around the world have been reported to be in decline, there is an increasing demand for knowledge about intrinsic and extrinsic factors determining population dynamics of these species. In this study, we analyzed long-term dynamics of the summer population of Velvet Scoters (Melanitta fusca) breeding in the Aland archipelago in the Baltic Sea; in particular, we examined the influence of winter weather and density dependence on population change. The studied population exhibited substantial fluctuations but only a weak negative trend during the total period of 58 years (1949-2007), and no significant trend at all during the latter three decades of the study (1977-2007). We tested for density dependence and incorporated the winter North Atlantic Oscillation index into the model to test for effects of winter conditions. Our final model explained 56.3 % of the variance of population growth of the studied population. Delayed density dependence explained 29.7 %, pre-breeding climate 8.3 %, and post-breeding climate 18.3 % of the variance. That breeding success is density dependent in a delayed manner is in accordance with the apprehension that Velvet Scoters breed at the age of 2 years. We conclude that density dependence and winter conditions must be taken into consideration when discussing population changes in seaducks in general and the Velvet Scoter in particular.
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| 16. |
- Hasselquist, Dennis
(author)
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Comparative immunoecology in birds: hypotheses and tests
- 2007
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In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7192 .- 0021-8375 .- 1439-0361. ; 148:Supplement 2, s. 571-582
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Research review (peer-reviewed)abstract
- In this review, I focus on three key questions in avian comparative immunoecology: variation in immune responses in relation to sex; latitude (and pace-of-life); and the annual cycle. I present hypotheses and evaluate the so far rather scanty and heterogenic data to test them. Sex differences in immune responses have been hypothesized to be caused by inferior immune responses in the heterogametic sex (females in birds), sexual selection (males invest more in mate acquisition and less in immune function compared to females under polygyny, whereas the sexes invest equally in immune function under monogamy), or body size differences. Available data refute the heterogametic sex hypothesis, but tentatively support the sexual selection hypothesis. Latitudinal patterns of immune responses have been hypothesized to be adjusted to parasite pressure, pace-of-life or breeding season stress. In passerine birds, species breeding closer to the equator (where parasites presumably are more abundant) tended to show stronger humoral but not cell-mediated immune responses. Annual patterns of immune responses could be related to melatonin levels or adjusted to seasonal differences in parasite exposure (high exposure in tropical migrants in winter and in temperate breeding birds in summer). The results from studies of immune responses over the annual cycle in birds show no clear pattern over the annual cycle and there is little consistency between different components of the immune system. Clearly, to facilitate further testing of these intriguing ideas in comparative immunoecology, more studies on non-domesticated birds are needed.
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| 17. |
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| 18. |
- Hasselquist, Dennis, et al.
(author)
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Temporal patterns of occurrence and transmission of the blood parasite Haemoproteus payevskyi in the great reed warbler Acrocephalus arundinaceus
- 2007
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 148:4, s. 401-409
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Journal article (peer-reviewed)abstract
- We studied the prevalence and intensity of the haemosporidian blood parasite Haemoproteus payevskyi in great reed warblers at Lake Kvismaren (6 years) and Lake Segersjo (3 years) in Sweden. Based on microscopic inspection of slides from 282 adult birds, 20.6% showed infection of H. payevskyi in circulating red blood cells in at least 1 year. For parasite prevalence, there was no difference between years, sex, and age classes. However, parasite intensity was higher in females than in males, and this was most pronounced in 1-year-old birds. Individuals scored to carry parasites in year (n) were more likely to show parasite infection year (n + 1) than birds scored to be parasite-free in year (n) . None of 99 juvenile birds examined at the breeding site in late summer, 4-9 weeks after hatching, showed infection of H. payevskyi. Parasite intensity in infected adult birds decreased in the course of the breeding season and no new or relapse infections were observed during this period. Thus, our data imply that in the great reed warbler, a long-distance migrant to tropical Africa, transmission of H. payevskyi occurs on wintering sites or at stopover sites during migration.
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| 19. |
- Helander, Björn, 1946-, et al.
(author)
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Morphological and genetic sex identification of white-tailed eagle Haliaeetus albicilla nestlings
- 2007
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 148:4, s. 435-442
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Journal article (peer-reviewed)abstract
- Identifying the sex of bird nestlings is relevant to studies of behaviour and ecology and is often a central issue in the management of endangered or captive populations. The white-tailed eagle Haliaeetus albicilla is a formerly threatened Eurasian raptor which is closely monitored in many countries due to its high exposure to environmental pollutants in the food chain. The aim of this study was to evaluate the reliability of sex identification methods for white-tailed eagle nestlings based on morphological measurements that can be recorded at the nest by a single person and with minimum disturbance. The sex of each bird was independently determined using molecular (genetic) methods. One measure of tarsus width allowed the correct identification of sex for 96% of the nestlings from southern and central Sweden. However, we found that the criteria for sex identification were not directly applicable to the population in Swedish Lapland, where nestlings are typically thinner, probably due to a limited food supply. These results show that sexing in the field of white-tailed eagle nestlings can be feasible with high accuracy based on a limited number of measurements. However, the criteria employed to separate sexes may have to be adjusted for each population.
