Fading feathers: documenting the progressive greying House Sparrow (Passer domesticus) from Karnataka, India

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Testosterone has recently been proposed as a link between male quality and health and the expression of sexual traits. We investigated the relationship between testosterone and measures of the individual condition and health of males in a natural population of house finches (Carpodacus mexicanus). We also conducted a captive experiment in order to test for the effects of testosterone on resistance to coccidia, which is a common parasite of house finches. Free-living males in better condition had higher testosterone levels and lower corticosterone levels than free-living males in poor condition. In our captive experiment, increased testosterone accelerated the rate of coccidial infection as compared with sham-implanted or gonadectomized males. Although the differences were not significant, free-living males infected with coccidia had lower levels of testosterone and higher levels of corticosterone than males that were not infected. Thus, experimentally elevating testosterone levels in captive males resulted in a higher percentage of infected males, while free-living males with coccidial infection had low testosterone levels. This apparent discrepancy between captive and free-living males in the association of testosterone and disease may be explained by the condition dependence of testosterone. These results suggest that the testosterone-dependent sexual traits reliably indicate male overall condition and health and, thus, females could benefit from assessing potential mates based on these traits.

House sparrows (Passer domesticus) are a hugely successful anthrodependent species; occurring on nearly every continent. Yet, despite their ubiquity and familiarity to humans, surprisingly little is known about their origins. We sought to investigate the evolutionary history of the house sparrow and identify the processes involved in its transition to a human-commensal niche. We used a whole genome resequencing dataset of 120 individuals from three Eurasian species, including three populations of Bactrianus sparrows, a non-commensal, divergent house sparrow lineage occurring in the Near East. Coalescent modelling supports a split between house and Bactrianus sparrow 11 Kya and an expansion in the house sparrow at 6 Kya, consistent with the spread of agriculture following the Neolithic revolution. Commensal house sparrows therefore likely moved into Europe with the spread of agriculture following this period. Using the Bactrianus sparrow as a proxy for a pre-commensal, ancestral house population, we performed a comparative genome scan to identify genes potentially involved with adaptation to an anthropogenic niche. We identified potential signatures of recent, positive selection in the genome of the commensal house sparrow that are absent in Bactrianus populations. The strongest selected region encompasses two major candidate genes; COL11A-which regulates craniofacial and skull development and AMY2A, part of the amylase gene family which has previously been linked to adaptation to high-starch diets in humans and dogs. Our work examines human-commensalism in an evolutionary framework, identifies genomic regions likely involved in rapid adaptation to this new niche and ties the evolution of this species to the development of modern human civilization.

The House Sparrow Passer domesticus is traditionally associated with human habitation. However, the species has undergone dramatic declines in many urban areas in north-western Europe. There are many theories as to why this decline has occurred, but the lack of data on House Sparrow numbers prior to their decline has hampered efforts to investigate these theories in detail. This review summarises the demographic changes in urban House Sparrow populations since the 1970s, and considers evidence that the current distribution of House Sparrows may reflect changes in urban habitats caused by socioeconomic change. Evidence is mounting that, within urban landscapes, House Sparrows appear to be more prevalent in areas with a relatively low human socioeconomic status. Here, we present evidence to suggest that House Sparrows may have disappeared predominantly from more affluent areas, and that these areas are more likely to have undergone changes to habitat structure. We also show how these changes in habitat could influence House Sparrow populations via impacts upon nesting success, foraging and predation risk.

Following extensive renovation of urban areas of central Israel, and in the framework of a research project of supplying nest-boxes for urban breeding birds, especially Common Swifts Apus apus, we documented interspecific nest destruction by House Sparrows Passer domesticus. In two separate incidents the House Sparrows entered the nest chamber of the swifts and removed the eggs by puncturing them. In one, the incident occurred early enough in the breeding season and allowed the Common Swift pair to renest and successfully fledge two young.

Testicular Response of the House Sparrow, Passer Domesticus, to Short Photoperiods and Low Intensities

Gene transfer may occur following hybridization between closely related species if hybrids are viable and able to breed with individuals of one or both of the parental species. House (Passer domesticus) and tree sparrows (P. montanus) occasionally hybridize and produce viable offspring. Previously, we concluded that male tree × house sparrow hybrids are most probably fertile based on the observation of a male F1 hybrid feeding the nestlings with a female house sparrow in two consecutive clutches. However, recent DNA analyses based on blood samples revealed that all nestlings (4) in the first clutch were sired by a neighbouring house sparrow male, whereas nestlings in the second clutch (2) were not blood sampled and most probably died before fledging. This indicates that extensive extra-pair fertilization confounded our previous conclusion, and indicates that social partnership and attending behaviour can be imprecise measures of paternity.

