Search

Aerial insectivorous birds breeding in North America have experienced decades of population declines for reasons hypothesized to be related to changes in their insect prey. In agricultural landscapes, land management practices can affect insect communities, leading to concerns that ongoing trends toward more intensive cultivation could affect the ability of farmland-breeding aerial insectivores to forage and provision their offspring with aerial insect prey. To understand how differences in agricultural intensity may affect the foraging behavior of different aerial insectivore species, we used GPS tags to compare the movements and habitat use of 2 species with different foraging ecologies, Hirundo rustica (Barn Swallow) and Tachycineta bicolor (Tree Swallow), breeding at 17 sites in agricultural landscapes in Saskatchewan, Canada. Although we identified differences in foraging behavior consistent with each species' reported ecological traits, including T. bicolor foraging farther and over larger areas than H. rustica , overall foraging behavior was similar between species. Resource selection function analyses indicated that both species used wetlands disproportionately often relative to local wetland availability, especially when detected farther from their nests. Hirundo rustica and T. bicolor both also avoided cropped foraging habitat, using it proportionally less than it was locally available. In landscapes with greater wetland cover, both species selected for wetland habitat more strongly, and among T. bicolor , higher wetland density decreased maximum foraging distance and home range area. In contrast, we found no effect of crop cover on foraging habitat selection or foraging movements. These findings suggest that H. rustica and T. bicolor breeding in Saskatchewan agroecosystems share similar foraging strategies, with wetland habitats appearing to be highly important despite comprising only a small proportion of landscape area. Overall, these results indicate that protecting wetland habitats should be a priority for aerial insectivore conservation in the intensive agricultural landscapes such as the Canadian prairies. [ABSTRACT FROM AUTHOR]

Swallows (Hirundo spp.) inhabit a variety of habitats in both tropical and temperate zones. Barn Swallows (Hirundo rustica), in particular, frequently roost in large numbers and construct mud nests on buildings, causing nuisance to humans. At the Glami Lemi Biotechnology Research Centre (GLBRC), which is located in Peninsular Malaysia, there are certain structures that are frequently utilised by a large number of swallows for perching and resting. This results in the defacement of the exterior walls caused by their droppings. Hence, the analysis presented in this paper delves into the factors influencing their presence and numbers. The objective of this study was to examine the fluctuations in the number of perched Barn Swallows and their relationship with three environmental parameters: temperature, relative humidity, and light intensity. Three hours of observation were conducted in two different sessions (i.e., morning and afternoon) three times per week for one year. The results showed that the number of Barn Swallows perched appeared to be stable throughout the year, except for November and December, when it increased tremendously and reached its peak. A Spearman rank analysis was conducted to investigate the correlation between the number of swallows perched and the environmental parameters. The analysis was restricted to only periods when the birds were present. A significant effect of relative humidity and temperature was observed for the morning session, promoting the relationship between the environmental parameters and the perching/resting behaviour of this species. This situation is parallel with the afternoon session, where all three environmental parameters showed a significant effect on swallows’ numbers. This study not only provides valuable information to the GLBRC’s management to effectively anticipate appropriate steps to mitigate the influx of Barn Swallows but also enhances our knowledge of the perching/ resting behaviour of this species. [ABSTRACT FROM AUTHOR]

Copyright of Acta Zoologica Lilloana is the property of Fundacion Miguel Lillo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract, author, keywords, institution, and cited literature, and used CiteSpace (version 6.1.R3) to visualize the data through the knowledge map, burst keyword analysis, cluster analysis, and collaborative network analysis. Results: A total of 979 articles and reviews were retrieved. Regarding productivity, the top 2 countries were the United States (n =239) and Japan (n =236). Hidetaka Wakabayashi (n =26) was one of the most prolific writers. The first paper in the frequency ranking of references cited was a white paper: European Society for Swallowing Disorders and European Union Geriatric Medicine Society white paper: oropharyngeal dysphagia as a geriatric syndrome (n =53). "Prevalence" (n =173), "risk factor" (n =119), and "aspiration pneumonia" (n =108) were the most frequently occurring keywords (excluding defining nouns). The study identified reliability, tongue pressure, home discharge, and swallowing function as research hotspots from 2020 to 2022. Conclusion: Prevalence, risk factors, and pneumonia are significant areas of study. Tongue pressure and sarcopenia are research hotspots and potential targets. In the future, research on dysphagia needs to refine strategies for prevention and control, as well as provide tertiary preventative services. [ABSTRACT FROM AUTHOR]

The intestinal microbiota plays an important role in the digestion of food provided by parents to their hatchlings. Non-pathogenic bacteria in the digestive tract can be significantly beneficial to the host species, while pathogenic bacteria can reduce hatchling survival and lead to a decline in the number of new generation. Microbiological analysis of cloacal microflora of hatchlings revealed a highly diverse microbial load present from hatching until fledging (at 15 days) in Barn Swallow (Hirundo rustica). The intestinal microflora of 15-day-olds was the most diverse, and two groups are dependent on age: CPG and Lactobacilli are mostly present in hatchlings of the second and third ages (10 and 15 days). Our research was conducted to identify certain bacterial species, such as E. coli, Salmonella, Pseudomonas, Lactobacillus, Streptococcus, and Staphylococcus. The presence of most species was related to age, while the presence of Salmonella was accidental. [ABSTRACT FROM AUTHOR]

Insectivorous birds are key suppliers of crucial ecosystem services, especially important for pest control in agricultural systems, and are globally decreasing at a fast rate. Among them, the declining barn swallow Hirundo rustica is particularly linked to cattle farms, where it is impacted by changes in livestock husbandry practices.The presence of swallows in cattle sheds might contribute to control insect pests, but such an effect had never been explored. With this work, we evaluated the potential control effect exerted by barn swallow on economically relevant pest insects, filth flies.To assess whether swallows inside the cattle sheds influence the activity rate of pest flies (especially Musca domestica and Stomoxys calcitrans), we assessed the relative abundance of swallows and flies over 16 weeks in nine different cattle farms in Non valley (Trentino, North‐east Italy), either occupied or not by nesting swallows. From April 2022 to August 2022, we collected weekly data on the activity rate of flies by placing eight white spot cards inside each of nine cattle sheds and counting the deposition of faecal and regurgitation spots by flies. Simultaneously, we collected weekly data regarding swallow occurrence, brood size, number and age of chicks.We applied generalised linear mixed effect models on the activity rate of flies, with spot card and farm as nested random effects, to account for potential random variability between cards and farms. We then assessed through model selection the effect of number of cows, number of swallows, and temperature or week alternatively. Temperature and week were modelled also in interaction with the number of swallows.Fly activity rate followed a seasonal trend with a peak in July, which was markedly lower where swallows were present. Moreover, the positive relationship between flies and temperature was lessened when swallows were abundant.Synthesis and applications. Barn swallows are effective biological control agents for lowering pest fly activity in livestock farms. Farmers were actively involved in swallow conservation within their sheds, also with a shared memorandum‐of‐intent. Harnessing the ecosystem services supplied by farmland birds could bring positive outcomes for people and biodiversity. [ABSTRACT FROM AUTHOR]

