Swallow Hirundo Research Articles

An Updated Checklist of Avifauna found in and around Chilika Lake, Odisha, India

Chilika lake is one among the 467 important bird area (IBA) sites in India. The present study addresses the updated checklist ofavifauna of Chilika Lake, which is world's second largest brackish water Lake. Surveys were conducted during October 2006 and December 2016.The birds were recorded during the total count by boat, walking along the shore, block count, bird ringing, banding and satellite telemetry techniques. A total of 222 species ofavifauna of 62 orders and 20 families were recorded in and around study area. Nine (9) new bird species (River Lapwing Vanellus duvaucelli, Glossy Ibis Plegadis facinellus, Indian Thick-knee Burhinus indicus, Alexandrine Parakeet Pstittacula eupatria, Chestnut-headed Beeeater Merops leschenaultia, Wire-tailed Swallow Hirundo smithii, Whiterumped Munia Lonchura striata, Scaly-breasted Munia Lonchura punctulata and Black-hooded Oriole Oriolus xanthornus) were recorded first time in the study area. Out of total documented species, most of them were Least concern (201) followed by Near Threatened (17), Vulnerable (2) and Endangered (2) category of the International Union of Conservation of Endangered Fauna and Flora. The endangered species recorded from the study area were Pallas's fish eagle (Haliaeetus leucoryphus) and Great knot (Calidris tenuirostris). Prawn gharries, poaching, poisoning, illegal fishing, over fishing (operate zero size mesh net), habitat degradation and otheranthropogenic activities are the major threat to the conservation of avifauna in and around Chilika lake.

Natal dispersal and recruitment of Barn Swallows Hirundo rustica in an urban habitat

ABSTRACT Capsule Barn Swallow Hirundo rustica nestlings exhibited higher local recruitment when the body mass was high and when raised in an artificial nest early in the breeding season. Aims To determine natal dispersal and recruitment of Barn Swallows breeding in artificial nests and natural nests in an urban habitat. Methods During the breeding seasons of 2012–2018 a total of 3907 Barn Swallow nestlings were ringed and in the breeding seasons of 2016–2019 adult Barn Swallows were recaptured to assess natal dispersal distances and local recruitment. Results Female Barn Swallows dispersed from their natal nest sites on average 2.5 times further than the males. Nestling mass predicted future recruitment probability, and the mean nestling body mass of recruits was higher than the mean body mass of their non-recruited siblings. A significantly larger than expected number of recruits originated from first broods, reflecting that the timing of Barn Swallow breeding is an important factor for future recruitment. Neither nest type nor brood type affected natal dispersal. Barn Swallows raised in artificial nests were recruited more than birds raised in natural nests. Conclusion Natal dispersal of Barn Swallows in urban habitats was sex-biased, with females dispersing further than males. A Barn Swallow nestling raised early in the season (1st broods), in a clean artificial nest, and with good competitive skills for food, had a high probability of survival and local recruitment. For a declining passerine species, such as the Barn Swallow, artificial nests may be a possible conservation option in urban habitats.

Heterochiasmy and Sexual Dimorphism: The Case of the Barn Swallow (Hirundo rustica, Hirundinidae, Aves).

Heterochiasmy, a sex-based difference in recombination rate, has been detected in many species of animals and plants. Several hypotheses about evolutionary causes of heterochiasmy were proposed. However, there is a shortage of empirical data. In this paper, we compared recombination related traits in females and males of the barn swallow Hirundo rustica (Linnaeus, 1758), the species under strong sexual selection, with those in the pale martin Riparia diluta (Sharpe and Wyatt, 1893), a related and ecologically similar species with the same karyotype (2N = 78), but without obvious sexual dimorphism. Recombination traits were examined in pachytene chromosome spreads prepared from spermatocytes and oocytes. Synaptonemal complexes and mature recombination nodules were visualized with antibodies to SYCP3 and MLH1 proteins, correspondingly. Recombination rate was significantly higher (p = 0.0001) in barn swallow females (55.6 ± 6.3 recombination nodules per autosomal genome), caused by the higher number of nodules at the macrochromosomes, than in males (49.0 ± 4.5). They also showed more even distribution of recombination nodules along the macrochromosomes. At the same time, in the pale martin, sexual differences in recombination rate and distributions were rather small. We speculate that an elevated recombination rate in the female barn swallows might have evolved as a compensatory reaction to runaway sexual selection in males.

