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Barn Swallows (barn + swallow)
Selected AbstractsExperimental tail shortening in Barn Swallows (Hirundo rustica) affects haematocritFUNCTIONAL ECOLOGY, Issue 5 2005J. J. CUERVO Summary 1Recent studies in Scotland suggest that the outermost tail feathers of Barn Swallows (Hirundo rustica Linnaeus) may be around 10,12 mm longer than the aerodynamic optimum, with sexual selection for long tails accounting for this extra length. 2To test this hypothesis, we shortened the outermost tail feathers in male and female Barn Swallows in southern Spain by cutting 1, 11 or 21 mm from the tips of the feathers, and checked for change in haematocrit 1 month later. Haematocrit levels were high when birds arrived at the breeding grounds due to an intense effort for flight during migration, but these levels decreased during the breeding season. We predicted that this decrease would be more pronounced when tail length was closer to the aerodynamic optimum (tails shortened by 11 mm), and less pronounced as tail length was displaced from that optimum (tails shortened by 1 or 21 mm). 3Contrary to expectations, we found that the smaller the experimental reduction in tail length, the more pronounced the decrease in haematocrit. Barn Swallows with little parental effort and originally long tail feathers experienced a more pronounced decrease in haematocrit than individuals with strong parental effort and originally short tail feathers, respectively, although only in the group of birds with tails shortened by 21 mm. 4These results do not support the hypothesis that outermost tail feathers in Barn Swallows have been elongated because of sexual selection, at least in the population studied, but are consistent with tail length being at an aerodynamic optimum, or very close to it. Differences in tail length among populations might help to understand the disagreement with previous studies. [source] Barn Swallows Hirundo rustica disperse seeds of Rooikrans Acacia cyclops, an invasive alien plant in the Fynbos BiomeIBIS, Issue 3 2007LES G. UNDERHILL Rooikrans Acacia cyclops is an invasive plant species in the coastal region of South Africa, especially the Fynbos Biome. It is endemic to southwestern Australia. Seeds are bird-dispersed, mostly by frugivores and granivores. We report that at one locality in South Africa, Barn Swallows Hirundo rustica, normally regarded as obligate foragers of aerial arthropods, also consumed the seeds and associated arils of Rooikrans shrubs and trees. The seeds were voided and the arils digested. Three thousand Barn Swallows in the region where this was observed conceivably consumed and voided two million Rooikrans seeds during the 5-month non-breeding period. Barn Swallows are therefore dispersers of Rooikrans seeds. Many of the bird species known to consume Rooikrans seeds are territorial, so that seeds are not dispersed far beyond existing acacia stands. Barn Swallows cover large distances between feeding areas and roosts, and could therefore disperse seeds far from existing stands. This development adds urgency to the need to eradicate Rooikrans from the Fynbos Biome. [source] Different roles of natural and sexual selection on senescence of plumage colour in the barn swallowFUNCTIONAL ECOLOGY, Issue 2 2009Ismael Galván Summary 1Colour may show effects of senescence because the pigment or structures involved in production of colouration deteriorate with age. 2We tested this hypothesis by investigating age-related changes in plumage colour for two feather tracts coloured by eumelanin or pheomelanin in a longitudinal study of a cohort of barn swallows Hirundo rustica that reached very old age (at least 5 years). 3The level of melanization of the throat increased with age in both sexes, but particularly in females. In contrast, the black colour of the plumage of the back was unrelated to age in both sexes. 4These age-dependent patterns of colouration of different feather tracts of male and female barn swallows suggest that effects of senescence are trait-specific depending on their importance in sexual signalling. The red throat colour based on pheomelanin is involved in sexual selection, with a strong effect in males, but not in females. In contrast, the black colour of the back based on eumelanin is unrelated to sexual selection, but is under natural selection due to intense abrasion of this feather tract. 