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| 20. |
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| 21. |
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| 22. |
- Hoglund, Jacob, et al.
(author)
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A hybrid snipe Gallinago gallinago x G-media found in the wild
- 2015
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 156:3, s. 819-827
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Journal article (peer-reviewed)abstract
- A hybrid snipe male was observed and caught in 2009 in the Norwegian mountains. We report behaviour, vocalizations, morphology, and genetic data for this bird. Mitochondrial and nuclear DNA sequences revealed that the hybrid had a great snipe mother and a common snipe father. The hybrid was intermediate in most measured morphometric traits and showed some intermediate plumage characteristics. The behaviour was similar to that of a great snipe-it displayed and vocalised at a great snipe lek for more than a week. The song was somewhat reminiscent of a great snipe's, but lacked the frequency-modulated whistles that are part of the great snipe song, consisting of more rapid click notes of a narrower frequency spectrum. This is the only putative hybrid that we have found among the more than 4,400 adult individuals we have examined between 1986 and 2014 at great snipe leks in Norway, Sweden, Poland, and Estonia. Common snipes invariably occur near these sites. Reports on putative hybrids among snipe species are very rare, and we question the validity of previous claims. This is the first where the parental origins-and, indeed, the hybrid status-have been unequivocally determined. We speculate on how a great snipe female, known for being extremely choosy about mating, came to mate with a common snipe male. We also note that, although perhaps behaviourally more likely, physical constraints on chick development (caused by the smaller egg size of the common snipe and larger body size of the great snipe) might prevent any successful male great snipe x female common snipe hybridisation-a possible example of an unidirectional post-zygotic barrier.
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| 23. |
- Höglund, Jacob, et al.
(author)
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Phylogeography of the Black-tailed Godwit Limosa limosa : substructuring revealed by mtDNA control region sequences
- 2009
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 150:1, s. 45-53
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Journal article (peer-reviewed)abstract
- Black-tailed (Limosa limosa) and Hudsonian Godwits (L. haemastica) are sometimes described as a superspecies. The Black-tailed Godwit is further split into three subspecies on the basis of morphological differences ( L. l. limosa, L. l. islandica and L. l. melanuroides). We studied variation in partial mtDNA control region sequences among Black-tailed and Hudsonian Godwits which showed 5% divergence. Black-tailed and Hudsonian Godwits were thus clearly differentiated and the separate species status for the two taxa is validated. All three subspecies described for the Black-tailed Godwit had unique haplotypes but the genetic distances were small (0.3-0.6%). Despite small genetic differences we could not detect any substantial gene flow between any of the subspecies as haplotypes were private to each subspecies. Thus, genetic variation within Black-tailed Godwits showed a clear geographic structure. We found a high proportion of rare private haplotypes in three fringe populations of the nominate subspecies of the Black-tailed Godwit (L. l. limosa) where godwits breed in low numbers, but no genetic variation at all in a sample from the Netherlands where godwits are abundant. This suggests that Dutch Godwits may have been affected by a founder effect.
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| 24. |
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| 25. |
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| 26. |
- Muheim, Rachel, et al.
(author)
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Magnetic compass of migratory Savannah sparrows is calibrated by skylight polarizarion and sunrise and sunset
- 2007
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In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7206 .- 0021-8375 .- 1439-0361. ; 148:Supplement 2, s. 485-494
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Journal article (peer-reviewed)abstract
- Migratory birds use compass systems derived from the geomagnetic field, the stars, the sun and polarized light patterns. We tested whether birds use a single underlying reference system for calibration of these compasses and, specifically, whether sunset and sunrise polarized light cues from the region of the sky near the horizon are used to calibrate the magnetic compass. We carried out orientation experiments with Savannah sparrows, Passerculus sandwichensis, in Alaska during autumn migration 2005, and compared the magnetic orientations of individual birds before and after exposure to conflicting information between magnetic and celestial cues. Birds exposed to an artificially shifted polarization pattern (±90° shift relative to the natural condition) for 1 h at local sunrise or sunset recalibrated their magnetic compass, but only when given access to the artificial polarization pattern near the horizon. Birds exposed to a 90° clockwise-shifted magnetic field for 1 h at solar noon did not recalibrate their magnetic compass. These results indicate that migratory birds calibrate their magnetic compass using the skylight polarization pattern vertically intersecting the horizon at sunrise and sunset. In conjunction with earlier work showing that sun and star compass calibrations are secondarily derived from magnetic and polarized light cues, our findings suggest that polarized light cues near the horizon at sunrise and sunset provide the primary calibration reference for the compass systems of migratory songbirds.
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| 27. |
- Navedo, Juan G., et al.