Testing the utility of condition indices in nestling swallows: a quantitative magnetic resonance approach

Nutritional condition is a key factor influencing the survival of migratory birds, and condition indices derived from morphometric measurements are commonly used to assess nutrient and energy stores. The performance and utility of condition indices used to examine energetics of growing juvenile birds remain uncertain. Recently, quantitative magnetic resonance (QMR) has been used to provide a non-invasive and non-lethal way to obtain measures of body composition. We calculated three widely used body condition indices using both wing length and tarsus length for nestling Barn Swallows Hirundo rustica erythrogaster at two ages (Day 8 and 15) and compared them to relative fat and lean mass calculated using QMR measurements. Additionally, we used QMR to develop multiple regression formulas to predict nestling fat mass, lean mass, and fat-free lean body mass (LBM) from easily obtainable body metrics. In Day 8 birds, variation in both relative fat mass and relative lean mass were adequately explained by total body mass alone, but this relationship was strongest for lean mass. Almost every condition index evaluated failed to explain variation in relative fat or lean mass in Day 15 birds. While our best multiple regression formulas for predicting fat mass and LBM had low predictive power, our formulas for predicting lean mass were precise (R2 > 90%) in both ages, providing a method to estimate the lean mass of nestlings from more readily obtainable metrics. Estimates of fat mass calculated from LBM and total body mass showed poor precision (R2 ≤ 30%).

Barn Swallows Hirundo rustica in Peninsular Malaysia: urban winter roost counts after 50 years, and dietary segregation from house-farmed swiftlets Aerodramus sp.

Barn Swallows Hirundo rustica in Peninsular Malaysia: urban winter roost counts after 50 years, and dietary segregation from house-farmed swiftlets Aerodramus sp.

Contrasting sensitivity of nestling and fledgling Barn Swallow Hirundo rustica body mass to local weather conditions

Local weather can influence the growth and development of young birds either indirectly, by modifying prey availability, or directly, by affecting energetic trade‐offs. Such effects can have lasting implications for life history traits, but the nature of these effets may vary with the developmental stage of the birds, and over timescales from days to weeks. We examined the interactive effects of temperature, rainfall and wind speed on the mass of nestling and fledgling Barn Swallows Hirundo rustica both on the day of capture and averaging weather across the time since hatching. At the daily timescale, nestling mass was negatively correlated with temperature, but the strength of this association depended on the level of rainfall and wind speed; nestlings were typically heavier on dry or windy days, and the negative effect of temperature was strongest under calm or wet conditions. At the early lifetime timescale (i.e. from hatching to pre‐fledging), nestling mass was negatively correlated with temperature at low wind speed. Fledgling body mass was less sensitive to weather; the only weather effect evident was a negative correlation with temperature at the daily scale under high rainfall that became slightly positive under low rainfall. These changes are consistent with weather effects on the availability and distribution of insects within the landscape (e.g. causing high concentrations of flying insects) and with the effects of weather variation on nest microclimate. These results together demonstrate the impacts of weather on chick growth, over immediate (daily) and longer term (nestling/fledgling lifetime) timescales. This shows that sensitivity to local weather conditions varies across the early lifetime of young birds (nestling–fledgling stages) and illustrates the mechanisms by which larger scale (climate) variations influence the body condition of individuals.

Integrating stable isotopes, parasite, and ring-reencounter data to quantify migratory connectivity-A case study with Barn Swallows breeding in Switzerland, Germany, Sweden, and Finland.

