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In the intricate web of plant–animal interactions, granivore birds can play a dual antagonist–mutualist role as seed predators and dispersers. This study delves into the ecological significance of the house sparrow (Passer domesticus) as seed disperser by endozoochory. A sample of individual droppings and faecal pools were collected from a communal roost in central Spain to examine the presence of seeds. Seed viability was determined using the tetrazolium test. Our findings revealed that around 22% of the analysed droppings contained seeds, contradicting the prevalent notion of house sparrow solely as seed predator. Viability tests demonstrated that 53.9% of the defecated seeds were viable, although it varied between plant species, including those from fleshy‐fruited common fig and five species of dry‐fruited herbs. This study challenges the traditional perspectives on the ecological role of the house sparrow, and glimpses on their contribution to seed dispersal. Understanding the nuanced roles of granivore species like the house sparrow is crucial for developing holistic conservation and management strategies in urban and agricultural landscapes. Future studies are encouraged to unravel the actual role of this cosmopolitan species as disperser of a likely broad spectrum of wild, cultivated and exotic plants. [ABSTRACT FROM AUTHOR]

This study investigated cadmium in urban sparrows from various Meknes zones with differing industrial and traffic intensities, compared to a rural site. Forty sparrows from industrial regions and ten from rural were analysed post-capture. Cadmium extraction used acid mineralisation, quantified via ICP. Findings revealed higher cadmium in sparrows' kidneys from industrial zones than the rural site, with an average of 1.25 µg/g wet weight, indicating urban and industrial impacts on metal accumulation. The kidneys showed notable vulnerability to cadmium. Statistical data highlighted significant concentration differences between zones. This research emphasises the need for environmental monitoring and pollution strategies in urban areas for safeguarding health. [ABSTRACT FROM AUTHOR]

Abstract In the intricate web of plant–animal interactions, granivore birds can play a dual antagonist–mutualist role as seed predators and dispersers. This study delves into the ecological significance of the house sparrow (Passer domesticus) as seed disperser by endozoochory. A sample of individual droppings and faecal pools were collected from a communal roost in central Spain to examine the presence of seeds. Seed viability was determined using the tetrazolium test. Our findings revealed that around 22% of the analysed droppings contained seeds, contradicting the prevalent notion of house sparrow solely as seed predator. Viability tests demonstrated that 53.9% of the defecated seeds were viable, although it varied between plant species, including those from fleshy‐fruited common fig and five species of dry‐fruited herbs. This study challenges the traditional perspectives on the ecological role of the house sparrow, and glimpses on their contribution to seed dispersal. Understanding the nuanced roles of granivore species like the house sparrow is crucial for developing holistic conservation and management strategies in urban and agricultural landscapes. Future studies are encouraged to unravel the actual role of this cosmopolitan species as disperser of a likely broad spectrum of wild, cultivated and exotic plants.

Urban areas provide a constant and predictable supply of anthropogenic processed food. The House Sparrow (Passer domesticus Linnaeus, 1758), a declining urban bioindicator species, has recently been reported to have a high level of oxidative stress, with urban diet or pollutants proposed as the potential cause. In this study, we aimed to experimentally determine the effects of two urban trophic resource types (bar snack food leftovers and pet food) on sparrows' physical condition, plasma biochemical nutritional parameters, and blood oxidative status in captivity. To exclude the potential previous effect of urban pollutants, 75 House Sparrows were captured from a rural area in SE Spain and kept in outdoor aviaries. Individuals were exposed to one of three diet treatments: control diet (fruit, vegetables, poultry grain mixture), bar snack diet (ultra‐processed snacks), or cat food diet (dry pellets) for 20 days. Blood samples were collected before and after diet treatments to analyze the relative change rates of 12 variables, including physical condition, nutritional status, and oxidant–antioxidant status. A principal component analysis was run to identify gradients of variables covariation, and Generalized Linear Mixed Models were used to determine the effect of diets on each selected PC and on raw variables. The bar snack diet led to signs of anemia and malnutrition, and females tended to lose body condition. The cat food diet increased oxidative stress indicators and protein catabolism. Unbalanced urban diets can affect the body condition and nutritional physiology of House Sparrows and may also induce oxidative stress despite the absence of environmental pollution. [ABSTRACT FROM AUTHOR]

