Male Barn Swallows Tolerate Nestling-Like Courtship Calls of Rival Males

Animals often exhibit conspicuous, and sometimes curious, courtship traits, such as nestling-like courtship display in birds, though modern studies of nestling-like courtship display (and calls) are virtually lacking. An exception is previous experiments on the barn swallow Hirundo rustica, demonstrating that females are equally attracted to playback of two structurally similar calls, nestling-like male courtship calls and nestling food-begging calls. The experiments support the sensory trap hypothesis, i.e., that male signals mimic nestling stimuli to exploit female parental care for nestlings. However, female attraction might not be the sole function of nestling-like traits, and males might also have a sensory bias toward nestling-like traits, in which males would be less aggressive toward characteristics typical of immature individuals. Here, I conducted playback experiments to study the function of nestling-like male courtship calls in the context of male–male interactions. Playback of male courtship songs induced frequent approaches by neighbouring males, while nestling-like male courtship calls or nestling food-begging calls induced fewer approaches, though male responses to the latter two vocalisations increased when approaching the nestling period. The observed pattern indicates that, by mimicking immature individuals, males attract intended signal receivers (i.e., females) while avoiding interference from eavesdroppers (i.e., neighbouring males). This unique function can explain why species with parental care exhibit immature-like behaviour.

Population trends of passage and wintering barn swallows (Hirundo Rustica) in Peninsular Malaysia

In Peninsular Malaysia, passage and wintering Barn Swallows (Hirundo rustica) often congregate at nocturnal roosts in towns. As a Holarctic migratory species, it is at risk of population collapse. Despite extensive research, little is known about this species in its wintering grounds, especially in the tropics. This study aimed to determine how climate change influences the population growth of this species across a geographical area over a decade, from 2009 to 2019. A species distribution model was constructed using data obtained from the eBird database – a citizen science project – of records from diverse locations. We used the Kernel Density tool in ArcGIS to describe Barn Swallow density and expansion pattern across Peninsular Malaysia. We demonstrate that the Barn Swallow’s population has fallen by about 27.1% over the last decade. In 2009, the species was dispersed in two distinct areas: Perlis to Pulau Pinang; and the Pahang region bordering Selangor and Negeri Sembilan; in addition, some individuals chose to winter in south-eastern Johor. Within ten years, the flock has descended from Perlis to the northwest corner of Perak, while the vast wintering area in Pahang has decreased and stretched down to Melaka and Johor. The differences in Barn Swallow numbers and distribution patterns observed in this study could be a result of climate and land use changes which have caused this species to spread to parts of other wintering regions, altering the arrival and departure times of migration, thereby interfering with its breeding season.

Highly Conservative Pattern of Sex Chromosome Synapsis and Recombination in Neognathae Birds

We analyzed the synapsis and recombination between Z and W chromosomes in the oocytes of nine neognath species: domestic chicken Gallus gallus domesticus, grey goose Anser anser, black tern Chlidonias niger, common tern Sterna hirundo, pale martin Riparia diluta, barn swallow Hirundo rustica, European pied flycatcher Ficedula hypoleuca, great tit Parus major and white wagtail Motacilla alba using immunolocalization of SYCP3, the main protein of the lateral elements of the synaptonemal complex, and MLH1, the mismatch repair protein marking mature recombination nodules. In all species examined, homologous synapsis occurs in a short region of variable size at the ends of Z and W chromosomes, where a single recombination nodule is located. The remaining parts of the sex chromosomes undergo synaptic adjustment and synapse non-homologously. In 25% of ZW bivalents of white wagtail, synapsis and recombination also occur at the secondary pairing region, which probably resulted from autosome−sex chromosome translocation. Using FISH with a paint probe specific to the germline-restricted chromosome (GRC) of the pale martin on the oocytes of the pale martin, barn swallow and great tit, we showed that both maternally inherited songbird chromosomes (GRC and W) share common sequences.

Seasonal effects of Land cover changes on ecological of migratory birds in Al-Hammar Marsh, southern Iraq

Al-Hammar Marsh in Iraq stands out for hosting the largest concentrations of coastal migratory birds along the migration path between the Arabian Gulf and the Mediterranean Sea. Despite this importance, there is no complete review of the dynamics of these birds. In this study, we collected and analyzed the results of six species of migratory birds (Mallard duck, Graylag goose, White pelican, Barn swallow, Common gull, White stork) in the Region, in addition to the results of the land cover in October of 2000 to 2020, The results show the presence across the past two decades of a change in the population makeup of migratory birds. Complete numbers of migratory birds indicated a decline in the residual types between 2000 and 2020. The disproportion among numbers was also too large for trends to be observed. The region also showed a decrease in the areas of vegetation cover during the study period was equal to 5.0%, 3.5%, and 15.6%, And an increase in the areas of water bodies during the study period was equal to 7.8%, 21.0%, and 62.6%, respectively, Finally, A multivariate analysis suggests a general decline in types that depend on the Wetland for feeding and breeding an in the sublittoral and the offshore zones. Use satellite data can be used for monitoring several variables such as water bodies, vegetation cover, Climate factors that influence the activity of Migratory birds.

Trace elements fingerprint of feathers differs between breeding and non-breeding areas in an Afro-Palearctic migratory bird, the barn swallow (Hirundo rustica)

Trace elements are widespread contaminants that can potentially threaten ecosystems and human health. Considering their distribution and toxicity, monitoring their presence in animals represents a priority in environmental risk assessment. Migratory birds have been suggested to be useful biomonitors for trace elements because they can provide information on contaminants even from remote areas that they may exploit during their life cycle. The aim of this study was to analyse the contamination fingerprint of trace elements of African non-breeding staging grounds and European breeding areas in a long-distance migratory passerine bird, the barn swallow (Hirundo rustica). We collected feathers grown in the African non-breeding grounds and those grown in the breeding areas of Northern Italy and measured the levels of 12 trace elements (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn) by DRC-ICP-MS. Multivariate analysis showed that elemental profiles of feathers grown in African non-breeding areas and in the Italian breeding ones clearly differed, with feathers grown in Africa showing higher concentrations of Al, Cu, Fe, Mn and Ni, but lower concentrations of As, Se and Zn, compared to those grown in Italy. In addition, levels of trace elements were age-dependent, with higher levels in older individuals than in younger ones. Our results add to the growing evidence that feathers of long-distance migratory birds are useful tools to monitor trace elements contamination profiles across continents.