Tibor Szép - Academia.edu (original) (raw)

Papers by Tibor Szép

Research paper thumbnail of Telelő, vonuló és fészkelő területek időjárási és élőhelyi jellemzőinek szezonon belüli és közötti hatásai egy vonuló madárfaj állományára = Within and between seasonal influence of weather and habitat of the wintering, migration and breeding areas on the population of a migratory species

Research paper thumbnail of Investigation of the flexibility of bird feathers

Biomechanica Hungarica, Jun 1, 2014

A cikk bevezetője áttekinti azokat a szempontokat, amelyeket a biológus kutatók fogalmaznak meg a... more A cikk bevezetője áttekinti azokat a szempontokat, amelyeket a biológus kutatók fogalmaznak meg a madártollak hajlékonysági tulajdonságai vizsgálatára vonatkozóan. Ebből következik a kutatás célja: számszerűen meghatározni a partifecskék szélső faroktollának hajlékonysági tulajdonságait. A kísérleti programban 360 darab partifecske szélső faroktoll vizsgálatát végezték el a szerzők. A cikkben bemutatják a kétpontos hajlítóvizsgálat műszaki vonatkozásait, nevezetesen a vizsgálati feltételeket és az eredményeinek feldolgozására alkalmazható módszereket. Az erőlehajlás diagramok felvételére, azok elemzésére és a tollak hajlékonyságának jellemzésére olyan módszereket ismertetnek, amelyek a szakirodalomban jelenleg alkalmazott módszernél érzékenyebben tárják fel az egyes tollak hajlékonyságában mutatkozó különbségeket.

Research paper thumbnail of Identification of novel microsatellite loci in the sand martin, Riparia riparia, and cross-amplification of loci from other bird species

Journal of ornithology, Mar 7, 2010

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Exposure to ectoparasites increases within-brood variability in size and body mass in the sand martin

Oecologia, Oct 1, 2000

Parasites often have detrimental effects on their hosts, and only host individuals able to cope w... more Parasites often have detrimental effects on their hosts, and only host individuals able to cope with parasitism are likely to display induced or genetic resistance. Hosts may respond to parasitism by differential investment in offspring depending on their ability to cope with parasitism, because offspring that perform better than their siblings are themselves likely to have superior induced or genetic resistance. We tested whether nestlings of the highly colonial sand martin Riparia riparia were affected by the haematophagous tick Ixodes lividus by experimentally manipulating parasite loads of nests [nests sprayed with pyrethrum to remove parasites (sprayed), or nests sprayed with water (control)] at three stages of the breeding season. Prevalence and intensity of ticks were significantly affected by treatments. Breeding success was not significantly affected by treatment, although post-fledging survival was twice as high among nestlings from sprayed nests than from controls. Mean phenotypic traits of nestlings generally did not differ significantly among treatments, while within-brood variance in keel length (a skeletal character) and body mass were higher in control treatment broods than sprayed ones. Sedimentation rate, which reflects blood protein and immunoglobulin content, was significantly higher and less variable in sprayed than control broods. These findings are consistent with the suggestion that parasitism effects on host reproductive success act through an increase in the variance of offspring quality.

Research paper thumbnail of Mixed species flocking of tits (Parus spp.): a field experiment

Oecologia, Mar 1, 1989

Summary. We tested two general models of flocking behaviour, namely the antipredation model and f... more Summary. We tested two general models of flocking behaviour, namely the antipredation model and foraging efficiency model on mixed-species tit flocks (Parus spp.). After food addition the size of mixed-species flocks was significantly less than in the control samples. In the presence of extra food significantly more birds were observed either in monospecific flocks or solitary, than during the control observations. In the presence of a living predator the birds foraged in larger mixed-specifies flocks than during the control observations. In addition, the social behaviour of Great Spotted Woodpecker, Middle Spotted Woodpecker and Nuthatch shifted to mixed-specific flocking. The size of monospecific flocks was independent of both treatments. The density of birds increased significantly after food addition, while in the predator presence the birds tended to leave the forest. These results support the view that both the antipredation model and foraging efficiency model seem to be valid for mixed-species flocking. However, in the case of monospecific flocks, the territory maintenance could be the most important factor.