Parasites are known to be a key driving force in mate choice and are important for the expression and evolution of ornaments and behavioral traits being used. However, there is little experimental evidence on how the parasite's burden of the choosing individual is integrated into the mate-choice process and how it affects decision-making, especially in relation to parasite infestation of potential mates. Thus, the aim of our study was to determine whether female house sparrows Passer domesticus adjust their mate preference according to their own as well as the parasite load of prospective partners. To do this, we experimentally manipulated female parasite load and determined their mate preferences prior to and after parasite treatment. We manipulated the chronic coccidian parasite burden of females either by initiating the acute infection phase via re-infecting them with coccidian or by temporally reducing the parasite load of coccidia. We then measured the effect of this manipulation on mate preference by presenting females with a choice of four stimuli: three males with similar ornaments, but unmanipulated, naturally varying chronic coccidiosis levels, and an unmanipulated control female. Additionally, we recorded some males' behavior in relation to their infection status pointing toward an increased or reduced interest in mating. We found that females preferred highly infested males prior to manipulation, regardless of their own infestation level. However, after manipulation, infested females avoided highly infested males probably in response to the deterioration of their health condition by parasites. Our study suggests that mate-choice decisions are more complex when they are mediated by parasites. The implications of parasites for evolutionary theories of sexual signaling and mate choice are discussed. [ABSTRACT FROM AUTHOR]

The invasion of vector-borne diseases depends on the type of specific features of the vector and hosts at play. Within the Culex pipiens complex, differences in ecology, biology, and vector competence can influence the risk of West Nile virus (WNV) outbreaks. To determine which life-history traits affect WNV invasion into susceptible communities the most, we constructed an epidemiological Susceptible-Exposed-Infectious-Recovered model with three vector (eco)types, Culex pipiens pipiens, Cx. pip. molestus, and their hybrids, and two vertebrate hosts, birds (as amplifying hosts) and humans (as dead-end hosts). We investigated how differences in feeding preferences and transmission rates influenced WNV transmission across different habitats and two seasons (Spring versus Summer), to investigate the impact of increasing mosquitoes on the WNV transmission risk. Our results showed that vector feeding preferences and the transmission rate between mosquitoes and birds were the parameters that most influenced WNV invasion risk. Even though our model did not predict WNV invasion across any of the studied environments, we found that natural habitats displayed the highest susceptibility to WNV invasion. Pipiens (eco)type acted as the primary vector in all habitats. Hybrids, contrary to common opinion, showed minimal involvement in WNV transmission. However, it is important to interpret our study results with caution due to the possibility of idealized spring and summer seasons being reflected in the field-collected data. Our study could be a tool to enhance current vector surveillance and control programs by targeting specific vector types in specific environments, especially in natural habitat, which are most responsive to environmental shifts. The joint approach based on epidemiological modelling based on field collected data can help to reduce wasted time and economic costs while maximizing the efficiency of local public health authorities.

Four naturalized landbird species and 7 Galliform species are well established in Idaho. These species initially appeared in the state between 1870 to 2001 and usually became widespread within 1 or 2 decades. Combined, these 11 naturalized species account for 70.3% of all land birds counted on Idaho Christmas Bird Counts (CBC) from 1990–2018. Naturalized species made up 6.2% of land birds on Idaho Breeding Bird Surveys routes (BBS). Rock Pigeons (Columbia livia), European Starlings (Sturnus vulgaris), and House Sparrows (Passer domesticus) were the 3 most abundant land birds on 1990–2018 Idaho CBC and were common on Idaho BBS. Since 1st appearing in 2001, Eurasian Collared-Dove (Streptopelia decaocto) populations grew exponentially through the mid-2010s before declining, and were the 4th most abundant bird on Idaho CBC from 2014–2018. Northern Bobwhite (Colinus virginianus) were locally common for over a century but are now probably extirpated. Gambel's Quail (Callipepla gambelii) were introduced near the Salmon-Lemhi River confluence where a small population persists. California Quail (Callipepla californicus), Gray Partridge (Perdix perdix), Chukar (Alectoris chukar), Ring-necked Pheasant (Phasianus colchicus), and Wild Turkey (Meleagris gallopavo) ranged from the 12th to 40th most common birds on the 1990–2018 Idaho CBC and but were less common on Idaho BBS. Populations of California Quail, Gambel's Quail and Wild Turkey have been increasing, Chukar and Gray Partridge stable, and Ring-necked Pheasant decreasing. Idaho hunters annually harvest 10,000s to 100,000s of these 5 game birds. [ABSTRACT FROM AUTHOR]