The House Sparrow Passer domesticus is recognised as one of the commonest avian invasive species globally, with its occurrence associated with human existence. However, relatively little on population sizes of this species in rural landscapes has been documented. The study on House Sparrows was conducted in three areas in a rural landscape of Limpopo province, South Africa where it is an invasive, to 1) determine population numbers of the House Sparrow between the years 2014 and 2016, and 2) investigate the interaction between the number of House Sparrows and the number of their active nests. The House Sparrow population numbers showed no significant differences between 2014, 2015 and 2016. The House Sparrow numbers were influenced by the number of active nests in 2014 and 2016. The current study showed that the presence of House Sparrows was not affected by the house type they roosted in, and the number of active nests was not influenced by the house types available in each area. The results also showed that the House Sparrow occurs across a rural landscape with variation in numbers across seasons. The evidence reported provides significant insight into how invasive House Sparrows are well established in rural landscapes around human habitation, and it is recommended that this should be incorporated into the management of such alien invasive birds.

Urbanization affects the ecology of wildlife diseases and although it has been suggested that there are lower risks of infection in urban areas, there have been no experiments to support this conclusion. We assessed haemosporidian prevalence and intensity in House Sparrows Passer domesticus using field and experimental data under contrasting conditions (i.e. urban vs. non‐urban). For experimental data, we kept 32 male House Sparrows in captivity as a proxy of stress, and for field data we sampled 49 House Sparrows (17 females). We made use of microscopy to determine the relative intensity and used the polymerase chain reaction to estimate infection prevalence. We obtained total leucocyte counts, leucocyte differentials, heterophil/lymphocyte ratio (H/L) as a measure of stress, and the Polychromatic Index as a measure of physiological condition (erythropoiesis). We identified a total of 10 haemosporidian lineages. For field samples (both males and females), we found a significantly higher prevalence of infection in non‐urban House Sparrows than in urban ones. Under experimental conditions, non‐urban House Sparrows showed a higher prevalence than urban ones both before and after captivity, with a significant increase in parasite intensity. The number of infected birds increased after captivity for both urban (~ 32%) and non‐urban House Sparrows (~ 19%), indicating either a recrudescence of chronic and relapses of latent infections or the appearance of infections that had been acquired earlier. The H/L ratio was significantly higher for non‐urban than for urban male House Sparrows before captivity. No difference in H/L was found for urban House Sparrows before and after captivity, indicating tolerance to city stressors. Our results showed a significant decrease in H/L for non‐urban birds after captivity, suggesting higher stress in the non‐urban agricultural environment. Haemosporidian infections were not associated with the H/L ratio. Our study provides evidence that highly urbanized areas within cities represent lower haemosporidian infection risks than do non‐urban areas for House Sparrows.

The aim of this study was the evaluation of environmental pollution with heavy metals such as Lead and Nickel on the living organisms in industrial areas, using the blood of House sparrow (Passer domesticus) as a bio-indicator of pollution by metals. For this purpose, a blood collection was performed on 32 house sparrows (Passer domesticus) males and females, which were captured in Mitrovica town (situated close to smelter “Trepqa”, closed in year 2000), Drenas town (near the Ferronickel smelter, pollution area) and in rural area (Ujmir village, not contaminated area). In blood plasma we have analysed: alkaline phosphatase (AP), plasma alanin aminotransferase (ALT), aspartat aminotransferase (AST) and total proteins (TP) in house sparrow (Passer domesticus). The results obtained indicate the different values of the enzymes activity (AP, ALT, AST) in blood sparrows between the localities studied. Higher values of AST in significant scale (p<0.001) were found in sparrows from Mitrovica and Drenas town compared with the reference site (Ujmire village). Values of enzymes ALT, AP and total proteins are different between the analyzed groups but the differences are not significant. Further studies are warranted to investigate the mechanism of susceptibility of house sparrow to environmental pollution.

Wild birds are considered reservoirs of poultry pathogens although transmission routes have not been conclusively established. Here we use camera trapping to study wild bird communities on commercial layer and red-legged partridge farms over a one-year timeframe. We also analyze direct and indirect interactions of other bird species with the house sparrow (Passer domesticus), a potential bridge host. We conducted camera trapping events between January 2018 and October 2019, in two caged layer farms, one free-range layer farm, and two red-legged partridge farms in South-Central Spain. We observed wild bird visits on all types of farms, with the significantly highest occurrence on red-legged partridge farms where food and water are more easily accessible, followed by commercial caged layer farms, and free-range chicken farms. The house sparrow (Passer domesticus) followed by spotless starlings (Sturnus unicolor) was the most encountered species on all farms, with the highest frequency in caged layer farms. On partridge farms, the house sparrow accounted for 58% of the wild bird detections, while on the free-range chicken farm, it made up 11% of the detections. Notably, the breeding season, when food and water are scarce in Mediterranean climates, saw the highest number of wild bird visits to the farms. Our findings confirm that the house sparrow, is in direct and indirect contact with layers and red-legged partridges and other wild birds independent of the type of farm. Contacts between house sparrows and other bird species were most frequent during the breeding season followed by the spring migration period. The species most frequently involved in interactions with the house sparrow belonged to the order Passeriformes. The study provides a comparative description of the composition and seasonal variations of bird communities in different types of layer/ poultry farms in Southern Spain i.e. a Mediterranean climate. It confirms the effectiveness of biosecurity measures that restrict access to feed and water. Additionally, it underscores the importance of synanthropic species, particularly the house sparrow, as potential bridge vector of avian pathogens.