(author)
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Long-distance travellers stopover for longer : a case study with spoonbills staying in North Iberia
- 2010
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 151:4, s. 915-921
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Journal article (peer-reviewed)abstract
- Long-distance migration is widespread among birds, connecting breeding and wintering areas through a set of stopover localities where individuals refuel and/or rest. The extent of the stopover is critical in determining the migratory strategy of a bird. Here, we examined the relationship between minimum length of stay of PVC-ringed birds in a major stopover site and the remaining flight distance to the overwintering area in the Eurasian spoonbill (Platalea l. leucorodia) during four consecutive autumn migrations. We also analysed the potential effect of timing (arrival date), as well as the role of experience in explaining stopover duration of spoonbills. Overall, birds wintering in Africa, and facing long-distance travel from the stopover site (ca. 3,000 km) stay for longer (2.7 +/- A 0.4 days) than Iberian winterers (1.5 +/- A 0.2 days) that perform a much shorter migration (ca. 800 km). These differences were consistent between years. Stopover duration was not significantly affected by the age of the bird. However, there was a significant reduction as migration advanced. Our results suggest that spoonbills develop different stopover strategies depending on the expected distance to the wintering grounds. Adults, especially long-distance migratory ones, could reduce the potential negative effects of density-dependence processes by avoiding stopover at the end of the migration period. These findings are of significant relevance for understanding differences in migratory behaviour within single populations, especially for declining waterbirds, as well as stress the relevance of preserving stopover localities for the conservation of intraspecific diversity in migratory species.
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| 28. |
- Podmokla, Edyta, et al.
(author)
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Determinants of prevalence and intensity of infection with malaria parasites in the Blue Tit
- 2014
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 155:3, s. 721-727
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Journal article (peer-reviewed)abstract
- Parasite species are usually specialists utilising specific host species, but parasite assemblages may differ substantially even between populations of the same species and show seasonal and annual fluctuations. Host characteristics such as individual age and sex may also affect parasite species composition and abundance. Here, we report the occurrence of malaria parasites in the Blue Tit (Cyanistes caeruleus) inhabiting Gotland (Sweden) across 5 years. Using PCR-based techniques, we found eight cytochrome b lineages belonging to genus Plasmodium (pTURUD1, pBT7, pSGS1, pSW2, pGRW11) and Haemoproteus (hPARUS1, hPHSIB1, hWW2) with the overall prevalence of 65 %. The Plasmodium infections predominated (prevalence of 49.5 %), whereas Haemoproteus infection rate was much lower (prevalence of 16.5 %). We showed significant differences in infection status between study years and age classes when all parasite lineages were analysed together or the two most common lineages were analysed separately. Overall, older birds showed higher prevalence. A significant interaction between year and genus effect significantly explained variation in infection intensity. This interaction stems from a significant yearly variation of the infection intensity with Plasmodium, while such an effect is not present for Haemoproteus infections. More importantly, the intensity of infection with Haemoproteus was significantly higher than with Plasmodium in 3 out of the 4 study years with data.
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| 29. |
- Pöysä, Hannu, et al.
(author)
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Recovering Whooper Swans do not cause a decline in Eurasian Wigeon via their grazing impact on habitat
- 2018
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science Business Media. - 0021-8375 .- 1439-0361. ; 159, s. 447-455
-
Journal article (peer-reviewed)abstract
- The Whooper Swan (Cygnus cygnus) is a good example of successful conservation, with rapidly growing numbers in Fennoscandia in recent decades. To the contrary, Eurasian Wigeon (Mareca penelope) shows a strong negative trend in breeding numbers, which raises conservation concerns. Previous research suggests a causal link between recent population trajectories of the two species. Both preferentially breed on wetlands with abundant horsetail (Equisetum spp.), a plant providing food for Whooper Swan and crucial feeding microhabitat for Eurasian Wigeon broods. We here test predictions based on the hypothesis that grazing on Equisetum by Whooper Swan reduces breeding habitat or breeding habitat quality for Eurasian Wigeon. We use data from 60 lakes in which waterfowl were counted in 1990–1991 and 2016, and Equisetum was mapped in 1990–1991 and 2013–2014. Lakes colonized by Whooper Swan typically had more abundant Equisetum vegetation in the past than lakes not colonized. Lake-specific decrease of Equisetum was not associated with colonization by Whooper Swan. The number of lakes occupied by Eurasian Wigeon decreased, but the decrease was not stronger on lakes colonized by Whooper Swan than on those that were not. Contrary to our prediction, current Eurasian Wigeon abundance was positively associated with Whooper Swan abundance. Moreover, Eurasian Wigeon did not decrease more on lakes from which Equisetum disappeared than on lakes in which there was still Equisetum left. This study does not support the idea that Whooper Swan affects Eurasian Wigeon negatively by grazing on Equisetum.
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| 30. |
- Pöysä, Hannu, et al.