The gut microbiome is important for host fitness and is influenced by many factors including the host's environment. Captive environments could potentially influence the richness and composition of the microbiome and understanding these effects could be useful information for the care and study of millions of animals in captivity. While previous studies have found that the microbiome often changes due to captivity, they have not examined how quickly these changes can occur. We predicted that the richness of the gut microbiome of wild-caught birds would decrease with brief exposure to captivity and that their microbiome communities would become more homogeneous. To test these predictions, we captured wild house sparrows (Passer domesticus) and collected fecal samples to measure their gut microbiomes immediately after capture ("wild sample") and again 5–10 days after capture ("captive sample"). There were significant differences in beta diversity between the wild and captive samples, and captive microbiome communities were more homogenous but only when using nonphylogenetic measures. Alpha diversity of the birds' microbiomes also decreased in captivity. The functional profiles of the microbiome changed, possibly reflecting differences in stress or the birds' diets before and during captivity. Overall, we found significant changes in the richness and composition of the microbiome after only a short exposure to captivity. These findings highlight the necessity of considering microbiome changes in captive animals for research and conservation purposes. [ABSTRACT FROM AUTHOR]

Characterizing spatial differences in wildlife immunity is the first step to identify environmental drivers of host defense and disease risks. The house sparrow (Passer domesticus) is a model system for ecoimmunology, but spatial differences in immunity have been largely restricted to the invasive range of this global species. We provide an initial test of spatial variation in immune response to phytohemagglutinin in the native range, finding that birds from Romania have greater inflammatory responses than birds from Egypt. Future broad surveys across the house sparrow native range could contextualize these differences and determine underlying drivers. [ABSTRACT FROM AUTHOR]

Urbanization is spreading all over the world, with more than half of the people now living in urban ecosystems. Pollutants such as metals have continuously been introduced into ecosystems as a consequence of urbanization and industrial processes. Metals can bioaccumulate in tissues of organisms. Therefore, the selection of ecological compartments such as birds as bio-indicator species can be a proper approach to monitor pollution in cities. This study aimed to measure concentrations of lead in the lungs and feathers of the house sparrow (Passer domesticus) and investigate the possibility of applying this species for air pollution monitoring in Tehran, Iran. In July and August of 2020, 50 bird specimens were collected from five regions of Tehran (north, south, east, west, and central) and 10 birds from Alborz region (as the control station). The lead concentration was measured by using a FAAS instrument after acid digestion. The results showed that the average lead concentration in feathers of five regions of Tehran (North: 42.95 ± 23.57, Central: 43.59 ± 9.58, South: 35.42 ± 3.38, East: 22.91 ± 3.24, and West: 34.36 ± 11.98 µg/g) were higher than those of the control station (14.40 ± 2.97 µg/g). Significant differences were observed between lead concentration in feathers of the birds collected from the control station and those of central, south and west of Tehran. Lead concentration in the birds' lungs in all regions of Tehran (North: 72.65 ± 17.55, Central: 20.76 ± 3.02, East: 17.88 ± 1.74, and West: 30.19 ± 13.04 µg/g) except south (13.17 ± 2.14 µg/g) were higher than the control group (14.57 ± 1.94 µg/g). However, this difference was only significant between the birds of the control station and those of north of Tehran. In this study, no significant differences were observed between lead concentrations in male and female as well as adult and juvenile sparrows. Also, no significant correlation was observed between tissue accumulation of lead in feathers and lungs. This study suggests that feathers can be used as a useful indicator of local air pollution. [ABSTRACT FROM AUTHOR]

The presence of predators can cause major changes in animal behavior, but how this interacts with hormonal state and brain activity is poorly understood. We gave female house sparrows (Passer domesticus) in post-molt condition an estradiol (n = 17) or empty implant (n = 16) for 1 week. Four weeks after implant removal, a time when female sparrows show large differences in neuronal activity to conspecific vs. heterospecific song, we exposed birds to either 30 min of conspecific song or predator calls, and video recorded their behavior. Females were then euthanized, and we examined neuronal activity using the expression of the immediate early gene (IEG) ZENK to identify how the acoustic stimuli affected neuronal activation. We predicted that if female sparrows with estradiol implants reduce neuronal activity in response to predator calls as they do to neutral tones and non-predatory heterospecifics, they would show less fear behavior and a decreased ZENK response in brain regions involved in auditory (e.g., caudomedial mesopallium) and threat perception functions (e.g., medial ventral arcopallium) compared to controls. Conversely, we predicted that if females maintain auditory and/or brain sensitivity towards predator calls, then female sparrows exposed to estradiol would not show any differences in ZENK response regardless of playback type. We found that female sparrows were less active during predator playbacks independent of hormone treatment and spent more time feeding during conspecific playback if they had previously been exposed to estradiol. We observed no effect of hormone or sound treatment on ZENK response in any region of interest. Our results suggest that female songbirds maintain vigilance towards predators even when in breeding condition. [ABSTRACT FROM AUTHOR]