Research paper thumbnail of The status of the Hoopoe (Upupa epops) in Hungary: a review

Ornis Hungarica, Dec 1, 2015

The Hoopoe is a widespread species in Hungary with the strongest populations on the Great plains.... more The Hoopoe is a widespread species in Hungary with the strongest populations on the Great plains. The fact that in 2015 it became ‛The Bird of the Year' in Hungary offers the possibility to summarise the information about the distribution, population size, dispersion, migration as well as the nature conservation status of the Hoopoe population breeding in Hungary. In the period of 1999-2014 the number of breeding pairs and trend of population level was estimated based on the Common Bird Census database. The population size was estimated as 13,500-17,500 pairs with a stable trend (slope=-1.3%, SE=2.5%) over 1999-2014. There is very limited information on migration from bird ringing, only 8 recoveries between 1928-1963 indicate, that the Hungarian population is migrating on a south-southeast direction in autumn, wintering in the eastern parts of the Sahel, possibly in Chad and Sudan and migrates back in spring following a loop migration pattern further to the east. The main conservation issues are agricultural intensification impacting feeding possibilities, lack of nesting cavities and hunting during migration.

Research paper thumbnail of Mezőgazdasági területek felszínborításának és tájszerkezetének hatása három madárfaj gyakoriságára

Journal of Landscape Ecology, Jul 18, 2007

Research paper thumbnail of Age-independent telomere length predicts fitness in two bird Species

Molecular Ecology, Feb 16, 2006

Telomeres are dynamic DNA-protein structures that form protective caps at the ends of eukaryotic ... more Telomeres are dynamic DNA-protein structures that form protective caps at the ends of eukaryotic chromosomes. Although initial telomere length is partly genetically determined, subsequent accelerated telomere shortening has been linked to elevated levels of oxidative stress. Recent studies show that short telomere length alone is insufficient to induce cellular senescence; advanced attrition of these repetitive DNA sequences does, however, reflect ageing processes. Furthermore, telomeres vary widely in length between individuals of the same age, suggesting that individuals differ in their exposure or response to telomere-shortening stress factors. Here, we show that residual telomere length predicts fitness components in two phylogenetically distant bird species: longevity in sand martins, Riparia riparia , and lifetime reproductive success in dunlins, Calidris alpina. Our results therefore imply that individuals with longer than expected telomeres for their age are of higher quality.

Research paper thumbnail of Lokális, regionális és globális környezeti faktorok hatásai vonuló madarakra = Effects of local, regional and global environmental factors on migrating birds

Research paper thumbnail of Integrated population monitoring of sand martin Riparia riparia - an opportunity to monitor the effects of environmental disasters along the river Tisza

Research paper thumbnail of Discovering the migration and non-breeding areas of sand martins and house martins breeding in the Pannonian basin (central-eastern Europe)

Journal of Avian Biology, 2017

Research paper thumbnail of The role of information transfer under different food patterns: a simulation study

Research paper thumbnail of Population trends of common breeding and wintering birds in Hungary, decline of longdistance migrant and farmland birds during 1999–2012

Ornis Hungarica, Dec 1, 2012

Research paper thumbnail of Rapid evolutionary change in a secondary sexual character linked to climatic change

Journal of Evolutionary Biology, Oct 12, 2004

Research paper thumbnail of Aerial Hunting Techniques and Predation Success of HobbiesFalco subbuteoon Sand MartinRiparia ripariaat Breeding Colonies

Ardea, Apr 1, 2011

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Research paper thumbnail of Breeding dispersal patterns within a large Sand Martin (Riparia riparia) colony