5These findings suggest that the relative importance of natural and sexual selection are important determinants of the pattern and rate of senescence of colour. [source] Host,parasite interactions and vectors in the barn swallow in relation to climate changeGLOBAL CHANGE BIOLOGY, Issue 4 2010A. P. MØLLER Abstract Recent climate change has affected the phenology of numerous species, and such differential changes may affect host,parasite interactions. Using information on vectors (louseflies, mosquitoes, blackflies) and parasites (tropical fowl mite Ornithonyssus bursa, the lousefly Ornithomyia avicularia, a chewing louse Brueelia sp., two species of feather mites Trouessartia crucifera and Trouessartia appendiculata, and two species of blood parasites Leucozytozoon whitworthi and Haemoproteus prognei) of the barn swallow Hirundo rustica collected during 1971,2008, I analyzed temporal changes in emergence and abundance, relationships with climatic conditions, and changes in the fitness impact of parasites on their hosts. Temperature and rainfall during the summer breeding season of the host increased during the study. The intensity of infestation by mites decreased, but increased for the lousefly during 1982,2008. The prevalence of two species of blood parasites increased during 1988,2008. The timing of first mass emergence of mosquitoes and blackflies advanced. These temporal changes in phenology and abundance of parasites and vectors could be linked to changes in temperature, but less so to changes in precipitation. Parasites had fitness consequences for hosts because intensity of the mite and the chewing louse was significantly associated with delayed breeding of the host, while a greater abundance of feather mites was associated with earlier breeding. Reproductive success of the host decreased with increasing abundance of the chewing louse. The temporal decrease in mite abundance was associated with advanced breeding of the host, while the increase in abundance of the lousefly was associated with earlier breeding. Virulence by the tropical fowl mite decreased with increasing temperature, independent of confounding factors. These findings suggest that climate change affects parasite species differently, hence altering the composition of the parasite community, and that climate change causes changes in the virulence of parasites. Because the changing phenology of different species of parasites had both positive and negative effects on their hosts, and because the abundance of some parasites increased, while that of other decreased, there was no consistent temporal change in host fitness during 1971,2008. [source] Condition, reproduction and survival of barn swallows from ChernobylJOURNAL OF ANIMAL ECOLOGY, Issue 6 2005A. P. MØLLER Summary 1We investigated the relationship between radiation arising from the fall-out due to the explosion of the nuclear reactor at Chernobyl, Ukraine, and body condition, rate of reproduction and survival in a migratory passerine bird, the barn swallow Hirundo rustica L., by comparing a contaminated region and a control region (Kanev) during 6 years between 1991 and 2004. 2The fraction of nonreproducing adults was on average 23% in Chernobyl compared with close to zero in Kanev and other European populations. 3Body condition as estimated from body mass was similar in Chernobyl and Kanev. Although laying date did not differ significantly between the two regions, clutch was reduced by 7%, brood size by 14% and hatching success by 5% in the Chernobyl region relative to the control area. 4Annual adult survival, estimated from mark,recapture analyses, was on average 28% in the Chernobyl region, but 40% in Kanev. 5The relationships were generally confirmed in rank correlation analyses between response variables and ambient radiation levels in different colonies. 6The overall findings are consistent with the hypothesis that radioactive contamination in the Chernobyl region has significant negative impact on rates of reproduction and survival of the barn swallow. We hypothesize that these effects are mediated by antioxidants and/or mutations. [source] Different roles of natural and sexual selection on senescence of plumage colour in the barn swallowFUNCTIONAL ECOLOGY, Issue 2 2009Ismael Galván Summary 1Colour may show effects of senescence because the pigment or structures involved in production of colouration deteriorate with age. 2We tested this hypothesis by investigating age-related changes in plumage colour for two feather tracts coloured by eumelanin or pheomelanin in a longitudinal study of a cohort of barn swallows Hirundo rustica that reached very old age (at least 5 years). 3The level of melanization of the throat increased with age in both sexes, but particularly in females. In contrast, the black colour of the plumage of the back was unrelated to age in both sexes. 4These age-dependent patterns of colouration of different feather tracts of male and female barn swallows suggest that effects of senescence are trait-specific depending on their importance in sexual signalling. The red throat colour based on pheomelanin is involved in sexual selection, with a strong effect in males, but not in females. In contrast, the black colour of the back based on eumelanin is unrelated to sexual selection, but is under natural selection due to intense abrasion of this feather tract. 