Ecosystems around the world are connected by seasonal migration. The migrant animals themselves are influenced by migratory connectivity through effects on the individual and the population level. Measuring migratory connectivity is notoriously difficult due to the simple requirement of data conveying information about the nonbreeding distribution of many individuals from several breeding populations. Explicit integration of data derived from different methods increases the precision and the reliability of parameter estimates.We combine ring‐reencounter, stable isotope, and blood parasite data of Barn Swallows Hirundo rustica in a single integrated model to estimate migratory connectivity for three large scale breeding populations across a latitudinal gradient from Central Europe to Scandinavia. To this end, we integrated a non‐Markovian multistate mark‐recovery model for the ring‐reencounter data with normal and binomial mixture models for the stable isotope and parasite data.The integration of different data sources within a mark‐recapture modeling framework enables the most precise quantification of migratory connectivity on the given broad spatial scale. The results show that northern‐breeding populations and Southern Africa as well as southern‐breeding populations and Western–Central Africa are more strongly connected through Barn Swallow migration than central European breeding populations with any of the African wintering areas. The nonbreeding distribution of Barn Swallows from central European breeding populations seems to be a mixture of those populations breeding further north and south, indicating a migratory divide.

Short Communication: Roosting behavior of Wintering Barn Swallow (Hirundo rustica) in Peninsular Malaysia

Abstract. Ismail NA, Jufri ABAK, Daud UNS, Nor SM, Mansor MS. 2020. Short Communication: Roosting behavior of Wintering Barn Swallow (Hirundo rustica) in Peninsular Malaysia. Biodiversitas 21: 661-665. The East Asian Barn Swallow Hirundo rustica gutturalis primarily breeds in China, Japan, and Korea, typically migrates to Southeast Asia during winter, including Malaysia. To date, knowledge regarding population of Barn Swallow are limited to their breeding grounds and other subspecies (e.g., European Barn Swallow Hirundo rustica rustica). A previous study on Barn Swallow wintering in Malaysia was conducted approximately 50 years ago and mainly focused on population dynamics. The objective of the present study was to investigate the roosting behavior of wintering Barn Swallows in a major roosting site, Bentong, central Peninsular Malaysia, from October 2018 to March 2019. Scan sampling at 5-min intervals was used to examine the roosting behavior of the swallows perching on service wires (i.e., electricity and telephone wires). We found that the swallows began to roost an average of 10 minutes after sunset and slept 55 minutes later. However, cloudy and rainy weather significantly affects swallow roosting period, leading them to perch earlier, 5 minutes before sunset. The pattern of roosting behavior was somewhat similar throughout the migration season, except in the early migration season (October), which was likely inconsistent due to their early adaptation to the town environment. Behavioral scan sampling revealed that swallows spend most of the time motionless, followed by preening. However, anthropogenic disturbances disrupt their behavior and sleep time. We also noted that this communally roosting bird behaved gregariously on wires, particularly at sites illuminated by light, which is likely an anti-predator mechanism.

Experimental tail shortening affects feeding rate depending on original tail length in female barn swallows Hirundo rustica gutturalis

Long tail feathers of the barn swallow Hirundo rustica are a classic example of an intersexually selected trait, but previous aerodynamic analyses indicate that the tail feather is only 10–12 mm longer than the aerodynamic optimum even in the nominate subspecies with long tails. Here, by experimentally shortening female tail length, we studied the feeding cost of long tail feathers in Japanese barn swallows, Hirundo rustica gutturalis, which have ca. 10 mm shorter tails than the nominate subspecies. Female feeding rate was explained by the interaction between treatment and original female tail length: feeding rate decreased with decreasing original female tail length in control, but not in tail-shortened females. Because the interaction term was far from significant in the analysis of female incubation investment, the observed pattern would be specific to feeding rate, which is greatly affected by the aerodynamic properties associated with tail length. Differential allocation of paternal feeding investment was not observed in the current data set. Long tails would be costly at least in short-tailed females, supporting differential costs of ornamentation as predicted by sexual selection theory. Female outermost tail feathers are costly ornamentation in short-tailed Japanese barn swallows.