As a highly successful introduced species, house sparrows (Passer domesticus) respond rapidly to their new habitats, generating phenotypic patterns across their introduced range that resemble variation in native regions. Epigenetic mechanisms likely facilitate the success of introduced house sparrows by aiding particular individuals to adjust their phenotypes plastically to novel conditions. Our objective here was to investigate patterns of DNA methylation among populations of house sparrows at a broad geographic scale that included different introduction histories: invading, established, and native. We defined the invading category as the locations with introductions less than 70 years ago and the established category as the locations with greater than 70 years since introduction. We screened DNA methylation among individuals (n = 45) by epiRADseq, expecting that variation in DNA methylation among individuals from invading populations would be higher when compared with individuals from established and native populations. Invading house sparrows had the highest variance in DNA methylation of all three groups, but established house sparrows also had higher variance than native ones. The highest number of differently methylated regions were detected between invading and native populations of house sparrow. Additionally, DNA methylation was negatively correlated to time-since introduction, which further suggests that DNA methylation had a role in the successful colonization's of house sparrows.

ABSTRACTCapsule: House Sparrows Passer domesticus in the Valencian Community, where the species is declining, were more abundant in parks and urban areas where rubbish bins are available as a source of food. In heavy traffic areas, crowded streets and high-rise building zones, the species was less abundant.Aims: To explore biotic and abiotic factors affecting the abundance of urban House Sparrows. To infer the causes that might explain the urban decline and to propose measures that might halt it and elevate population numbers.Methods: The abundance of urban House Sparrows was analysed in relation to 17 landscape variables by carrying out 181 point counts (50 urban parks/38 schools/93 streets) per season across six locations and over five seasons (breeding and non-breeding seasons) in southeast Spain. Urban parks were also described by 21 additional variables. Hierarchical partitioning analyses were used to identify favoured or avoided urban factors by birds in each season.Results: House Sparrows were most abundant in parks and other urban areas where rubbish bins were available as their foraging sites. The presence of rubbish bins, area and proximity to other parks favoured their abundance in parks. Furthermore, House Sparrows were less abundant in crowded streets, heavy traffic areas and high-rise buildings zones.Conclusion: House Sparrows were present in high abundance where they feed but were scarce in polluted, crowded and heavily built-up areas of the city. Changes in the structure of these urban habitats may underlie the documented declines across Spain. Green urban planning and management are needed to ensure heterogeneous green areas with enough vegetation coverage to provide high availability of natural food versus anthropogenic food scraps. Sufficient numbers of buildings offering nest sites and reduced air pollution might ameliorate cities adequately to support larger populations of House Sparrows.

The house sparrow (Passer domesticus) is one of the most widespread invasive bird species, with numerous and dense populations established across urban-agricultural landscapes of North America. Although this species has been widely studied to identify the traits that explain its global ubiquity, descriptions of house sparrow acoustic features across its native and introduced range are limited in the literature. We recorded male house sparrow vocalizations from 13 cities across Europe and North America to quantify the structural features of its common “chirrup” vocalization. Although the basic structure and duration were consistent across the two geographic regions, the vocalizations differed in their minimum frequencies and bandwidth. In a post hoc analysis of 140 museum specimens, we found that European house sparrows had larger bills and bodies than those in North America. Thus, we propose that these frequency shifts could be a result of synergistic interactions between morphological differences, potential differences in ambient noise, acoustic overlap with other species within the soundscape, or other acoustic features of European and North American cities. House sparrows seem to be a good model for future bioacoustics studies, given their worldwide distribution and acoustic plasticity, to test hypotheses related to urbanization traits and invasion potential.

The house sparrow (Passer domesticus) is showing population declines in many parts of Europe, with recent declines being particularly severe in urban areas. To date, relatively little is known about the species’ habitat associations within urbanized landscapes. We report here an investigation of the habitat associations of house sparrows using a survey of 1223 stratified randomly selected 500 × 500-m squares within urbanized landscapes of the UK, defined as at least 25% ‘human cover’. The densities of chirping male house sparrows and of all house sparrows were analysed separately to obtain insights into breeding habitat requirements and general habitat associations, respectively. Multi-model inference showed that residential areas (houses, flats), allotments (areas used for small-scale horticulture) and farm buildings were key predictors of house sparrow density and chirping male density. Separate analyses on landscapes of differing human cover showed similar results. Within residential areas, the increase of house sparrow density with habitat area (on a log scale) was approximately threefold greater when private gardens were present than when they were absent. The model predicted a rapid decline in house sparrow abundance when only a small area of private gardens is converted to continuous housing. Allotments and residential areas with gardens are likely to be under pressure due to increased demand for housing, specifically from the infilling of green space within urban areas. It would seem to be imperative that any action plan to protect urban house sparrow populations should include specific protection of such key habitats.