Young animals often solicit care from their parents using behaviors and morphologies collectively termed begging. Many nestling altricial birds add to their familiar postures and vocalizations by displaying colorful mouthparts, hypothesized to enhance their visual conspicuousness and/or be favored by choosy parents. We evaluated these two hypotheses with experimental manipulations of the flange tissue of house sparrow (Passer domesticus) nestlings. We allowed parents to interact with nestlings that appeared to have either carotenoid-rich or carotenoid-poor flanges, and then with nestlings that appeared similar in carotenoid-richness but differed in either brightness (total light reflected) or ultraviolet (UV) richness. These three features of flange color comprise much of the variation observed both within and among species. None of our three manipulations shaped parents' ability to transfer prey efficiently to nestlings, a proxy for how visually detectable nestlings were. Parents preferentially allocated prey to nestlings that appeared carotenoid-rich, but did not bias allocation when we manipulated brightness or UV reflectance. These patterns suggest that nestlings displaying carotenoid-rich flanges benefit from parental favoritism, but that variation in brightness and UV reflectance do not independently shape parental care, at least within the range a house sparrow parent might encounter in nature. Efforts to understand mouth color in the context of offspring-parent communication and visual signal evolution may benefit from considering the component parts of color, as they may function, be constrained, and evolve independently. [ABSTRACT FROM AUTHOR]

Abstract Background The gut microbiome influences its host in a myriad of ways, from immune system development to nutrient utilization. However, our understanding of the relationship between the gut microbiome and behavior, especially in wild species, is still poor. One behavior that potentially interacts with the gut microbiome is exploratory behavior, which animals use to acquire new information from the environment. We hypothesized that diversity of the gut microbiome will be correlated with exploratory behavior in a wild-caught bird species. To test this hypothesis, we captured wild house sparrows (Passer domesticus) and collected fecal samples to measure the diversity of their gut microbiomes. We then introduced individuals to a novel environment and measured their exploratory behavior. Results We found that birds with higher alpha diversity of the gut microbiome exhibited higher exploratory behavior. These results suggest that high exploratory birds encounter more types of environmental microbes that contribute to their diverse gut microbiome compared with less exploratory birds. Alternatively, increased gut microbiome diversity may contribute to increased exploratory behavior. We also found differences in beta diversity when comparing high and low exploring birds, indicating differences in microbiome community structure. When comparing predicted functional pathways of the birds’ microbiomes, we found that the microbiomes of high explorers contained more pathways involved in biofilm formation and xenobiotic degradation than those of low explorers. Conclusions Overall, we found that the alpha and beta diversity of the gut microbiome is correlated with exploratory behavior of house sparrows. The predicted functions of the gut microbiome from high explorers differs from that of low explorers. Our study highlights the importance of considering the gut microbiome when investigating animal behavior.

Se reporta por primera vez para República Dominicana el ácaro Ornithonyssus bursa (Berlese) (Acari: Mesostigmata: Macronyssidae) y un caso de dermatitis provocado por este ácaro a humanos. El caso estuvo relacionado a una infestación de ácaros originada en nidos de Passer domesticus L. Se sospecha que casos como este podrían estar ocurriendo con más frecuencia y ser confundidos con alergias.

Birds are intermediate hosts and important reservoirs that play a significant role in Toxoplasma gondii (Apicomplexa, Sarcocystidae) epidemiology and infection transfer to humans by eating their raw or undercooked meat. The aim of this study is to diagnose the Toxoplasma gondii infection in three species of wild birds (Columba livia, Streptopelia senegalensis and Passer domesticus) in the province of Babylon from May 2021 to August 2021, using a latex agglutination test and molecular diagnosis with nested PCR for SAG1 gene identification. Results showed that antibodies were detected in 56/144 (38.88%) samples. Furthermore, results of the nested PCR technique for detection of SAG1 gene revealed that 41 (73.21%) of the samples positive for the latex agglutination test were only found in three species of birds. These three species of birds were found infected with T. gondii with possible transmission to human beings. For the first time, a S. senegalensis, was infected with the T. gondii in Iraq.