Age-dependent carry-over effects in a long-distance migratory bird

Migratory birds usually respond to climate change by modifying breeding and/or wintering areas, as well as by reproducing earlier. In addition, changes in winter habitat use or breeding phenology could have important carry-over effects on subsequent breeding success. Here, we studied age- and sex-dependent carry-over effects from wintering to the breeding stage of a small aerial insectivorous long-distance migratory bird, the barn swallows (Hirundo rustica) breeding in Denmark during 1984–2013. First, we used stable isotope analyses combined with ringing recoveries to identify wintering areas. Second, we found that environmental conditions as inferred by Normalized Difference Vegetation Index (NDVI) have improved at the wintering grounds. Third, we used confirmatory path analysis to quantify the indirect effect of winter conditions on subsequent breeding success. Males delayed onset of breeding and raised fewer fledglings in the first brood when ecological conditions during the previous winter improved. This response was age dependent, since yearlings did not respond to this environmental cue but the response was increasingly stronger as males aged. Females showed a similar response to winter conditions, although not statistically significant. These results highlight the importance of studying carry-over effects within the context of climate change, especially in relation to age of individuals.

Individual condition, but not fledging phenology, carries over to affect post‐fledging survival in a Neotropical migratory songbird

Migratory animals face severe time and energy constraints during their annual cycle. These constraints may be exacerbated in young animals by conditions experienced during development that can affect both phenotype and phenology. For young migratory songbirds, the period between fledging and autumn migration, the post‐fledging period, is believed to represent a time of intense selective pressure. However, there has yet to be a study that has assessed post‐fledging survival for the entirety of the post‐fledging period, probably due to the challenge of following juveniles as they move broadly across the landscape (tens to hundreds of kilometres). To overcome this challenge, we used an automated radiotelemetry array spanning 60 000 km2 in southern Ontario, Canada, and miniature digital radiotelemetry tags to track 216 juvenile Barn Swallows Hirundo rustica continuously from fledging to migration. We hypothesized that young that fledged in better condition and earlier in the breeding season would have higher survival relative to birds fledging in poorer condition, because they have more energy to deal with resource constraints, and that early‐fledging birds would depart on migration earlier than late‐fledging birds because there is probably a fixed period of time required post‐fledging to prepare for migration. We found that average cumulative apparent survival was 42% and that condition in the nest was a strong positive predictor of post‐fledging apparent survival. We also found that birds that fledged earlier in the season departed on migration earlier in the autumn relative to late‐fledging birds. Contrary to our prediction, average apparent survival was equal for early‐ and late‐fledging birds. Our results suggest that factors during development that promote better nestling condition are critical for predicting future apparent survival prior to migration. Differences in annual apparent survival between early‐ and late‐fledging songbirds, as commonly observed, may be driven by events occurring at later stages of the annual cycle.

Barn Swallow Nest Predation by a Recent Urban Invader, the Taiwan Whistling Thrush - Implications for the Evolution of Urban Avian Communities.

Urban areas become a new habitat for an increasing number of species as they gradually adapt to the expanding, human-associated environment. The barn swallow (Hirundo rustica) has constructed nests on human buildings that provide good protection against bad weather and predators over centuries. In contrast, the Taiwan whistling thrush (Myophonus insularis) is one of new urban-invading species. The interactions between old and new urban avian species can determine the structure of this growing avian community. Here we report the first case of Taiwan whistling thrushes' predation on other birds in an urban area. Taiwan whistling thrushes were observed to eat all barn swallows' chicks and eggs on one street within one week and thus dramatically reduced their reproductive success, even severer than did a typhoon. The newly evolving predation behavior of Taiwan whistling thrushes could threaten the survival of barn swallows. If the latter cannot conquer the new challenge, the nesting ground may become an ecological trap to them driving population extirpation. This reported case implies that urbanization could intensify the interactions, such as predation or competition, between old and new urban species, leading to their population decline or growth and thus community dynamics of urban wildlife.