Journal of ornithology, Sep 1, 2009

Research paper thumbnail of No evidence of genetic benefits from extra-pair fertilisations in female sand martins (Riparia riparia)

Journal of ornithology, Dec 13, 2006

Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pa... more Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pair paternity. Variation in extra-pair paternity among individuals may depend on how different individuals benefit from extra-pair fertilisations and on the opportunity to pursue extra-pair copulations. A long-term study of sand martins (Riparia riparia) in Hungary allowed us to examine patterns of extra-pair fertilisations in a large colony

Research paper thumbnail of Comparison of trace element and stable isotope approaches to the study of migratory connectivity: an example using two hirundine species breeding in Europe and wintering in Africa

Journal of ornithology, Feb 13, 2009

Analyses of stable isotopes and trace elements in feathers may provide important information abou... more Analyses of stable isotopes and trace elements in feathers may provide important information about location and habitat use during molt, thereby enabling the investigation of migratory connectivity and its ecological consequences in bird species that breed and winter in different areas. We have compared the conclusions arrived at based on the use of these two methods on the same samples

Research paper thumbnail of Habitat preference, escape behavior, and cues used by feather mites to avoid molting wing feathers

Behavioral Ecology, Dec 15, 2005

We analyzed the pattern of distribution and the effect of molting on the escape behavior of feath... more We analyzed the pattern of distribution and the effect of molting on the escape behavior of feather mites on the wing feathers during the nonmolting and molting season of the barn swallow Hirundo rustica. Feather mites showed consistent preference for the second outermost primary, with a steady decrease in proximal distance and avoidance of the outermost primary. Several explanations are suggested to explain this unusual distribution. Further, analyzing the escape behavior of feather mites on molting primaries, we show that mites avoid the feathers destined to be dropped next on molting barn swallows, and in the case of the outermost primary, mites use the ''last moment'' strategy, namely, leaving feathers shortly before it is dropped. Next, we performed an experiment in which we simulated shedding feathers or feathers about to be shed on nonmolting barn swallows, in order to test cues used by feather mites in avoiding molting primaries. Both the vibration of the incised feather and the gap of the pulled feather induced mites to leave primaries situated distally, at two-feathers distance from the manipulated primary, related to the control group. Our results show that feather mites have the ability to perceive the signal produced by the feather that will drop next and by the gap of the missing feather. It remains to be demonstrated, whether feather mites have the ability to perceive the vibration of the feather per se or they perceive the altered airflow caused by the vibrating feathers.

Research paper thumbnail of Use of trace elements in feathers of sand martin <i>Riparia riparia</i> for identifying moulting areas

Journal of Avian Biology, Aug 28, 2003

We investigated whether trace elements in tail feathers of an insectivorous and long-distance mig... more We investigated whether trace elements in tail feathers of an insectivorous and long-distance migratory bird species could be used to identify moulting areas and hence migratory pathways. We analysed tail feathers from birds of different age and sex collected from a range of different breeding sites across Europe. The site of moult had a large effect on elemental composition of feathers of birds, both at the European and African moulting sites. Analysis of feathers of nestlings with known origin suggested that the elemental composition of feathers depended largely upon the micro-geographical location of the colony. The distance between moulting areas could not explain the level of differences in trace elements. Analysis of feathers grown by the same individuals on the African wintering grounds and in the following breeding season in Europe showed a large difference in composition indicating that moulting site affects elemental composition. Tail feathers moulted in winter in Africa by adults breeding in different European regions differed markedly in elemental composition, indicating that they used different moulting areas. Analysis of tail feathers of the same adult individuals in two consecutive years showed that sand martins in their first and second wintering season grew feathers with largely similar elemental composition, although the amounts of several elements in tail feathers of the older birds was lower. There was no difference between the sexes in the elemental composition of their feathers grown in Africa. Investigation of the trace element composition of feathers could be a useful method for studying similarity among groups of individuals in their use of moulting areas.