Background: The gut microbiome influences its host in a myriad of ways, from immune system development to nutrient utilization. However, our understanding of the relationship between the gut microbiome and behavior, especially in wild species, is still poor. One behavior that potentially interacts with the gut microbiome is exploratory behavior, which animals use to acquire new information from the environment. We hypothesized that diversity of the gut microbiome will be correlated with exploratory behavior in a wild-caught bird species. To test this hypothesis, we captured wild house sparrows (Passer domesticus) and collected fecal samples to measure the diversity of their gut microbiomes. We then introduced individuals to a novel environment and measured their exploratory behavior. Results: We found that birds with higher alpha diversity of the gut microbiome exhibited higher exploratory behavior. These results suggest that high exploratory birds encounter more types of environmental microbes that contribute to their diverse gut microbiome compared with less exploratory birds. Alternatively, increased gut microbiome diversity may contribute to increased exploratory behavior. We also found differences in beta diversity when comparing high and low exploring birds, indicating differences in microbiome community structure. When comparing predicted functional pathways of the birds' microbiomes, we found that the microbiomes of high explorers contained more pathways involved in biofilm formation and xenobiotic degradation than those of low explorers. Conclusions: Overall, we found that the alpha and beta diversity of the gut microbiome is correlated with exploratory behavior of house sparrows. The predicted functions of the gut microbiome from high explorers differs from that of low explorers. Our study highlights the importance of considering the gut microbiome when investigating animal behavior. [ABSTRACT FROM AUTHOR]

The house sparrow (Passer domesticus) is a valuable avian model for studying evolutionary genetics, development, neurobiology, physiology, behavior, and ecology, both in laboratory and field-based settings. The current annotation of the P. domesticus genome available at the Ensembl Rapid Release site is primarily focused on gene set building and lacks functional information. In this study, we present the first comprehensive functional reannotation of the P. domesticus genome using intestinal Illumina RNA sequencing (RNA-Seq) libraries. Our revised annotation provides an expanded view of the genome, encompassing 38592 transcripts compared to the current 23574 transcripts in Ensembl. We also predicted 14717 protein-coding genes, achieving 96.4% completeness for Passeriformes lineage BUSCOs. A substantial improvement in this reannotation is the accurate delineation of untranslated region (UTR) sequences. We identified 82.7% and 93.8% of the transcripts containing 5′- and 3′-UTRs, respectively. These UTR annotations are crucial for understanding post-transcriptional regulatory processes. Our findings underscore the advantages of incorporating additional specific RNA-Seq data into genome annotation, particularly when leveraging fast and efficient data processing capabilities. This functional reannotation enhances our understanding of the P. domesticus genome, providing valuable resources for future investigations in various research fields. [ABSTRACT FROM AUTHOR]

House Sparrows (Passer domesticus) are ubiquitous wild birds and can be potential reservoirs of avian haemosporidians (vector-borne blood parasites) in their habitat. The Zagros Mountain range in western Iran is an important habitat of many endangered birds. To investigate the occurrence and molecular characterization of Haemoproteus and Plasmodium spp. in Kuhdasht County in the central western region of Zagros, blood samples from 60 House Sparrows were screened by microscopic examination and PCR. An overall prevalence of 6.6%, with a varied intensity of infection (1–198 parasites per 15,000 erythrocytes) for Haemoproteus spp. and no infection for Plasmodium spp., was observed by microscopy. One of the studied cytochrome b sequences was identical to the lineage PAHIS1, and the other sequence was a new lineage, PADOM41; both were extremely similar to Haemoproteus passeris. This is the first report on the molecular detection and characterization of Haemoproteus in passerines of Kuhdasht. [ABSTRACT FROM AUTHOR]

The presence of predators can cause major changes in animal behavior, but how this interacts with hormonal state and brain activity is poorly understood. We gave female house sparrows (Passer domesticus) in post-molt condition an estradiol (n = 17) or empty implant (n = 16) for 1 week. Four weeks after implant removal, a time when female sparrows show large differences in neuronal activity to conspecific vs. heterospecific song, we exposed birds to either 30 min of conspecific song or predator calls, and video recorded their behavior. Females were then euthanized, and we examined neuronal activity using the expression of the immediate early gene (IEG) ZENK to identify how the acoustic stimuli affected neuronal activation. We predicted that if female sparrows with estradiol implants reduce neuronal activity in response to predator calls as they do to neutral tones and non-predatory heterospecifics, they would show less fear behavior and a decreased ZENK response in brain regions involved in auditory (e.g., caudomedial mesopallium) and threat perception functions (e.g., medial ventral arcopallium) compared to controls. Conversely, we predicted that if females maintain auditory and/or brain sensitivity towards predator calls, then female sparrows exposed to estradiol would not show any differences in ZENK response regardless of playback type. We found that female sparrows were less active during predator playbacks independent of hormone treatment and spent more time feeding during conspecific playback if they had previously been exposed to estradiol. We observed no effect of hormone or sound treatment on ZENK response in any region of interest. Our results suggest that female songbirds maintain vigilance towards predators even when in breeding condition.