Representing migration routes from re-encounter data: a new method applied to ring recoveries of Barn Swallows (Hirundo rustica) in Europe

Bird ringing was established more than a century ago to gather information on bird movements. Since then, ornithologists have systematically collected huge databases of records of birds ringed and subsequently re-encountered, but, to date, there have been few quantitative attempts to identify migratory routes from ringing data. Here, we develop a novel, quantitative method for describing migration routes using ringing data and we applied it to a dataset of 72,827 ring recoveries of the Barn Swallow (Hirundo rustica) through western and central Europe from the EURING and SAFRING databanks spanning 1908–2011. We considered movements of 332 individuals during spring migration and 1509 during autumn migration. The results indicate that, in spring, Barn Swallows enter western Europe through Gibraltar or by crossing the Mediterranean Sea through the Balearic Islands, Sardinia, and the Italian peninsula. They then spread over a wide front. In northern France, Belgium and the Netherlands routes diverge, pointing toward either the British Isles or Denmark and Scandinavia. Autumn migration routes are similar to those in spring. The general migration pattern that emerged from the analyses was consistent with previous descriptions of migratory movements of this well-known species. However, this analysis also revealed some previously undocumented migration patterns. For instance, in spring, some migrants moved from the Balearic Islands to Corsica and Italy, thus making a rather long eastward crossing of the Mediterranean Sea. In autumn, some migrants moved from the Balkan Peninsula westwards toward Italy. Analyses restricted to recoveries within the same spring or the same autumn and to birds found dead showed similar patterns. Our procedure was, therefore, able to identify migration patterns over a large geographical area, and may be extended to those species for which large datasets of ring recoveries or sight-resight data are available.

Bird ringing report for Slovenia in 2017 and short overview of colour ringing in the period of 2012–2017

Abstract In 2017, the Slovenian bird ringing scheme concluded 90 years of continuous ringing in the country. In 2017, we collected data on 176 bird species. We ringed 79,886 birds of 164 species, recorded 177 recoveries of birds ringed in Slovenia and found abroad, 295 foreign recoveries in Slovenia and 2,209 local recoveries. The most ringed species were the Blackcap Sylvia atricapilla and Great Tit Parus major and, among pulli in the nest, the Great Tit, White Stork Ciconia ciconia and Barn Swallow Hirundo rustica. In 2017, 12 colour ringing schemes were active in Slovenia. In the 2012-2017 period, the number of recoveries of birds ringed in Slovenia and found abroad increased significantly due to colour ringing, especially regarding the waterbirds. With colour ringing, the likelihood of recoveries is considerably greater (75.20 ± 91.36 recoveries per 100 ringed birds) than with metal ringing only (0.11 ± 0.08 recoveries per 100 ringed birds). Among local recoveries, the most frequent were the Mute Swans Cygnus olor and Common Terns Sterna hirundo, and among foreign recoveries the Black-headed Gulls Chroicocephalus ridibundus predominated. In 2017, the first Broad-billed Sandpiper Calidris falcinellus was ringed in Slovenia (Sečovlje salinas), and additional three rare species were ringed as well: the Yellow-browed Warbler Phylloscopus inornatus (Ljubljansko barje), Paddyfield Warbler Acrocephalus agricola (Ljubljansko barje) and Little Bunting Emberiza pusilla (Šentrupert).

Reproductive success related to uropygial gland volume varies with abundance of conspecifics in barn swallows Hirundo rustica

Pathogens have negative effects on the fitness of their hosts, reducing survival and/or decreasing their reproductive success. To cope with pathogen challenge, animals have developed a variety of defensive traits to evade parasite infection and minimize their detrimental effects. Uropygial gland secretion has been proposed to have antimicrobial and antifungal properties, which may potentially influence bird fitness. However, whether uropygial gland secretion may affect the breeding success of birds remains unknown. Here, we explore whether the relationship between uropygial gland volume and reproductive success could be determined by the abundance of conspecific barn swallows (Hirundo rustica), a small colonial migratory hirundine. Because a larger number of swallows nesting within the same building may boost abundance and transmission of pathogens, we predicted that the anti-pathogen properties of uropygial gland secretion may enhance bird reproductive success in environments with high density of conspecifics. We showed that barn swallows with larger uropygial glands had higher breeding success (greater total number of fledglings reared) when living in environments with higher abundance of conspecifics. In contrast, barn swallows with larger uropygial glands had lower reproductive success when breeding in environments with lower abundance of conspecifics. Furthermore, we found that the same individuals did not modify uropygial glands in response to different pathogen pressure experienced across consecutive years. These outcomes suggest that benefits of uropygial secretion are host density dependent, thus consistent with this being a heritable trait that has evolved as a consequence of divergent selection imposed by pathogens. To face pathogen challenges, animals have evolved a broad range of barriers and defense mechanisms to avoid parasite infection and/or to minimize negative effects. Uropygial gland secretion has been proposed to have antimicrobial and antifungal properties, but also act as a defensive mechanism against malaria infection. However, whether uropygial gland secretions may affect the reproductive success of birds remains poorly studied. In this study, we explore, for the first time, whether the relationship between uropygial gland volume and reproductive success could be determined by the abundance of conspecifics. We found that barn swallows with larger uropygial glands had higher breeding success when living in environments with higher abundance of conspecifics. Because a larger number of swallows nesting within the same building may boost abundance and transmission of pathogens, this novel outcome is consistent with a heritable trait that has evolved as a consequence of divergent selection imposed by pathogens.