Research paper thumbnail of Telelő, vonuló és fészkelő területek időjárási és élőhelyi jellemzőinek szezonon belüli és közötti hatásai egy vonuló madárfaj állományára = Within and between seasonal influence of weather and habitat of the wintering, migration and breeding areas on the population of a migratory species

Research paper thumbnail of Investigation of the flexibility of bird feathers

Biomechanica Hungarica, Jun 1, 2014

A cikk bevezetője áttekinti azokat a szempontokat, amelyeket a biológus kutatók fogalmaznak meg a... more A cikk bevezetője áttekinti azokat a szempontokat, amelyeket a biológus kutatók fogalmaznak meg a madártollak hajlékonysági tulajdonságai vizsgálatára vonatkozóan. Ebből következik a kutatás célja: számszerűen meghatározni a partifecskék szélső faroktollának hajlékonysági tulajdonságait. A kísérleti programban 360 darab partifecske szélső faroktoll vizsgálatát végezték el a szerzők. A cikkben bemutatják a kétpontos hajlítóvizsgálat műszaki vonatkozásait, nevezetesen a vizsgálati feltételeket és az eredményeinek feldolgozására alkalmazható módszereket. Az erőlehajlás diagramok felvételére, azok elemzésére és a tollak hajlékonyságának jellemzésére olyan módszereket ismertetnek, amelyek a szakirodalomban jelenleg alkalmazott módszernél érzékenyebben tárják fel az egyes tollak hajlékonyságában mutatkozó különbségeket.

Research paper thumbnail of Identification of novel microsatellite loci in the sand martin, Riparia riparia, and cross-amplification of loci from other bird species

Journal of ornithology, Mar 7, 2010

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Research paper thumbnail of Exposure to ectoparasites increases within-brood variability in size and body mass in the sand martin

Oecologia, Oct 1, 2000

Parasites often have detrimental effects on their hosts, and only host individuals able to cope w... more Parasites often have detrimental effects on their hosts, and only host individuals able to cope with parasitism are likely to display induced or genetic resistance. Hosts may respond to parasitism by differential investment in offspring depending on their ability to cope with parasitism, because offspring that perform better than their siblings are themselves likely to have superior induced or genetic resistance. We tested whether nestlings of the highly colonial sand martin Riparia riparia were affected by the haematophagous tick Ixodes lividus by experimentally manipulating parasite loads of nests [nests sprayed with pyrethrum to remove parasites (sprayed), or nests sprayed with water (control)] at three stages of the breeding season. Prevalence and intensity of ticks were significantly affected by treatments. Breeding success was not significantly affected by treatment, although post-fledging survival was twice as high among nestlings from sprayed nests than from controls. Mean phenotypic traits of nestlings generally did not differ significantly among treatments, while within-brood variance in keel length (a skeletal character) and body mass were higher in control treatment broods than sprayed ones. Sedimentation rate, which reflects blood protein and immunoglobulin content, was significantly higher and less variable in sprayed than control broods. These findings are consistent with the suggestion that parasitism effects on host reproductive success act through an increase in the variance of offspring quality.

Research paper thumbnail of Mixed species flocking of tits (Parus spp.): a field experiment

Oecologia, Mar 1, 1989

Summary. We tested two general models of flocking behaviour, namely the antipredation model and f... more Summary. We tested two general models of flocking behaviour, namely the antipredation model and foraging efficiency model on mixed-species tit flocks (Parus spp.). After food addition the size of mixed-species flocks was significantly less than in the control samples. In the presence of extra food significantly more birds were observed either in monospecific flocks or solitary, than during the control observations. In the presence of a living predator the birds foraged in larger mixed-specifies flocks than during the control observations. In addition, the social behaviour of Great Spotted Woodpecker, Middle Spotted Woodpecker and Nuthatch shifted to mixed-specific flocking. The size of monospecific flocks was independent of both treatments. The density of birds increased significantly after food addition, while in the predator presence the birds tended to leave the forest. These results support the view that both the antipredation model and foraging efficiency model seem to be valid for mixed-species flocking. However, in the case of monospecific flocks, the territory maintenance could be the most important factor.