(author)
-
Recovering Whooper Swans do not cause a decline in Eurasian Wigeon via their grazing impact on habitat
- 2018
-
In: Journal of Ornithology. - : Springer Nature. - 0021-8375 .- 1439-0361 .- 2193-7192 .- 2193-7206. ; 159:2, s. 447-455
-
Journal article (peer-reviewed)abstract
- The Whooper Swan (Cygnus cygnus) is a good example of successful conservation, with rapidly growing numbers in Fennoscandia in recent decades. To the contrary, Eurasian Wigeon (Mareca penelope) shows a strong negative trend in breeding numbers, which raises conservation concerns. Previous research suggests a causal link between recent population trajectories of the two species. Both preferentially breed on wetlands with abundant horsetail (Equisetum spp.), a plant providing food for Whooper Swan and crucial feeding microhabitat for Eurasian Wigeon broods. We here test predictions based on the hypothesis that grazing on Equisetum by Whooper Swan reduces breeding habitat or breeding habitat quality for Eurasian Wigeon. We use data from 60 lakes in which waterfowl were counted in 1990–1991 and 2016, and Equisetum was mapped in 1990–1991 and 2013–2014. Lakes colonized by Whooper Swan typically had more abundant Equisetum vegetation in the past than lakes not colonized. Lake-specific decrease of Equisetum was not associated with colonization by Whooper Swan. The number of lakes occupied by Eurasian Wigeon decreased, but the decrease was not stronger on lakes colonized by Whooper Swan than on those that were not. Contrary to our prediction, current Eurasian Wigeon abundance was positively associated with Whooper Swan abundance. Moreover, Eurasian Wigeon did not decrease more on lakes from which Equisetum disappeared than on lakes in which there was still Equisetum left. This study does not support the idea that Whooper Swan affects Eurasian Wigeon negatively by grazing on Equisetum.
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| 31. |
- Segelbacher, Gernot, et al.
(author)
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Kin groups in closely spaced capercaillie leks
- 2007
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 148:1, s. 79-84
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Journal article (peer-reviewed)abstract
- We quantified the genetic structure among 58 capercaillie (Tetrao urogallus) from three closely spaced leks in boreal Russia using ten microsatellite loci. We did not find significant structuring with respect to lek membership in an overall analysis. However, all but one individual could be strongly assigned to one of two genetic clusters, which we interpret as reflecting different local lineages or extended family groups. There was evidence for structuring among some clusters within leks, and one smaller lek consisted of nine out of ten males from one cluster, which could reflect kin biasing of lek membership. One cluster was apparently outperforming the other, since nine out of ten juveniles sampled belonged to it.
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| 32. |
- Stach, Robert, 1971-, et al.
(author)
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Migration routes and timing in a bird wintering in South Asia, the Common Rosefinch Carpodacus erythrinus
- 2016
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7192 .- 2193-7206. ; 157, s. 671-679
-
Journal article (peer-reviewed)abstract
- Only few bird species from Western Europe migrate eastward to wintering areas in South Asia, and little is known about this migratory flyway. The Common Rosefinch has in the past century expanded its breeding range westward to include Western Europe and migrate along this flyway to wintering sites in South Asia. This is the first study describing the migration routes of Common Rosefinches between Europe and Asia in detail, revealed by light level geolocators. The rosefinches showed loop-migration with more northerly routes in autumn than in spring, possibly in order to shorten the flight over the Central Asian deserts, which are very inhospitable at this time of the year. In spring the deserts are less dry and richer in vegetation, which may have supported the more southerly routes. During autumn migration the birds used several staging sites in Central Asia for prolonged periods. Although the birds passed over mountain regions at this time, which potentially act as barriers to them, the length of the stops seem unrealistically long for only fuel deposition. Instead, this suggests that the birds temporarily suspended migration to take advantage of abundant and predictable food sources in this region. During spring migration the birds made a few longer stops while still in north India or Central Asia, before migrating at fast speeds towards the breeding grounds. The birds covered 4–5000 km with only very short stopovers and thus most of the fuel used on spring migration must have been accumulated in Asia. Our results thus indicate that Central Asia, and north India, are important staging areas for this species in both autumn and spring. During winter, birds used two sites located several hundred kilometres apart, and relocation was probably a response to local food availability.
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| 33. |
- Sudyka, Joanna, et al.
(author)
-
Longitudinal studies confirm faster telomere erosion in short-lived bird species
- 2016
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 157:1, s. 373-375
-
Journal article (peer-reviewed)abstract
- Evidence is accumulating that telomeres become shorter with advancing age and possibly explain some of the observed variation in longevity. Cross-sectional analyses have shown that species with shorter lifespans lose more telomeric repeats with age than species with longer lifespans. Using existing data from longitudinal studies performed on several bird species, we confirmed a negative relationship between the rate of telomere shortening and maximum longevity.
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| 34. |
- Svensson, Magnus, et al.