The presence of feathers is a vital characteristic among birds, yet most modern birds had no feather on their feet. The discoveries of feathers on the hind limbs of basal birds and dinosaurs have sparked an interest in the evolutionary origin and genetic mechanism of feathered feet. However, the majority of studies investigating the genes associated with this trait focused on domestic populations. Understanding the genetic mechanism underpinned feathered-foot development in wild birds is still in its infancy. Here, we assembled a chromosome-level genome of the Asian house martin (Delichon dasypus) using the long-read High Fidelity sequencing approach to initiate the search for genes associated with its feathered feet. We employed the whole-genome alignment of D. dasypus with other swallow species to identify high-SNP regions and chromosomal inversions in the D. dasypus genome. After filtering out variations unrelated to D. dasypus evolution, we found six genes related to feather development near the high-SNP regions. We also detected three feather development genes in chromosomal inversions between the Asian house martin and the barn swallow genomes. We discussed their association with the wingless/integrated (WNT), bone morphogenetic protein, and fibroblast growth factor pathways and their potential roles in feathered-foot development. Future studies are encouraged to utilize the D. dasypus genome to explore the evolutionary process of the feathered-foot trait in avian species. This endeavor will shed light on the evolutionary path of feathers in birds. [ABSTRACT FROM AUTHOR]

Anthropogenic noise can affect a number of behavioral, physiological, and ecological aspects of animals from major taxonomic groups, raising serious conservation concerns. For example, noise pollution impacts communicative behavior and perception of signals, movements and distribution, as well as predator–prey interactions, such as hunting success or predator detection and predation risk assessment. We have carried out an experimental playback study, in which we investigated whether exposure to anthropogenic noise (sound of a tractor) distracts free-ranging barn swallows Hirundo rustica from paying attention to an approaching human "predator" (the "cognitive distraction" hypothesis), or whether noise leads to increased responsiveness to this "predator" (the "increased threat" hypothesis). The subjects were male barn swallows attending their breeding territories during the time when the females were incubating. We found that barn swallow males initiated flight at significantly greater distances to the approaching human "predator" in the noise treatment than during the quiet control trials. These results suggest that anthropogenic noise causes increased vigilance and reactivity rather than a distraction, enabling birds to avoid the "predator" more quickly. We further discuss the mechanism behind the increased alertness in response to noise and contrast the "increased threat" mechanism, usually tested in previous studies, with an alternative "cognitive sensitization" mechanism. [ABSTRACT FROM AUTHOR]

Conservation efforts are needed in the face of the rapid decline in farmland birds over the past decades. While existing conservation strategies have shown limited success, there is a growing recognition of the role of farmers as primary stakeholders in agroecosystems conservation. We applied the ''Human Dimension'' approach, which emphasizes the importance of human perspectives on wildlife conservation, to assess whether a long-term monitoring project of barn swallows Hirundo rustica, ongoing since 1999, has heightened farmers’ awareness regarding biodiversity protection. Indeed, while monitoring serves to track population trends and understand the factors influencing species dynamics, it also provides opportunities for interaction between researchers and farmers. Through in-person administration of the questionnaire, we investigated the impact of the barn swallow monitoring project on farmers’ environmental consciousness in terms of their perceptions of the environment, knowledge about priority habitats for biodiversity, and preferences for environmental awareness strategies. Subsequently, we investigated whether environmental consciousness and the participation in the barn swallow monitoring project translated into their inclination to implement costless actions for barn swallow conservation. Our findings suggest that the barn swallow monitoring project may not have enhanced farmers’ environmental consciousness. However, a higher environmental consciousness and the engagement in the barn swallow monitoring project were associated to a greater willingness to undertake actions in support of barn swallows. This study highlights the potential of long-term projects in fostering the conservation of charismatic species through establishing a mutual trust between farmers and researchers over years of monitoring, with cascading benefits for the barn swallows.

We present two new records of leucism in two bird species from two locations in Mexico. First, we report one leucistic Barn Swallow (Hirundo rustica); the individual was a nestling observed between 15 July and 6 August 2010, in a suburban area of central Jalisco, showing gray-whitish coloration and dark eyes. We also report of one leucistic Turkey Vulture (Cathartes aura) spotted during the afternoon of 4 November 2014, flying overhead while migrating in the city of José Cardel, Veracruz; the individual showed white primary feathers interspersed with dark secondaries, white primary coverts, white neck, and chest feathers. Our records represent the first Mexican report of leucism in the Barn Swallow, and the first published report of a leucistic vulture migrating across central Veracruz, respectively. Our observations also show that both leucistic individuals were accomplishing regular life-cycle activities, enriching the available knowledge of chromatic abnormalities in Mexican birds.

Although extensive research has been carried out on the occurrence of mercury (Hg) in biota, bioaccumulation and tissue distribution of Hg in songbirds have not been well characterized. In the present study, Hg was investigated in insects and barn swallows (Hirundo rustica) to explore the bioaccumulation characteristics of Hg. Hg in swallow feathers and tissues including muscle, liver, and bone was investigated to determine the tissue distribution of Hg. The concentrations of Hg were 1.39 ± 1.01 μg/g, 0.33 ± 0.09 μg/g, 0.47 ± 0.10 μg/g, and 0.23 ± 0.09 μg/g in feather, muscle, liver, and bone samples, respectively. The trophic magnification factor of Hg in swallows and insects was higher than 1. However, the Hg concentrations in swallow feathers were not significantly correlated with stable isotope values of carbon or nitrogen, which implies the complex food sources and exposure processes of Hg for swallows. Feathers had significantly higher concentrations of Hg than liver, muscle, and bone samples (p < 0.01 for all comparisons). Feather, muscle, bone, and other organs had fractions of 64.4 ± 11.9%, 6.07 ± 2.06%, 20.0 ± 8.19%, and 9.56 ± 2.96% in total body burden of Hg in swallows. Hg in feathers contributed more than half of Hg in the whole body for most swallow individuals. Swallows may efficiently eliminate Hg by molting, and the excretion flux of Hg and other contaminants via molting deserves more investigation. [ABSTRACT FROM AUTHOR]