Research paper thumbnail of The status of the Hoopoe (Upupa epops) in Hungary: a review

Ornis Hungarica, Dec 1, 2015

The Hoopoe is a widespread species in Hungary with the strongest populations on the Great plains.... more The Hoopoe is a widespread species in Hungary with the strongest populations on the Great plains. The fact that in 2015 it became ‛The Bird of the Year' in Hungary offers the possibility to summarise the information about the distribution, population size, dispersion, migration as well as the nature conservation status of the Hoopoe population breeding in Hungary. In the period of 1999-2014 the number of breeding pairs and trend of population level was estimated based on the Common Bird Census database. The population size was estimated as 13,500-17,500 pairs with a stable trend (slope=-1.3%, SE=2.5%) over 1999-2014. There is very limited information on migration from bird ringing, only 8 recoveries between 1928-1963 indicate, that the Hungarian population is migrating on a south-southeast direction in autumn, wintering in the eastern parts of the Sahel, possibly in Chad and Sudan and migrates back in spring following a loop migration pattern further to the east. The main conservation issues are agricultural intensification impacting feeding possibilities, lack of nesting cavities and hunting during migration.

Research paper thumbnail of Mezőgazdasági területek felszínborításának és tájszerkezetének hatása három madárfaj gyakoriságára

Journal of Landscape Ecology, Jul 18, 2007

Research paper thumbnail of Age-independent telomere length predicts fitness in two bird Species

Molecular Ecology, Feb 16, 2006

Telomeres are dynamic DNA-protein structures that form protective caps at the ends of eukaryotic ... more Telomeres are dynamic DNA-protein structures that form protective caps at the ends of eukaryotic chromosomes. Although initial telomere length is partly genetically determined, subsequent accelerated telomere shortening has been linked to elevated levels of oxidative stress. Recent studies show that short telomere length alone is insufficient to induce cellular senescence; advanced attrition of these repetitive DNA sequences does, however, reflect ageing processes. Furthermore, telomeres vary widely in length between individuals of the same age, suggesting that individuals differ in their exposure or response to telomere-shortening stress factors. Here, we show that residual telomere length predicts fitness components in two phylogenetically distant bird species: longevity in sand martins, Riparia riparia , and lifetime reproductive success in dunlins, Calidris alpina. Our results therefore imply that individuals with longer than expected telomeres for their age are of higher quality.

Research paper thumbnail of Lokális, regionális és globális környezeti faktorok hatásai vonuló madarakra = Effects of local, regional and global environmental factors on migrating birds

Research paper thumbnail of Integrated population monitoring of sand martin Riparia riparia - an opportunity to monitor the effects of environmental disasters along the river Tisza

Research paper thumbnail of Discovering the migration and non-breeding areas of sand martins and house martins breeding in the Pannonian basin (central-eastern Europe)

Journal of Avian Biology, 2017

Research paper thumbnail of The role of information transfer under different food patterns: a simulation study

Research paper thumbnail of Population trends of common breeding and wintering birds in Hungary, decline of longdistance migrant and farmland birds during 1999–2012

Ornis Hungarica, Dec 1, 2012

Research paper thumbnail of Rapid evolutionary change in a secondary sexual character linked to climatic change

Journal of Evolutionary Biology, Oct 12, 2004

Research paper thumbnail of Aerial Hunting Techniques and Predation Success of HobbiesFalco subbuteoon Sand MartinRiparia ripariaat Breeding Colonies

Ardea, Apr 1, 2011

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access t... more BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Research paper thumbnail of Breeding dispersal patterns within a large Sand Martin (Riparia riparia) colony

Journal of ornithology, Sep 1, 2009

Research paper thumbnail of No evidence of genetic benefits from extra-pair fertilisations in female sand martins (Riparia riparia)