(author)
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Impaired hatching success and male-biased embryo mortality in Tree Sparrows
- 2007
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 148:1, s. 117-122
-
Journal article (peer-reviewed)abstract
- During the past 30 years, many species of farmland birds have declined dramatically in numbers in Northern Europe, a trend coinciding with a tremendous intensification of agriculture, although the exact causes of these declines remain unclear. One of the worst affected species is the Tree Sparrow (Passer montanus). We studied two Swedish Tree Sparrow populations during the years 1996–2004 and found that in both populations, almost half of all laid eggs remained unhatched. This led us to investigate whether the eggs failed to hatch because of: (1) eggs not being fertilised or (2) embryo mortality. Our analyses showed that all of the eggs investigated contained sufficient number of sperm for fertilisation and that they also had other visible signs indicating that fertilisation had occurred. Hatching failure was instead shown to result from embryo mortality. Using molecular techniques, we were able to determine that embryo mortality is more likely to affect male embryos than females and that the fledgling sex ratio was consequently highly female biased. The cause of this sex-biased embryo mortality remains unknown, but various potential explanations are discussed.
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| 35. |
- Svobodova, Jana, et al.
(author)
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Genetic variation in Black Grouse populations with different lekking systems in the Czech Republic
- 2011
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In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 152:1, s. 37-44
-
Journal article (peer-reviewed)abstract
- Here, we describe genetic diversity of lekking and non-lekking populations of Black Grouse Tetrao tetrix in the mountains bordering the Czech Republic. In total, 250 individuals from eight lekking and eight non-lekking study sites were genotyped at 11 microsatellite loci. Significant pair-wise F (ST) values between the different regions indicated low dispersal between localities, and birds could be assigned to three main mountain ranges (umava Mts, Krkonoe Mts and Krun, Mts). We found lower genetic diversity at study sites with solitary displaying males compared to sites where birds aggregate at leks. Additionally, genetic diversity was significantly more strongly associated with type of display than with spatial location of the sites. Given that lekking behaviour may be related to population density, we suggest that a shift from lekking to solitary displaying males is an alarming sign for conservationists indicating decreasing effective population sizes and declining populations.
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| 36. |
- Sztukowski, Lisa A., et al.
(author)
-
Tracking reveals limited interactions between Campbell Albatross and fisheries during the breeding season
- 2017
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer. - 0021-8375 .- 1439-0361. ; 158:3, s. 725-735
-
Journal article (peer-reviewed)abstract
- Fisheries-related mortality has been influential in driving global declines in seabird populations. Understanding the overlap between seabird distribution and fisheries is one important element in assessing bycatch risk, and may be achieved by tracking the movements of individual birds and fishing vessels. Here, we assess the spatiotemporal overlap between the vulnerable Campbell Albatross Thalassarche impavida and large (>28 m) commercial fishing boats in New Zealand’s Exclusive Economic Zone (EEZ). We used a novel analytical approach, bivariate Gaussian bridge movement modelling, to compute spatiotemporal utilization distributions of bird-borne global positioning system (GPS) loggers and data from the Vessel Monitoring System. We tracked birds for 28,815 h during incubation and chick brooding, with half of this time spent within New Zealand’s EEZ, utilizing 6.7% of the available area. However, there was no evidence that albatrosses and fishing vessels were in the same location simultaneously. We accounted for the broader ecological footprint of fishing vessels by calculating the distance between GPS-fix locations for albatrosses and fishing vessels, revealing that albatrosses were within 30 km of fishing vessels in 8.4% of foraging trips. This highlights differences in estimated fine-scale spatiotemporal overlaps which may be due to the distance between albatrosses and vessels or the methods used. Overall, the low levels of spatial overlap could be a result of Campbell Albatross’ preference for foraging in areas without fishing activity or competitive exclusion by other species. Our results reinforce the importance of multi-scale, temporally explicit, and multi-national approaches to risk assessment, as Campbell Albatrosses spend approximately half of their time foraging outside New Zealand’s EEZ.
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| 37. |
- Votier, S. C., et al.
(author)
-
Stable isotopes and mtDNA reveal niche segregation but no evidence of intergradation along a habitat gradient in the Lesser Whitethroat complex (Sylvia curruca; Passeriformes; Aves) ESZEN LL, 1983, OECOLOGIA, V57, P32
- 2016
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206 .- 1439-0361. ; 157:4, s. 1017-1027
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Journal article (peer-reviewed)abstract
- Niche segregation plays a critical role in the speciation process, but determining the extent to which taxa are geographically or ecologically isolated is challenging. In this study, we use stable isotopes of carbon (delta C-13), nitrogen (delta N-15), hydrogen (delta H-2) and oxygen (delta O-18) to test for ecological differences among taxa in the Lesser Whitethroat Sylvia curruca complex. Analysis of mitochondrial DNA (mtDNA) revealed 6 distinct haplotype groups, which conform to at least 5 distinct taxa. Stable isotopes provided insight into geographical and broad-scale ecological differences among haplotypes. The most striking isotope differences were between the populations inhabiting Siberian boreal forest (S. c. blythi) from the one inhabiting semi-desert in Kazakhstan (S. c. halimodendri). It is generally assumed that these two populations form a morphological cline along a gradient from mesic to xeric habitat. Our sample includes a large proportion of morphologically intermediate individuals that appear to represent a hybrid population. However, in all of these, there is strict correspondence between haplotype and isotope signature, suggesting an ecological division on the breeding grounds between all our samples of these two taxa. The lack of ecologically intermediate individuals among our sample of morphologically intermediate ones thus speaks against the existence of a cline. The two taxa blythi and halimodendri emerge as potential models for the study of the early stages of the speciation process. While differences in stable isotopes may be largely influenced by geography, we also demonstrate how, in specific instances (such as the alleged cline reported here), they may be used to evaluate niche segregation between taxa, providing information of importance for determination of species limits.