The cost of ornamentation is often measured experimentally to study the relative importance of sexual and viability selection for ornamentation, but these experiments can lead to a misleading conclusion when compensatory trait is ignored. For example, a classic experiment on the outermost tail feathers in the barn swallow Hirundo rustica explains that the concave (or U‐shaped) aerodynamic performance cost of the outermost tail feathers would be the evolutionary outcome through viability selection for optimal tail length, but this conclusion depends on the assumption that compensatory traits do not cause reduced performance. Using a simple "toy model" experiment, I demonstrated that ornamentation evolved purely though sexual selection can produce a concave cost function under the presence of compensatory traits, which was further reinforced by a simple mathematical model. Therefore, concave cost function (and the low performance of individuals with reduced ornaments) cannot be used to infer the evolutionary force favoring ornamentation, due to a previously overlooked concept, "overcompensation," which can worsen the whole body performance. [ABSTRACT FROM AUTHOR]

Some theoretical models predict that nestling begging must be a costly activity to transmit reliable information to parents about offspring hunger. One candidate cost is oxidative stress, which could impair growth or immune function. This hypothesis predicts that nestlings in a poor oxidative status should pay higher costs for a given amount of begging, hence beg at lower rates for a similar degree of hunger. To test this prediction, we experimentally induced a transient alteration of the oxidative status of Barn Swallow (Hirundo rustica) nestlings by administering them either a single dose of a pro-oxidant substance (BSO) or an antioxidant (vitamin E), and recorded their begging behaviour. Chicks treated with vitamin E increased their begging rates in the hours following treatment. However, and contrary to prediction, BSO nestlings did not decrease begging compared to controls. These inconsistent results are difficult to explain by the hypothesis that begging performance is mediated by the oxidative status of nestlings because chicks with an impaired oxidative status (the BSO group) begged the same as controls. Alternatively, vitamin E may alleviate the inhibitory effects on begging of stress responses mediated by glucocorticoids. This study suggests that oxidative costs of begging are minor or absent in this species. Future studies should consider alternative explanations for an association between oxidative status, antioxidant supplementation and begging behaviour, particularly those involving glucocorticoids. [ABSTRACT FROM AUTHOR]

Parasite-mediated sexual selection has been the topic of extensive research and enthusiastic debate for more than three decades. Here, we suggest that secondary sexual characters may not only signal parasite resistance but also defensive tolerance. We exemplify this possibility by analysing information on two sexually selected traits, annual reproductive success, and ectoparasitism in a barn swallow Hirundo rustica population followed for more than 30 years. For each individual, we estimated the slope of the association between reproductive success and parasitism as an index of tolerance and subsequently explored the association with the expression of the sexually selected traits. In accordance with expectations of parasites playing a role in sexual selection, tail length was negatively related to load of chewing lice and nest size was positively related to tolerance to chewing lice. We discuss the importance of considering defensive tolerance for understanding the role of parasite-mediated sexual selection. [ABSTRACT FROM AUTHOR]

"Nestwork: New Material Rhetorics for Precarious Species" by Jennifer Clary-Lemon explores the concept of ecological care in the face of species extinction. The author challenges anthropocentric and human exceptionalist perspectives on rhetoric, drawing on posthumanism, new materialism, and Indigenous ways of knowing. The book examines efforts to support Canada's barn swallows, chimney swifts, and bobolinks, highlighting the complexities of coexistence in the Anthropocene. Clary-Lemon argues for the importance of reimagining and remaking our relationships with both human and more-than-human others in order to thrive in the future. [Extracted from the article]

Brood parasitic birds lay eggs in the nests of other birds, and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic eggs. Hosts can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host eggs. However, there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision rules. In this study, we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows (Hirundo rustica) of two geographical populations breeding in Hainan and Heilongjiang Provinces in China. Results showed that Barn Swallows rejected more white model eggs (moderate mimetic to their own eggs) and blue model eggs (highly non-mimetic eggs with shorter reflectance spectrum) than red model eggs (highly non-mimetic eggs with longer reflectance spectrum). There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows, and clutch size was not a factor affecting egg recognition. Our results are consistent with the single rejection threshold model. This study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows, opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.

Urbanization affects the natural world, with implications for habitat availability and wildlife behavior, notably in the context of South Korea. This study investigates the effects of urbanization on the nest sizes and materials of barn swallows, a migratory bird species. Utilizing comparative analyses across suburban, exurban, and rural regions, the study found substantial variations in nest volumes. Specifically, rural areas had significantly larger nests than suburban areas, whereas exurban nest sizes fell in between. Although a potential explanation might relate to differences in the availability of nesting materials, this hypothesis necessitates further investigation. The study also found that the soil composition in nests varied by location, with sand, silt, and clay content showing marginal differences, but not statistically significant disparities. However, a clear preference for a specific soil texture was evident, along with the finding that forest cover within a 1 km radius of the nest was correlated with larger nest sizes. Land use was further linked to the external volume of barn swallow nests, pointing to a potential interaction between habitat quality and nest construction. Overall, the findings underscore the complexity of urbanization's impact on barn swallows, emphasizing the need to conserve natural habitats and devise strategies to mitigate the negative effects on these birds. These results contribute to the growing understanding of urban ecology and the urgent need for thoughtful management of human-altered landscapes. [ABSTRACT FROM AUTHOR]

Copyright of Veterinarska Stanica is the property of Croatian Veterinary Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Birds are commonly used as bioindicators, and their feathers are considered suitable tissues for assessing the presence of contaminants, such as trace elements, in the environment. In agroecosystems, trace elements' occurrence can be associated with both natural and anthropogenic processes, including vehicular traffic, traditional fertilizers, food feed additives for livestock, and the use of sewage sludge as fertilizer. Here, we evaluated the concentrations of twelve trace elements (Aluminium, Arsenic, Cadmium, Chromium, Copper, Iron, Mercury, Manganese, Nickel, Lead, Selenium, and Zinc) in the feathers of barn swallow (Hirundo rustica) nestlings. We then compared the concentrations of these elements between nestlings grown in areas amended or not amended with sewage sludge in 2019 and 2020 in a broad region of the Po Plain (Northern Italy). Multivariate analysis showed that the element content of the feathers significantly differed among years and areas, suggesting that the concentration of nestlings' feathers may indicate the local level of contamination. However, univariate analyses did not show clear spatial differences, possibly due to co-occurring sources of trace elements other than sewage sludge. These results suggest that barn swallow nestlings can be a reliable sentinel for the monitoring of local variation of the environmental occurrence of trace elements. [ABSTRACT FROM AUTHOR]