Wintering Areas, Migratory Connectivity and Habitat Fidelity of Three Declining Nearctic- Neotropical Migrant Swallows

Abstract Conservation efforts directed at population declines for migratory animals must consider threats occurring at different stages often separated by vast distances. Furthermore, connectivity between populations and fidelity of individuals to specific habitats during the annual cycle are also important considerations. Avian aerial insectivores are experiencing steep population declines in North America, and those declines may be driven, in part, by conditions on the wintering grounds. Here, using geolocators (2 species; 4 individuals) and stable isotope (δ2H, δ13C and δ15N) measurements of feathers (3 species; 841 individuals), we identified approximate winter areas, and assessed migratory connectivity and among-year winter habitat fidelity for three aerial insectivores (Bank Swallow Riparia riparia, Barn Swallow Hirundo rustica and Cliff Swallow Petrochelidon pyrrhonota) that breed in northeastern North America. All three species of swallows are declining in this region. Our results, largely from the stable isotope analysis, suggest that these species likely winter throughout the Cerrado, La Plata Basin, and the Pampas, in South America. These most likely areas were similar among years (2013-2016) for Bank and Cliff Swallows, but varied for Barn Swallows (2014-2016). We found weak migratory connectivity for all three species, and, with one exception, weak habitat fidelity among years for individuals. For individual Barn Swallows captured in two or more years, we found high repeatability in δ13C values, suggesting some fidelity to similar habitats among years. The most likely wintering areas for these species coincide with large areas of South America experiencing high rates of land-use change.

Birds respond similarly to taxidermic models and live cuckoos Cuculus canorus

Stuffed birds are widely used in research for identifying effects of predators and nest parasites on bird behaviour, studying levels of aggression and the size of territories. However, the fact that these models do not move or vocalize may question the results of such studies and open them to criticism. One solution would be to determine how the results of research using stuffed dummies correlate with the response of wild animals to enemies under the same environmental conditions. In a first attempt, we examined the correlation between the intensity of mobbing of a dummy cuckoo Cuculus canorus and interactions with live cuckoos in the field during the breeding season in western Poland. A total of 39 bird species mobbed cuckoo dummies; all 39 were found to attack live cuckoos, while 24 species (61.5%) did so during experiments using a dummy. The number of individual birds involved in mobbing a dummy was positively correlated with the number of individuals attacking real cuckoos in the same areas, even when the most commonly mobbing species, the barn swallow Hirundo rustica, was excluded from the analyses. However, we did not find significant differences in frequency of mobbing behaviour depending on cuckoo behaviour described as flight or sitting, or calling rather than remaining quiet. Therefore, we conclude that the use of a dummy for studying mobbing of hosts and non-hosts of the cuckoo provide results that are similar to those made in response to the behaviour of live hosts.