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| 38. |
- Westerdahl, Helena
(author)
-
Passerine MHC: genetic variation and disease resistance in the wild
- 2007
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7206 .- 0021-8375 .- 1439-0361. ; 148, s. 469-477
-
Journal article (peer-reviewed)abstract
- The passerine major histocompatibility complex (MHC) class I and IIB genes are different from those of the avian model species the chicken because passerines have (1) a larger number of MHC genes, (2) MHC genes with longer introns, and (3) MHC genes that are pseudo-genes. Most passerine MHC genes are transcribed (coding), extremely variable and subject to balancing selection. The high genetic diversity of the MHC genes of passerines is most likely maintained by selection from a large number of different pathogens. Association between MHC alleles and resistance to avian malaria infections have been reported in House Sparrows and Great Reed Warblers. Passerines are infected by a large number of different avian malaria infections. Therefore passerines and avian malaria is a study system that is well-suited to investigations of balancing selection and associations between MHC genes and disease resistance.
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| 39. |
- Zhao, M., et al.
(author)
-
Phylogenetic position of the Wallcreeper Tichodroma muraria
- 2016
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 1439-0361. ; 157:3, s. 913-918
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Journal article (peer-reviewed)abstract
- The Wallcreeper Tichodroma muraria is usually placed in a monotypic family or subfamily within the superfamily Certhioidea, with assumed close relationships to Certhia (treecreepers), Sitta (nuthatches) and Salpornis (spotted creepers). Previous studies have suggested that Tichodroma is most closely related to Sitta, alternatively to Salpornis. We analysed the relationships of Tichodroma using two mitochondrial and five nuclear loci. The tree based on concatenated sequences strongly supported a sister relationship between Tichodroma and Sitta, as well as between Salpornis and Certhia. However, species tree analysis (MP-EST) was unable to resolve these relationships, and although the concatenation tree remains the best hypothesis, more data are needed to corroborate this. © 2016, Dt. Ornithologen-Gesellschaft e.V.
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| 40. |
- Zhao, Min, et al.
(author)
-
Phylogenetic position of the Wallcreeper Tichodroma muraria
- 2017
-
In: Journal of Ornithology = Journal fur Ornithologie. - : SPRINGER. - 0021-8375 .- 1439-0361. ; 158:2, s. 629-630
-
Journal article (peer-reviewed)abstract
- The Wallcreeper Tichodroma muraria is usually placed in a monotypic family or subfamily within the superfamily Certhioidea, with assumed close relationships to Certhia (treecreepers), Sitta (nuthatches) and Salpornis (spotted creepers). Previous studies have suggested that Tichodroma is most closely related to Sitta, alternatively to Salpornis. We analysed the relationships of Tichodroma using two mitochondrial and five nuclear loci. The tree based on concatenated sequences strongly supported a sister relationship between Tichodroma and Sitta, as well as between Salpornis and Certhia. However, species tree analysis (MP-EST) was unable to resolve these relationships, and although the concatenation tree remains the best hypothesis, more data are needed to corroborate this.
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| 41. |
- Arzel, Céline, et al.
(author)
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A flyway perspective on food resource abundance in a long-distance migrant, the Eurasian teal (Anas crecca)
- 2009
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375. ; 150:1, s. 61-73
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Journal article (peer-reviewed)abstract
- Two frequent assumptions about the evolution of long-distance migration in birds are that they travel long distances annually to reach food-rich areas for breeding, and that they time their migratory journey to be at staging sites when the latter provide the best feeding conditions. These assumptions have rarely been properly tested, and there is no study in which a species’ major food types have been measured by standardized methods throughout a flyway and over a large part of the year. We here present such data for Eurasian teal (Anas crecca), converted to a common energetic currency, and collected at wintering, spring staging and breeding sites. Teal did not time migration to maximize local food abundance; most birds left wintering and spring staging sites before a sharp increase in invertebrate food abundance occurred. On the other hand, hatching of ducklings coincided with a peak in invertebrate food abundance on boreal breeding lakes. Mean overall food abundance (invertebrates and seeds combined) did not differ between wintering sites in southern France and breeding sites in northern Sweden at the time of breeding. Our results are inconsistent with the hypothesis that long-distance migration in dabbling ducks has evolved because adult birds gain an immediate pay-off in increased food abundance by flying north in spring. However, our data confirm a selective advantage for breeding at higher latitudes, because hatching of ducklings may coincide with a peak in invertebrate emergence and because longer days may increase the duration of efficient foraging.