Aerial insectivorous birds have suffered steep population declines in North America over the last 60 years. A lack of information on migratory connectivity between breeding and non-breeding grounds for these species limits our ability to interpret factors affecting their population-specific trends. We determined likely Latin American non-breeding regions of Bank (Riparia riparia), Barn (Hirundo rustica) and Cliff (Petrochelidon pyrrhonota) swallow from populations across their breeding ranges. We used predicted feather hydrogen (δ2Hf) and carbon (δ13Cf) isoscapes for winter-grown feathers to indicate areas of highest probability of moult origin and incorporated these results into a cluster analysis to determine likely broad non-breeding regions. We also assessed variation in wing length among populations to determine the potential for this metric to differentiate population moult origins. We then investigated patterns of multi-isotopic (δ2Hf, δ13Cf, δ15Nf) and wing-length niche occupancy by quantifying niche size and overlap among populations under the assumption that broad niches were consistent with low within-species migratory connectivity and narrow and non-overlapping niches with higher connectivity. Multivariate assignment identified different non-breeding regions and potential clusters of moult origin generally corresponding to Central America and northern South America, eastern and south-central South America, and the western and southern part of that continent, with variation within and among populations and species. Separate niche space indicated different wintering habitat or areas used by species or populations whereas niche overlap indicated only potential spatial similarity. Wing length varied significantly among populations by species, being longer in the west and north for Bank and Cliff Swallow and longer in eastern Canadian Barn Swallow populations. Barn Swallow occupied consistently larger isotopic and wing length niche space than the other species. Comparisons among populations across species showed variable isotopic and wing-length niche overlap generally being greater within breeding regions and lower between western and eastern breeding populations supporting a general North American continental divide for all species with generally low migratory connectivity for all species. We present a novel approach to assessing connectivity using inexpensive and broad isotopic approaches that provides the basis for hypothesis testing using more spatially explicit expensive techniques. [ABSTRACT FROM AUTHOR]

Reproduction and self-maintenance are energetically costly activities involved in classic life history trade-offs. However, few studies have measured the responses of wild organisms to simultaneous changes in reproductive and self-maintenance costs, which may have interactive effects. In free-living female Barn Swallows (Hirundo rustica), we simultaneously manipulated reproductive costs (by adding or removing two nestlings) and self-maintenance costs (by attaching a ∼1 g weight in the form of a GPS tag to half of our study birds) and measured mass, immune status, blood glucose, feather growth, and reproductive output (likelihood of a second clutch, number of eggs, and time between clutches). GPS tags allowed us to analyze how movement range size affected response to brood size manipulation. Tagging altered females' immune function as evidenced by an elevated heterophil to lymphocyte (H:L) ratio, but all females were equally likely to lay more eggs. There was no evidence of interactive effects of the tagging and brood size treatment. Range size was highly variable, and birds with large ranges grew feathers more slowly, but analyzing the effect of brood size manipulation while accounting for variation in range size did not result in any physiological response. Our results support the theoretical prediction that short-lived vertebrates do face a trade-off between reproduction and self-maintenance and, when faced with increased costs, tend to preserve investment in reproduction at the expense of parental condition. This experiment also helps us to understand how movement patterns may be relevant to life history trade-offs in wild birds. [ABSTRACT FROM AUTHOR]

The knowledge of migratory connectivity is important for understanding the potential drivers of populations and it is thus important for conservation implications. Migratory connectivity of species can be studied using exogenous, such as rings and transmitters, or endogenous markers, such as stable isotopes and trace elements. The use of trace elements has been much less frequently studied compared to stable isotopes. Trace elements can be studied from the feathers of birds and this does not necessarily require trapping of individuals. Here we studied the variation of 18 different trace elements in feathers of two long‐distance trans‐African migrants, willow warblers Phylloscopus trochilus and barn swallows Hirundo rustica, using body feathers of museum specimens of birds from Finnish breeding grounds. The trace elements were measured using laser‐ablation inductively‐coupled‐plasma mass‐spectrometry (LA‐ICP‐MS). We show that trace element concentrations were relatively stable along the rachis within the same feather except in Ni and S, which showed a quadratic pattern. In general, variation within feathers of the same individuals was smaller than in feathers between individuals for most elements. Furthermore, concentrations of 11 trace elements showed significantly higher concentrations in willow warbler feathers collected in spring than in autumn, moulted in African wintering grounds and European breeding grounds, respectively. Last, concentrations of seven trace elements were significantly higher in the spring feathers of willow warblers compared to barn swallows. This suggests that trace elements could be used to separate moulting grounds of the birds on the larger scale within the same species, but also sampling design should be carefully considered. [ABSTRACT FROM AUTHOR]

The function of female ornamentation in (inter)sexual selection is attracting increasing attention, but empirical field studies are mostly based on indirect measures such as mating patterns; direct evidence of male mate preference on female ornamentation while controlling for confounding factors is needed. Here, we performed model presentation experiments to study male mate preference in the barn swallow Hirundo rustica, a model species of sexual selection. Although female tails are shorter than male tails in the barn swallow, they are still long and indicate female quality, possibly due to the differential costs of ornamentation. Although many correlational and experimental studies of live females have focused on long tails in female barn swallows over the last three decades, direct behavioral tests of male mate preference are lacking. In our sequential model presentation experiment, in which we repeated the trials with the same males, we found that males significantly reduced the number of pairing displays when presented with tail‐elongated female models compared to controls. The interaction between treatment and male tail length was far from significant. The observed pattern is inconsistent with the prevailing view that female ornamentation is maintained via male preference for more ornamented females; rather, it is consistent with the sexual mimicry hypothesis, in which females can avoid sexual and social harassment by mimicking males. [ABSTRACT FROM AUTHOR]

Recent insect abundance declines may have affected populations of insectivorous bird species but evidence for this is limited. Here, we use spatially overlapping 29‐year time‐series of aerial insect biomass and Barn Swallow Hirundo rustica numbers and breeding success from southern England to model the association between changes in invertebrate prey abundance, Swallow productivity and population trends. We found a positive statistical relationship between Swallow chick survival and the biomass of aerial insects available for chicks. In nests where at least one chick fledged, 96.7% of chicks were predicted to survive to fledging where there was high insect biomass (an average of 0.62 g/day), compared with 87.4% of chicks surviving to fledging where there was the lowest insect biomass (0.02 g/day; excluding the greatest and smallest 5% of insect biomass measurements). The amount of food available for chicks was largely a function of annual variation in insect abundance rather than the phenology of egg‐laying and insect emergence. However, we did not find a correlation between annual insect abundance and subsequent Swallow population growth. In the context of concerns about declining insect abundance, this study shows how changes in insect biomass may affect the productivity of an insectivorous bird at a regional scale, but with uncertain implications for population size at that same scale. [ABSTRACT FROM AUTHOR]