Journal of ornithology, Dec 13, 2006

Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pa... more Genetic parentage studies of socially monogamous birds reveal a widespread prevalence of extra-pair paternity. Variation in extra-pair paternity among individuals may depend on how different individuals benefit from extra-pair fertilisations and on the opportunity to pursue extra-pair copulations. A long-term study of sand martins (Riparia riparia) in Hungary allowed us to examine patterns of extra-pair fertilisations in a large colony

Research paper thumbnail of Comparison of trace element and stable isotope approaches to the study of migratory connectivity: an example using two hirundine species breeding in Europe and wintering in Africa

Journal of ornithology, Feb 13, 2009

Analyses of stable isotopes and trace elements in feathers may provide important information abou... more Analyses of stable isotopes and trace elements in feathers may provide important information about location and habitat use during molt, thereby enabling the investigation of migratory connectivity and its ecological consequences in bird species that breed and winter in different areas. We have compared the conclusions arrived at based on the use of these two methods on the same samples

Research paper thumbnail of Habitat preference, escape behavior, and cues used by feather mites to avoid molting wing feathers

Behavioral Ecology, Dec 15, 2005

We analyzed the pattern of distribution and the effect of molting on the escape behavior of feath... more We analyzed the pattern of distribution and the effect of molting on the escape behavior of feather mites on the wing feathers during the nonmolting and molting season of the barn swallow Hirundo rustica. Feather mites showed consistent preference for the second outermost primary, with a steady decrease in proximal distance and avoidance of the outermost primary. Several explanations are suggested to explain this unusual distribution. Further, analyzing the escape behavior of feather mites on molting primaries, we show that mites avoid the feathers destined to be dropped next on molting barn swallows, and in the case of the outermost primary, mites use the ''last moment'' strategy, namely, leaving feathers shortly before it is dropped. Next, we performed an experiment in which we simulated shedding feathers or feathers about to be shed on nonmolting barn swallows, in order to test cues used by feather mites in avoiding molting primaries. Both the vibration of the incised feather and the gap of the pulled feather induced mites to leave primaries situated distally, at two-feathers distance from the manipulated primary, related to the control group. Our results show that feather mites have the ability to perceive the signal produced by the feather that will drop next and by the gap of the missing feather. It remains to be demonstrated, whether feather mites have the ability to perceive the vibration of the feather per se or they perceive the altered airflow caused by the vibrating feathers.

Research paper thumbnail of Use of trace elements in feathers of sand martin <i>Riparia riparia</i> for identifying moulting areas

Journal of Avian Biology, Aug 28, 2003

We investigated whether trace elements in tail feathers of an insectivorous and long-distance mig... more We investigated whether trace elements in tail feathers of an insectivorous and long-distance migratory bird species could be used to identify moulting areas and hence migratory pathways. We analysed tail feathers from birds of different age and sex collected from a range of different breeding sites across Europe. The site of moult had a large effect on elemental composition of feathers of birds, both at the European and African moulting sites. Analysis of feathers of nestlings with known origin suggested that the elemental composition of feathers depended largely upon the micro-geographical location of the colony. The distance between moulting areas could not explain the level of differences in trace elements. Analysis of feathers grown by the same individuals on the African wintering grounds and in the following breeding season in Europe showed a large difference in composition indicating that moulting site affects elemental composition. Tail feathers moulted in winter in Africa by adults breeding in different European regions differed markedly in elemental composition, indicating that they used different moulting areas. Analysis of tail feathers of the same adult individuals in two consecutive years showed that sand martins in their first and second wintering season grew feathers with largely similar elemental composition, although the amounts of several elements in tail feathers of the older birds was lower. There was no difference between the sexes in the elemental composition of their feathers grown in Africa. Investigation of the trace element composition of feathers could be a useful method for studying similarity among groups of individuals in their use of moulting areas.