Migratory connectivity of barn swallows in South Africa to their Palaearctic breeding grounds

AbstractAimTo demonstrate that the population of barn swallow Hirundo rustica in South Africa in the austral summer is not a pan‐mixture of birds from their vast Palaearctic breeding range and to estimate proportions of barn swallows in four South African regions migrating to three breeding ground zones.LocationSouth Africa and Eurasia.MethodsWe analysed citizen science barn swallow ringing records, obtained between 1954 and 2011 in South Africa, and their recoveries made in Eurasia. We used the “division coefficient” method to model the spatial variability of the recovery process and to estimate proportions of barn swallows ringed in four regions of South Africa (KwaZulu‐Natal, Gauteng, eastern part of Northern Cape and the Western Cape) migrating to three zones in the Eurasian breeding grounds: western (west of 10°E), central (10°–60°E) and eastern (east of 60°E).ResultsThe percentages of barn swallows migrating from KwaZulu‐Natal to the eastern and central Palaearctic zones were estimated at 54.0% and 46.0%, respectively. The percentages from Gauteng to the central and western zones were 80.5% and 15.7%, from the Northern Cape to the central and western zones were 43.7% and 56.3% and from the Western Cape to the eastern, central and western zones were 30.8%, 35.4%, 33.8%. The estimate of the observer process suggested that reencounter rates per 10,000 swallows ringed increased from east to west: 32 reencounters per 10,000 in the eastern zone, 36 in the central zone and 50 in the western zone.Main conclusionsThese results provide the first quantitative estimates of the composition of barn swallow populations in four regions of South Africa, relative to their Palaearctic breeding zones.

Use of field margins managed under an agri-environment scheme by foraging Barn Swallows Hirundo rustica

ABSTRACTCapsule: Barn Swallows Hirundo rustica were more likely to forage along arable field margins that were enhanced with wildflowers or legumes than control grass margins.Aims: To determine if foraging Barn Swallows displayed preferences for specific arable field boundary habitats (grass margins versus floristically enhanced margins) that were managed as part of an agri-environment scheme. We also aim to determine how Barn Swallow food abundance related to these habitats.Methods: Two foraging activity surveys took place on all grass and floristically enhanced margins (n = 56) present within the 600 m foraging range of seven Barn Swallow colonies during June and July 2016. Margin habitat use was measured by recording the presence/absence of foraging individuals during surveys, the total number of individuals and by calculating an index of foraging activity. Habitat information relating to adjacent boundary type, transect crop type and neighbouring crop type were also recorded.Results: Foraging Barn Swallows were significantly more likely to be recorded when survey transects included a floristically enhanced margin, but there was no significant impact of floristically enhanced margins on the total number of individuals recorded or on the index of foraging activity. Foraging activity was higher along grass verges and hedgerows when compared to treelines and was positively related to length weighted Diptera abundance (a measure of food biomass).Conclusion: Our results suggest that there may be a role for floristically enhanced margins in the conservation of Barn Swallows on arable farmland. More research, however, is needed to determine whether invertebrate-rich agri-environment scheme habitats can influence colony size or improve the breeding success of this species.

Sexual Selection Mechanisms for Male Plumage Ornaments in Japanese Barn Swallows

The Barn Swallow Hirundo rustica is a model species for studying sexual selection. After its long tail was shown to be the target of female mate choice, its plumage characteristics, including the red throat patch and the size of white tail spots in addition to tail length, have attracted the attention of many researchers. Although there have been several reviews of sexual selection in this species, these reviews have focused mostly on general patterns of sexual selection within and among subspecies, rather than on the functional differences between plumage characteristics in sexual selection. Here, I review mechanisms of sexual selection for male plumage ornaments in Japanese Barn Swallows H. r. gutturalis. In the last decade, studies of sexual selection in Japanese Barn Swallows have focussed on tail length, the size of the white tail spots, and the size and coloration of red throat patches. Each ornamental trait appears to be involved in different sexual selection mechanisms: the size of the white tail spots is important for several mechanisms of intersexual selection, including the Darwin-Fisher mechanism and differential allocation, whereas throat coloration may be intra-sexually selected, at least in part. The size of the throat patch, in contrast, is the target of an intersexual selection mechanism, differential access, indicating a partially independent evolution of the two components of the red throat patch. Multiple mechanisms of sexual selection would explain the multiple ornaments and their geographical variation, and even the probability of speciation and extinction.