According to classical prediction of aerodynamic theory, birds and other powered fliers that migrate over long distances should have longer and more pointed wings than those that migrate less. However, the association between wing morphology and migratory behavior can be masked by contrasting selective pressures related to foraging behavior, habitat selection and predator avoidance, possibly at the cost of lower flight energetic efficiency. We studied the handwing morphology of Eurasian barn swallows Hirundo rustica from four populations representing a migration distance gradient. This species is an aerial insectivore, so it flies extensively while foraging, and may migrate during the day using a 'fly-and-forage' migration strategy. Prolonged foraging flights may reinforce the effects of migration distance on flight morphology. We found that two wings' aerodynamic properties—isometric handwing length and pointedness, both favoring energetically efficient flight, were more pronounced in barn swallows from populations undertaking longer seasonal migrations compared to less migratory populations. Our result contrast with two recent interspecific comparative studies that either reported no relationship or reported a negative relationship between pointedness and the degree of migratory behavior in hirundines. Our results may thus contribute to confirming the universality of the rule that longer migrations are associated with more pointed wings. [ABSTRACT FROM AUTHOR]

Copyright of Acta Zoologica Lilloana is the property of Fundacion Miguel Lillo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Early life for animals is often a time of rapid growth and development. In a resource-limited environment, life history theory predicts that there must be trade-offs between resource sinks in ways that optimize future survival and reproductive success. Telomeres have emerged as putative indicators of these early life trade-offs, but there are conflicting accounts as to how developmental traits and conditions impact telomere length and dynamics. For 2 years, we studied the nestlings of a breeding population of barn swallows from day 6 to day 12 of life, measuring various ontogenetic factors to understand to what extent they explain variation in telomere length and dynamics. We unexpectedly found that telomeres lengthened between the two sampling points. Nestlings in large broods had shorter telomeres, but surprisingly, individuals that grew faster from day 6 to day 12 had longer telomeres and more telomere lengthening. Nestlings with higher mass relative to their nestmates on d6 had shorter telomeres, suggesting that the relatively fast growth barn swallows experience early in development is more costly than the relatively slower growth later in development. These effects were only found in the first year of study. Telomere lengthening may be due to the initiation of new hematopoietic cell lines during development or the expression of telomerase early in life. Favorable early life conditions and high parental investment could allow for more growth with little to no cost to telomere length or dynamics. [ABSTRACT FROM AUTHOR]

Hosts defend against parasites through two main strategies: resistance and tolerance. These two strategies have different influences on the parasite load of the host and so have variable effects on the fitness of parasites. In this study, we investigated the strategy used by the Barn Swallow (Hirundo rustica) to defend against a hematophagous mite (Dermanyssus hirundinis) in East Asia. For the first time, we found Barn Swallows were parasitized by D. hirundinis in Asia and, in northeastern China, over 60% of broods were parasitized. We examined whether swallows with better body condition or the males with more extravagant sexually selected traits (longer tail streamers or redder ventral plumage) showed stronger resistance or tolerance to these parasites. The results showed that males with more extravagant sexual ornaments had weaker resistance (heavier brood mite load) than males with less extravagant traits; however, the heavier mite load was likely to be a byproduct of larger brood size. Moreover, the Barn Swallow population showed strong tolerance against the parasite (i.e. the brood mite load did not affect brood size or nestling body mass). It is worth noting that male swallows with redder breast plumage showed weaker tolerance (lower seasonal reproductive success) than other males. Further, we conducted experimental ectoparasite manipulations in 46 Barn Swallow nests to verify the potential effect of these parasites on the body condition of nestlings. Neither the body mass nor the hemoglobin concentration differed between the designed groups; however, the hemoglobin concentration of nestlings decreased with mite load. We concluded that the Barn Swallow population in East Asia used the tolerance strategy, rather than resistance to defend against nest mites, and the ectoparasitic mite did not appear to be a strong selective factor for reproductive success owing to the strong tolerance of the studied Barn Swallow population. [ABSTRACT FROM AUTHOR]

Many studies of animal and plumage coloration use spectrometry to obtain objective measurements of colorful traits. Objective measurements of plumage color are particularly important as the avian visual system is distinct from our own and subjective color assessment by researchers can miss important color variation or signals. As spectrometry has become one of the preferred methods of color measurement, appropriate methodologies and reporting standards have refined and improved the technique as well as increased our ability to make comparisons across studies. Here, we investigate another important methodological decision by examining how the background color against which feather samples are measured impacts the reflectance spectra and color descriptors commonly extracted from those spectra. We used feather samples collected from Eastern Bluebirds (Sialia sialis) and Barn Swallows (Hirundo rustica erythrogaster) to determine how black and white backgrounds influence color measurements. We measured the same feather sample in the same arrangement against a white index card and a piece of black cardstock and found that measurements taken against a white background tended to yield higher reflectance curves, which also resulted in significant differences in some color descriptors. Lightly colored, wispy, and small feathers seem to be particularly susceptible to background color effects. Thus, researchers using spectrometry to measure colorful traits should carefully consider the background against which they are taking measurements as white backgrounds tend to increase reflectance and certain feather colors or morphology (light and wispy) may be particularly susceptible to spectral contamination. Muchos estudios sobre coloración animal y del plumaje utilizan la espectrometría para obtener medidas objetivas de rasgos de color. Las medidas objetivas del color del plumaje son particularmente importantes debido a que el sistema visual de las aves es distinto del nuestro y la evaluación subjetiva del color por parte de los investigadores puede omitir algunas variaciones importantes del color o en señales de color. A medida que la espectrometría se ha convertido en uno de los métodos preferidos para medir el color, las metodologías apropiadas y los estándares para reportarlo se han ido refinando y mejorando su técnica, además de incrementar nuestra capacidad para realizar comparaciones entre estudios. En este trabajo investigamos otra decisión metodológica importante a la hora de examinar cómo el color del fondo contra el que se miden las muestras de afecta el espectro de reflectancia y a los descriptores de color comúnmente extraídos de dichos espectros. Usamos muestras de plumaje recolectadas de azulejos (Sialia sialis) y golondrinas (Hirundo rustica erythrogaster) para determinar cómo un fondo blanco y uno negro influyen en las medidas de color. Medimos la misma muestra de plumas en la misma disposición contra una tarjeta de cartulina blanca y una tarjeta negra, y encontramos que las medidas tomadas contra un fondo blanco tendían a producir curvas de reflectancia más altas, lo que también produjo diferencias significativas en los descriptores de color. Las plumas pequeñas, delgadas y de colores claros parecen ser particularmente susceptibles a los efectos del color del fondo. Por lo tanto, los investigadores que utilizan la espectrometría para medir rasgos de color deben considerar con cuidado el fondo contra el cual están tomando medidas, debido a que los fondos blancos tienden a aumentar la reflectancia y ciertos colores o morfologías (ligeras y tenues) de plumas pueden ser particularmente susceptibles a la contaminación espectral. Palabras clave: coloración animal coloración del plumaje espectrometría medición del color métodos reflectancia [ABSTRACT FROM AUTHOR]