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| 42. |
- Arzel, Céline, et al.
(author)
-
Ecology of spring-migrating Anatidae : a review
- 2006
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375. ; 147:2, s. 167-184
-
Research review (peer-reviewed)abstract
- Spring migration is generally considered as a crucial period of the year for many birds, not the least due to its supposed importance for subsequent breeding success. By reviewing the existing literature for Anatidae (ducks, geese, and swans), we show that little is known about their ecology in spring, although some goose species are exceptions. Another general pattern is that the ecology of Anatidae at staging sites is particularly neglected. Existing studies tend to focus on questions dealing with acquisition of nutrient reserves, whereas almost nothing has been published about stopover habitats, time use, microhabitat use, foraging behaviour, food availability, food limitation, diet selection, and interspecific relationships. Besides summarising present knowledge, we identify taxonomic groups and topics for which gaps of knowledge appear the most evident, thereby also highlighting research needs for the future.
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| 43. |
- Cardinale, Massimiliano
(author)
-
Effects of body condition and food intake on stop-over decisions in Garden Warblers and European Robins during spring migration
- 2017
-
In: Journal für Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206. ; 158, s. 989-999
-
Journal article (peer-reviewed)abstract
- During migration, birds need to optimize their time and/or energy management, especially during stop-overs. Previous studies with caged birds under controlled condition support the notion that departure decisions are condition-dependent, but they did not take into account the availability or the actual intake of food. In the study reported here we investigated whether food intake interacts with condition in influencing migratory disposition in temporarily caged wild migrants. We conducted the study on Garden Warblers (Sylvia borin) and European Robins (Erithacus rubecula) at a spring stop-over site that is reached after a long non-stop flight over the Mediterranean Sea. The birds were held in cages during the day and the first night following capture, and their locomotor activity, food intake, and body mass change were recorded. In both species, food intake was positively correlated with body mass change. Body condition was positively correlated with migratory restlessness (Zugunruhe) in both species and was also negatively related to diurnal activity in Garden Warblers. Food intake was negatively correlated with diurnal activity in Garden Warblers. When only birds with low fat scores were considered, we found a positive effect of food intake on Zugunruhe in Garden Warblers. In general, European Robins consumed less food than Garden Warblers and no significant effects on Zugunruhe were found. Our results show that food intake interacts with condition in affecting migratory behavior during stop-overs. In particular, food intake may induce Garden Warblers with low fat stores at arrival to leave a stop-over site earlier. The large individual variability in food consumption supports the notion that birds vary in their capacity to refuel soon after arrival at a stop-over site. Overall, our work suggests that the decision to stay at the stop-over site or to resume migration depends on the interaction of condition, refueling capacity and rate, and migratory strategy.
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| 44. |
- Elmberg, Johan, et al.
(author)
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Interpreting seasonal range shifts in migratory birds : a critical assessment of 'short-stopping' and a suggested terminology
- 2014
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375. ; 155:3, s. 571-579
-
Research review (peer-reviewed)abstract
- The term 'short-stopping' is increasingly used in ecology to describe spatio-temporal changes in occurrence of migratory species. Spurred by the insight that it has been used in a variety of contexts, we reviewed its use in avian ecology. A literature search yielded 59 papers explicitly treating short-stopping in birds, most of them in peer-reviewed journals. The term was first used in 1967 to describe a northward shift in wintering Canada Geese in North America and has been used with increasing frequency to the present day. Geese dominate the short-stopping literature, which is confined to the northern hemisphere. Short-stopping has been used to describe (1) a shortened autumn migration that results in a wintering distribution closer to breeding areas, (2) a shortened spring migration that results in a breeding distribution closer to wintering areas, and (3) a delay in autumn migration that leads to a perceived reduced abundance in some part of the winter range. We advocate that short-stopping should be usedonly to describe (1) range shifts that involve shortening of the migratory corridor, and that they are qualified explicitly by season (i.e. breeding/winter) and degree (i.e. full or partial range shift). In other cases of breeding, wintering or entire range shifts where the migratory corridor is elongated or remains the same, we recommend using the term 'range shift', qualified by season, geography and orientation (i.e. the direction of the range shift). We also discuss the need for spatially explicit avian count monitoring mechanisms (rather than capture-recapture or hunting bag data) designed specifically to track such changes in distribution in the future.
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| 45. |
- Enemar, Anders, 1926, et al.