5These findings suggest that the relative importance of natural and sexual selection are important determinants of the pattern and rate of senescence of colour. [source] Effect of current reproduction on apparent survival, breeding dispersal, and future reproduction in barn swallows assessed by multistate capture,recapture modelsJOURNAL OF ANIMAL ECOLOGY, Issue 3 2009Michael Schaub Summary 1Theoretical models predict a negative effect of current reproduction on breeding dispersal, survival and future reproduction, and many studies confirm these predictions. Yet, results of most previous studies may be difficult to interpret because the fate of the affected individuals cannot always be observed. Detection is almost always imperfect and some individuals emigrate from the study area, resulting in biased estimates of both survival and dispersal. 2Most studies bypass these problems with strong assumptions. We use a multistate capture,recapture model that does not require these assumptions. States are defined based on classes of reproductive success and on observed dispersal events within the study area. By accounting for imperfect detection within the study area, the model allows estimation of the effect of reproductive success on apparent survival, dispersal probabilities within the study area and the annual transition probabilities among classes of reproductive success. Based on an assumption about the estimate of real survival, the model allows the estimation of total dispersal that is not specific to a fixed study area. 3We applied this model to capture,recapture data of 2262 adult barn swallows (Hirundo rustica) sampled from 1997,2004 in eight local populations in Switzerland. 4We found that dispersal within the study area decreased with increasing reproductive success in both sexes, that reproductive success was not affected by preceding dispersal and that apparent survival of females but not of males increased with increasing reproductive success. Apparent survival of females with high reproductive success was identical to apparent survival of males suggesting that this estimate of apparent survival (0·48) was close to true survival. Total breeding dispersal was generally higher in females and it increased with decreasing reproductive success in both sexes. Current reproductive success depended on reproductive success in the preceding year suggesting that individual differences were of importance. 5Our study highlights that reproductive success was an important factor affecting breeding dispersal and population turnover. While unsuccessful males mainly remained in the local populations, many unsuccessful females left them. Population turnover of adult swallows was mainly due to unsuccessful females. [source] Condition, reproduction and survival of barn swallows from ChernobylJOURNAL OF ANIMAL ECOLOGY, Issue 6 2005A. P. MØLLER Summary 1We investigated the relationship between radiation arising from the fall-out due to the explosion of the nuclear reactor at Chernobyl, Ukraine, and body condition, rate of reproduction and survival in a migratory passerine bird, the barn swallow Hirundo rustica L., by comparing a contaminated region and a control region (Kanev) during 6 years between 1991 and 2004. 2The fraction of nonreproducing adults was on average 23% in Chernobyl compared with close to zero in Kanev and other European populations. 3Body condition as estimated from body mass was similar in Chernobyl and Kanev. Although laying date did not differ significantly between the two regions, clutch was reduced by 7%, brood size by 14% and hatching success by 5% in the Chernobyl region relative to the control area. 4Annual adult survival, estimated from mark,recapture analyses, was on average 28% in the Chernobyl region, but 40% in Kanev. 5The relationships were generally confirmed in rank correlation analyses between response variables and ambient radiation levels in different colonies. 6The overall findings are consistent with the hypothesis that radioactive contamination in the Chernobyl region has significant negative impact on rates of reproduction and survival of the barn swallow. We hypothesize that these effects are mediated by antioxidants and/or mutations. [source] Genetic and environmental effects on morphology and fluctuating asymmetry in nestling barn swallowsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2000Cadée A barn swallow Hirundo rustica partial cross-fostering experiment with simultaneous brood size manipulation was conducted in two years with contrasting weather conditions, to estimate heritable variation in tarsus, tail and wing size and fluctuating asymmetry. Environmental stress had contrasting effects depending on trait type. Significant heritabilities for tarsus, tail and wing size were found only in enlarged broods irrespective of year effects, while tarsus asymmetry was significantly heritable in the year with benign weather conditions irrespective of brood size manipulation effects. Tail, wing and composite (multicharacter) asymmetry were never significantly heritable. The environment with the higher heritability generally had higher additive genetic variance and lower environmental variance, irrespective of trait type. Heritability was larger for trait size than for trait asymmetry. Patterns of genetic variation in nestlings do not necessarily translate to the juvenile or adult stage, as indicated by lack of correlation between nestling and fledgling traits. [source] | ||||||||||