Background: Mycoplasmas are found in many different species. Until now 26 avian mycoplasma species have been described, but in the most free ranging bird species the prevalence and significance of Mycoplasma spp. is still unclear. Case presentation: In May 2021 a barn swallow (Hirundo rustica) was brought to a veterinary clinic after it hit a window. As part of the routine exam a choanal swab was taken for mycoplasma culture and for the detection of mycoplasmas using a Mycoplasma-genus-specific Polymerase chain reaction. Six single colony subcultures were obtained by the cultivation. Obtained subcultures were investigated by sequencing the 16S rRNA and the 16S-23S rRNA intergenic transcribed spacer region sequence. The 16S rRNA gene sequence from one subculture had a homology of 99.03% and the 16S-23S rRNA intergenic transcribed spacer region sequence of 100% with the sequence of Mycoplasma sturni. The 16S rRNA gene sequence from the other five subcultures shared a homology of 99.89% and the 16S-23S rRNA intergenic transcribed spacer region sequence of 99.81% with the sequence of Mycoplasma moatsii. Conclusions: According to the available literature this is the first report about the detection of M. moatsii, in the respiratory tract of a barn swallow. M. moatsii was previously only found in grivit monkeys (Cercopithecus aethiops), Norway rats (Rattus norvegicus) and a mute swan (Cygnus olor). The role of mycoplasmas in barn swallows is still unknown, especially as in the present case both mycoplasma species do not seem to cause clinical symptoms. [ABSTRACT FROM AUTHOR]

The habitat type and food availability always influence the population size of many organisms. Bird’s feeding pattern should be abstracted to complete avian community structure data. The agronomy main research farm of Orissa University of Agriculture and Technology is a well-managed multi-crop agro-ecosystem which provides a suitable ground for ecological research. In a multi-crop farmland, the association of Barn Swallow Hirundo rustica Linnaeus, 1758,with the Indian mustard Brassica juncea (L.) Czernajew, 1859 cropshave been recorded for the first time while hovering only on this field. A flock of Barn swallows was recorded in 32 field visits while flying continuously over the Indian mustard field after flowering to ripening of fruit in the morning and sometimes in afternoon also. The range of the birds was recorded from 6 to 61 with a mean individual of 36.03 ± 15.37 hovering for 1.83 hr daily. This may be the behaviour for the feeding pattern of these flying insectivorous birds which was not seen in other crop-fields with same insect diversity describing it as not the only reason for this behaviour. To reveal this poorly understood behaviour offlying insectivore birds, a detailed long term behavioural study with gut content analysis is needed to explain the particular reason behind this behaviour of Barn swallows which will support the conservation of these birds and control their population decline.

Background: Central European aerial insectivores are long-distance migrants that winter in sub-Saharan Africa. Most of them employ the fly-and-forage migrating strategy and differ in their food composition. The composition and structure of helminth component communities of these hosts are poorly understood, and information regarding seasonality and long-term changes is unavailable. Methods: From 1963 to 2022, we analyzed the population trends of helminths in five aerial insectivore species. Namely, we examined Apus apus, Hirundo rustica, Delichon urbicum, Riparia riparia, and Ficedula albicollis; all originated from the Czech Republic. Results: We identified central European aerial insectivores as hosts that are parasitized mostly by helminths that cannot complete their life-cycles in the nesting quarters of their hosts. This phenomenon is unknown in other bird host species. In contrast, only a single dominant trematode species that completes its life-cycle locally colonized the central European aerial insectivores. All other dominant species of Trematoda, all Nematoda, and all Acanthocephala were dependent on intermediate hosts unavailable in the nesting quarters of the examined bird hosts. Surprisingly, these helminths transmitted from winter quarters or migratory routes were diverse, and many of them were abundant in terms of both prevalence and intensity of infection. The helminth component communities of aerial insectivores were dynamic systems. During the study period, three species became new and regularly encountered members of helminth fauna of examined hosts, and other species gradually increased or decreased their intensity of infection. In contrast to other groups of bird hosts, the dominant helminth species of aerial insectivores did not experience local extinctions or rapid population losses. Conclusions: The analysis of helminths of five central European aerial insectivores revealed component communities that heavily rely on completing host–parasite cycles at migration routes or wintering grounds. The composition of the analyzed component communities changed dynamically during the 60-year-long study period, but there was no evidence of large-scale declines in abundance or prevalence. [ABSTRACT FROM AUTHOR]

Farmland biodiversity is declining at an alarming rate and various conservation measures have been implemented to reverse this negative trend. Farmsteads within agricultural landscapes were recently identified as farmland bird hotspots, so we ask whether the modernization of farmsteads has substantially reduced their conservation potential for farmland birds.We assessed the effect of farmstead modernization on 29 farmland bird species in rural landscapes on 97 dairy farms across the Czech Republic, investigating differences in farmland bird abundance and species richness, as well as nest abundance of declining farmland species breeding in buildings, by comparing new/modernized with old and mixed farmsteads. Additionally, we investigated how farmstead size and environmental variables influenced avian assemblages on farmsteads.Farmland bird abundance was almost 3‐fold lower in new/modernized farmsteads compared to mixed and old farmsteads (this difference was mostly driven by building‐nesters and noncrop‐nesters). Similarly, species richness was higher in old and mixed farmsteads compared to new farmsteads. Old cow sheds hosted more nests (both old and new nests; by a factor of 1.6–21) of house sparrows Passer domesticus, barn swallows Hirundo rustica and house martins Delichon urbicum compared to new cow sheds.Importantly, effects of environmental variables were negligible or smaller compared to the farmstead type, suggesting that bird abundance and species richness on farmsteads was primarily driven by farmstead modernization rather than the structure of surrounding farmland.Synthesis and applications. Farmstead modernization may have strong adverse effects on farmland bird populations due to reducing the availability of critical high‐quality nesting and foraging opportunities. Modernization is largely financed from existing EU funds, which directly conflicts with EU biodiversity strategies aiming at halting biodiversity loss. We therefore recommend (i) including compensatory measures to increase nesting and foraging opportunities for birds during farmstead construction/modernization, (ii) increasing awareness of these problems among critical stakeholders and (iii) increasing support to small‐sized traditional farms to retain and improve habitat conditions for declining farmland species. [ABSTRACT FROM AUTHOR]