(author)
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Early onset of reduced reproductive performance with age in the Treecreeper ( Certhia familiaris )
- 2008
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206. ; 149:1, s. 117-121
-
Journal article (peer-reviewed)abstract
- Reductions in reproductive performance with age have been predicted to result from a general deterioration of performance, i.e. senescence. Variation among species in the onset and rate of this deterioration depends on the age-independent extrinsic mortality rate. If few individuals reach a specific age, the strength of selection for mechanisms that retard senescence will be reduced. The aim of this study was to investigate the age-dependent variation in two reproductive traits in a species, the Treecreeper (Certhia familiaris), with a low between-year survival rate. Clutch size did not vary with age, but egg size decreased from the first to the second breeding season. Compared with published age-dependent reductions in egg size, Treecreepers demonstrate the earliest onset of senescence, but they also have the highest total mortality rate, corroborating the predictions from the evolutionary theory of senescence. Production of eggs seems to be demanding for female Treecreepers, as egg size is also positively dependent on ambient temperature, further stressing the vulnerability of this trait for small reductions in female performance.
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| 46. |
- Guillemain, Matthieu, et al.
(author)
-
Risky foraging leads to cost-free mate guarding in male teal Anas crecca
- 2007
-
In: Journal of Ornithology = Journal fur Ornithologie. - : Springer Science and Business Media LLC. - 0021-8375. ; 148:2, s. 251-254
-
Journal article (peer-reviewed)abstract
- Mate guarding by males is common in species with long-lasting pair bonds. We tested if the need to guard females affected foraging depth in male teal (Anas crecca), and if they were more vigilant than females when foraging with submerged eyes (preventing monitoring of competing males and predators). These predictions were not supported, suggesting that foraging depth selection is primarily driven by other factors, presumably food related. A likely reason why deeply foraging males did not increase vigilance is that 37.5% of the foraging time was already dedicated to it. The apparent lack of guarding costs in foraging male teal may explain why such small ducks can maintain pair bonds for up to 7 months.
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| 47. |
- Gunnarsson, Gunnar, et al.
(author)
-
Body mass changes in a biparental incubator: the Redshank Tringa totanus
- 2010
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 2193-7206 .- 2193-7192. ; 151:1, s. 179-184
-
Journal article (peer-reviewed)abstract
- Incubation is a period of high energetic costs and accordingly body mass losses are often detected. Why birds lose body mass during incubation is not well understood; suggestions are that it is either a consequence of energetic constraints or adaptations to an optimal mass trajectory. We studied body mass changes through the incubation period in the Common Redshank Tringa totanus, a biparental incubator, on southern Gotland in the Baltic Sea. In contrast to what has been found in other biparental incubators, body mass of both sexes decreased linearly through the incubation period. The estimated mean body mass loss was 6.7 g (SE 1.7), corresponding to ca. 5% of initial body mass at incubation start. Hatching success in males was not related to body mass and size. In contrast, reproductive success, measured as successful production of fledged juveniles, in males was negatively related to body mass during incubation and positively related to body size. This finding supports the theory that body mass loss might follow an optimal mass trajectory, possibly to increase agility through the chick-rearing stage. However, energy constraints causing body mass loss cannot be ruled out; in fact, it is not unlikely that body mass may change due to a combination of both adaptation and stress.
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| 48. |
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| 49. |
- Pechacek, Peter, et al.
(author)
-
Classical polyandry found in the three-toed woodpecker Picoides tridactylus
- 2006
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206. ; 147:1, s. 112-114
-
Journal article (peer-reviewed)abstract
- We report two cases of simultaneous, social polyandry in the three-toed woodpecker Picoides tridactylus found in Berchtesgaden National Park, Germany during an 11-year study. The first case was between two neighbouring pairs in 2003. A female incubated both of her clutches during a period of at least 8 days. The second case was in 2004 between a widowed male and a female of a neighbouring pair. This time, a female divided parental care between her two clutches during a period of at least 27 days. We hypothesise that social polyandry in the three-toed woodpecker may be linked to the parental quality of the first male.
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| 50. |
- Sadanandan, K. R., et al.
(author)
-
Genetic and biometric variation across the fragmented range of Jerdon's Babbler, Chrysomma altirostre, a threatened Oriental grassland specialist
- 2018
-
In: Journal of Ornithology. - : Springer Science and Business Media LLC. - 0021-8375 .- 2193-7192 .- 2193-7206. ; 159:2, s. 575-579
-
Journal article (peer-reviewed)abstract
- Jerdon's Babbler Chrysomma altirostre is a threatened Oriental grassland specialist passerine heavily affected by habitat loss. Its now-relictual range spans from Pakistan to Myanmar covering three poorly-studied subspecies. Our study of subspecific differentiation revealed limited range-wide mitochondrial divergences, suggesting that mountain ranges and other geographic barriers may not have been insurmountable obstacles to inter-subspecific Pleistocene connectivity of this highly specialized grassland bird. For the westernmost subspecies scindicum, we report on phenotypic differentiation consistent with Gloger's Rule, and ecomorphological adaptations to arid environments requiring increased mobility.
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