Simple Summary: Barn Swallows (Hirundo rustica) mainly breed in temperate regions and parts of the tropics. These two regions have remarkably different environments, especially pertaining to their weather conditions. It is interesting to see how the breeding performances of Barn Swallows differ between the two regions and how the weather conditions affect the reproductive success of the Barn Swallow. We monitored the breeding activities of two Barn Swallow populations simultaneously in both tropical and temperate regions in China from 2019 to 2021 and investigated the effects of weather conditions on the reproductive success of the Barn Swallow in the study sites. We found that the reproductive success of the Barn Swallow at the tropical site was lower than that at the temperate site, i.e., swallows at the tropical site laid fewer eggs and had fewer nestlings/successful breeding attempts than swallows at the temperate site. Temperature, rather than rainfall, influenced the breeding performances of Barn Swallows at both sites. In particular, nestling survival decreased with increasing temperatures at the tropical site, but not at the temperate site. We suggest that researchers pay more attention to the reproduction and population changes of the Barn Swallow in the tropics in the context of climate warming. Temperate–tropical comparisons of avian life history traits are helpful to understand the different selective pressures placed on birds by different climate zones. Although there have been many comparative studies targeting multiple species in different regions, there are few comparative studies on the reproductive successes of the same species between tropical and temperate regions. In this study, we monitored the breeding activities of the Barn Swallow (Hirundo rustica) simultaneously at a single tropical site and a single temperate site in China, compared the breeding performances of the two populations, and investigated the effects of weather conditions on reproductive success separately. The clutch and brood sizes of the Barn Swallow at the topical site were significantly smaller than those at the temperate site. Furthermore, the breeding success of the Barn Swallow at the tropical site was significantly lower than that at the temperate site. The mean daytime temperature had a negative effect on the clutch size and brood size at both sites; it had a negative effect on nestling survival at the tropical site, but not the temperate site. This study will help us understand the adaptation strategies of widely distributed bird species in different environments, and how climate change will affect birds in different climate zones. [ABSTRACT FROM AUTHOR]

This work consists of analyzing the Barn Swallows nest's soil (Hirundo Rustica) which was nested in the northeastern Algeria, particularly in the Mila region (Beinen), the Guelma region (Town-Center and Bouchegouf) and, the Oum El Bouaghi region (Ain el Baida). This species of birds uses different materials to build their nests, whose main component is the existing meadow soil. This study is contributes to knowing the bird strategy on nest building and materials chosen in it. From there, we have done weight chemical analysis according to the Vatan model; the results obtained are represented in the Czerminski diagram; for the organic matter quantification, we have used Walkley and Blacket method, and ecological analysis was according to ANOVA model. The weight chemical analysis results showed us loamy sandstone or marly sandstone soil type on the Northside of the study area (Mila region) and marly sandstone, sandy-marly loams, marl, and marly-sandy limestones on the Southside of the study area (Guelma and Oum El Baouaghi region), the organic matter analysis results showed non-aggressive soils and the ecological analyzes revealed a significant difference between the nest's compositions of each region except for the loam which has an F = 1.4857 and P = 0.2681. So, the Barn Swallows have a very precise strategy in choosing construction materials for their nests. For that, we recommend to characterize those construction materials by other studies (plasticity, mechanical resistance, mineralogy etc.). [ABSTRACT FROM AUTHOR]

Quantifying an individual's state as a fitness proxy has proven challenging, but accumulating evidence suggests that telomere length and attrition may indicate individual somatic state and success at self‐maintenance, respectively. Sexual ornamentation is also thought to signal phenotypic quality, but links between telomeres and sexual ornamentation have been little explored. To address this issue, we examined whether telomere length and dynamics are predicted by the expression of a sexually selected ornament, the length of the outermost tail feathers (streamers), using longitudinal data from a population of European barn swallows (Hirundo rustica). In 139 adult individuals, each measured twice, we further assessed associations of telomere length with age, sex, breeding status and survival. Telomere length showed high individual repeatability (R =.97) across years while shortening with age in both sexes. Telomere length and dynamics were not significantly associated with survival to the next year, remaining lifespan or reproduction status (comparing breeding and nonbreeding yearlings). Tail streamer length, a sexually selected trait in barn swallows, was negatively associated with telomere length, independent of sex. Thus, telomere length may reflect the costs of carrying an elaborated sexual ornament, although ornament size did not significantly predict telomere shortening. In conclusion, telomere length in adult barn swallows is a highly consistent trait that shows a negative relationship with sexual ornamentation, suggesting a trade‐off between sexual ornamentation and telomere length. [ABSTRACT FROM AUTHOR]

Nest site selection is critical for reproductive success in birds. Several bird species including Barn Swallow (Hirundo rustica gutturalis) typically nest near human settlements, presumably because this reduces their risk of predation. Here, we investigated the nesting habits of Barn Swallows in South Korea. We predicted that abandoned houses would not be chosen even if these houses provided similar nesting conditions compared to occupied houses. We conducted surveys across South Korea and recorded human occupancy, house structure, the number of active and old nests, and the deterioration condition of houses. Among the recorded active nests, 95% were located in inhabited houses (n = 38), whereas only 5% were observed in abandoned houses (n = 2). Interestingly, human presence was a significant factor in the occurrence of active nests, whereas house structure had no appreciable effect. Among the nest site characteristics, the number of old nests was significantly higher in inhabited houses than in abandoned houses. Further, ∼97% of inhabited houses were not damaged, whereas 50% of the abandoned houses were damaged, potentially affecting the nesting site selection of Barn Swallows. Our results are consistent with our hypothesis that Barn Swallows prefer to nest in human-inhabited houses. As house structures suitable for nesting are reduced due to rapid urbanization, and as swallow nests are actively eliminated by human residents, the reproductive success of Barn Swallows in South Korea can be significantly reduced. [ABSTRACT FROM AUTHOR]

Keywords: algerian sahara; biodiversity; birds; first breeding; hirundo rustica; indicator species; North Africa EN algerian sahara biodiversity birds first breeding hirundo rustica indicator species North Africa 1283 1286 4 11/30/22 20221201 NES 221201 INTRODUCTION The barn swallow is an anthropophilic species closely associated with humans (Cramp, 1998; Turner, 2006). Breeding biology of barn swallows Hirundo rustica in Algeria, North Africa. [Extracted from the article]

Background: The spatiotemporal organization of migratory routes of long-distance migrants results from trade-offs between minimizing the journey length and en route risk of migration-related mortality, which may be reduced by avoiding crossing inhospitable ecological barriers. Despite flourishing avian migration research in recent decades, little is still known about inter-individual variability in migratory routes, as well as the carry-over effects of spatial and temporal features of migration on subsequent migration stages. Methods: We reconstructed post- and pre-breeding migration routes, barrier crossing behaviour and non-breeding movements of the largest sample (N = 85) analysed to date of individual barn swallows breeding in south-central Europe, which were tracked using light-level geolocators. Results: Most birds spent their non-breeding period in the Congo basin in a single stationary area, but a small fraction of itinerant individuals reaching South Africa was also observed. Birds generally followed a 'clockwise loop migration pattern', moving through the central Mediterranean and the Sahara Desert during post-breeding (north to south) migration yet switching to a more western route, along the Atlantic coast of Africa, Iberia and western Mediterranean during the pre-breeding (south to north) migration. Southward migration was straighter and less variable, while northward migration was significantly faster despite the broader detour along the Atlantic coast and Iberia. These patterns showed limited sex-related variability. The timing of different circannual events was tightly linked with previous migration stages, considerably affecting migration route and speed of subsequent movements. Indeed, individuals departing late from Africa performed straighter and faster pre-breeding migrations, partly compensating for the initial departure delays, but likely at the cost of performing riskier movements across ecological barriers. Conclusions: Different spatiotemporal migration strategies during post- and pre-breeding migration suggest that conditions en route may differ seasonally and allow for more efficient travelling along different migration corridors in either season. While highlighting patterns of inter-individual variability, our results support increasing evidence for widespread loop migration patterns among Afro-Palearctic avian migrants. Also, they suggest that carry-over effects acting across different phases of the annual cycle of migratory species can have major impacts on evolutionary processes. [ABSTRACT FROM AUTHOR]

The article presents the discussion on abundance of the Barn Swallow. Topics include decline of North American avifauna being well documented and the loss being prominent among passerines; and various factors implicated in the decline of insect populations showing the use of agro-chemicals and the frequency of severe storms increasing with climate change.

Simple Summary: Most birds build nests for laying eggs and rearing their offspring. They frequently clean their nests by removing foreign objects, such as leaves, small branches, stones, and feces. Further, some birds recognize and remove foreign eggs deposited by brood parasites. Nest sanitation and egg rejection are related behaviors as both impact brood survival and involve an accept/reject decision regarding the content of the nest. Here, we examined these behaviors in barn swallows (Hirundo rustica), one of the most abundant and widespread birds in the world. The results suggest that nest sanitation may be a more ancient behavior because it occurs more frequently, and foreign objects were removed sooner upon discovery than egg rejection. Therefore, nest sanitation may constitute an evolutionary precursor to foreign egg rejection; however, nest sanitation rarely increases egg rejection regarding probability and response latency. Female and male swallows engaged in nest sanitation and egg rejection, implying that both sexes are affected by this type of natural selection. Bird nests function as vessels for eggs and nestlings, and an environment for rearing offspring. However, foreign objects falling into bird nests and nestling eggshells may be harmful. Moreover, the smell of fecal sacs increases the risk of detection by predators. Many bird species have evolved nest sanitation to prevent damage to their nests. Furthermore, egg rejection evolved in some birds to thwart brood parasites that lay eggs in their nests. We studied 133 nests of barn swallows (Hirundo rustica) in an island population through a nest content manipulation experiment to determine nest sanitation and egg rejection behaviors and their relationship. Swallows rejected non-egg foreign objects more frequently (100% vs. 58.6%) and sooner than parasite eggs, which supports the hypothesis that nest sanitation is a pre-adaptation to egg rejection. However, nest sanitation did not increase egg rejection, either in probability or latency. Furthermore, both sexes incubated the eggs, cleaned the nests, and removed parasite eggs, implying that both are confronted with natural selection related to nest sanitation and brood parasitism. However, females invested more time in these behaviors than males. This provides evidence for the evolutionary relationship of nest sanitation and egg rejection behaviors in barn swallows. [ABSTRACT FROM AUTHOR]

Quality and quantity of food items consumed has a crucial effect on phenotypes. In addition to direct effects mediated by nutrient resources, an individual's diet can also affect the phenotype indirectly by altering its gut microbiota, a potent modulator of physiological, immunity and cognitive functions. However, most of our knowledge of diet-microbiota interactions is based on mammalian species, whereas little is still known about these effects in other vertebrates. We developed a metabarcoding procedure based on cytochrome c oxidase I high-throughput amplicon sequencing and applied it to describe diet composition in breeding colonies of an insectivorous bird, the barn swallow (Hirundo rustica). To identify putative diet-microbiota associations, we integrated the resulting diet profiles with an existing dataset for faecal microbiota in the same individual. Consistent with previous studies based on macroscopic analysis of diet composition, we found that Diptera, Hemiptera, Coleoptera and Hymenoptera were the dominant dietary components in our population. We revealed pronounced variation in diet consumed during the breeding season, along with significant differences between nearby breeding colonies. In addition, we found no difference in diet composition between adults and juveniles. Finally, our data revealed a correlation between diet and faecal microbiota composition, even after statistical control for environmental factors affecting both diet and microbiota variation. Our study suggests that variation in diet induce slight but significant microbiota changes in a non-mammalian host relying on a narrow spectrum of items consumed. [ABSTRACT FROM AUTHOR]

The length of the ornamental tail rectrices has been shown to be an important condition-dependent sexually selected trait in various bird species. Similarly, the shape and depth of the tail fork may represent a costly sexual signal that enhances individual attractiveness but compromises flight manoeuvrability. Avian flight feathers, including ornamental rectrices, generally become longer in successive years. In this study, we analysed age and sex differences in the length of central tail feathers and the depth of the tail fork in 141 Barn Swallows observed repeatedly over consecutive years. As expected, tail fork depth was mainly determined by the length of the outer ornamental tail streamers and to some extent to the non-ornamental central feathers, with individuals with deeper forks having longer outer streamers and shorter central tail feathers. Central tail feathers were sexually dimorphic and shorter in males than females. We also found an unexpected pattern of shortening of central tail feathers with increasing age that contributed to an age-related increase in tail fork depth in both sexes. The shortening of central tail feathers was achieved by the reduction of daily feather growth rates and not by feather abrasion. To the best of our knowledge, our study provides the first evidence of age-related continuous shortening of flight feathers in an avian species and suggests a possible sexual role of central tail feather length in Barn Swallows. [ABSTRACT FROM AUTHOR]