¿Audaz o tímido? Examinando el comportamiento de toma de riesgo y neofobia de los gorriones comunes invasivos y no invasivos Dado que el comportamiento proporciona un marco útil para comprender la especialización, la personalidad animal puede ayudar a explicar la capacidad invasiva de las aves. La invasión implica la dispersión por áreas desconocidas y podría requerir cambios en el comportamiento o agrupaciones espaciales basadas en la personalidad. La reducción de la neofobia y el aumento del comportamiento de exploración podrían permitir a los individuos colonizar nuevas áreas a medida que prueban y utilizan recursos que no les son familiares. En este trabajo suponemos que los individuos de gorrión común (Passer domesticus) mostrarán un comportamiento más audaz en las poblaciones invasivas que en las poblaciones no invasivas. En este estudio evaluamos la toma de riesgo y la neofobia en machos de gorrión común de Barcelona (donde se considera nativo) y de Ciudad de México (donde es invasivo) capturados en dos hábitats diferentes (urbano y no urbano). Evaluamos la latencia para entrar en la jaula experimental y para explorarla, así como la latencia para alimentarse y el tiempo de alimentación en presencia de un objeto extraño. Encontramos que los gorriones de Ciudad de México, tanto de hábitats urbanos como no urbanos, entraron más rápido en la jaula experimental que los gorriones de Barcelona. El resultado fue similar para el tiempo que les tomó comenzar a explorar la jaula. No encontramos diferencias entre ciudades y hábitats en cuanto a la latencia para alimentarse y el tiempo que les tomó alimentarse en presencia de un objeto extraño. Nuestros resultados apoyan parcialmente la idea de que las poblaciones invasivas de Ciudad de México son más atrevidas que las de Barcelona. El comportamiento es un componente importante de la plasticidad y su variabilidad puede tener un efecto importante en la adaptación a situaciones locales. Se deberían llevar a cabo otros estudios para desentrañar los mecanismos que explican las diferencias de personalidad que se encuentran entre poblaciones de distintos orígenes, así como comparando poblaciones con diferente densidad demográfica y teniendo en cuenta diferentes contextos de disponibilidad de alimentos.

In recent decades, there has been a decline of the House Sparrow (Passer domesticus), mainly in European cities, and several hypotheses have been proposed that attempt to determine the causes of this rapid decline. Previous studies indicated that house sparrows were significantly negatively associated with increasing electromagnetic radiation and sparrows disappeared from areas most polluted. In addition, there are many studies on the impact of radiation on other bird and non-bird species, as well as numerous laboratory studies that demonstrated detrimental effects at electric field strength levels that can be found in cities today. Electromagnetic radiation is the most plausible factor for multiple reasons, including that this is the only one that affects the other hypotheses proposed so far. It is a type of pollution that affects productivity, fertility, decreases insects (chicken feed), causes loss of habitat, decreases immunity and can promote disease. Additionally, the recent sparrow decline matches the deployment of mobile telephony networks. Further, there are known mechanisms of action for non-thermal effects of electromagnetic radiation that may affect sparrows causing their decline. Thus, electromagnetic radiation must be seriously considered as a factor for house sparrows’ decline, probably in synergy with the other factors previously proposed.

Urban planning and management need long-term population level studies for evaluating how urbanization influences biodiversity. Firstly, we reviewed the current population trends of the House Sparrow (Passer domesticus) and the Eurasian Tree Sparrow (Passer montanus) in Europe, and evaluated the usefulness of citizens’ science projects to monitor these species in Finland. Secondly, we conducted a long-term (1991–2020) winter field study in 31 urban settlements along a 950 km north–south extent in Finland to study how latitude, weather and urbanization influence on sparrow’s growth rates. The House Sparrow is declining in 15 countries, and increasing in 5, whereas the Eurasian Tree Sparrow is declining in 12 and increasing in 9 European countries. The trend of the House Sparrow was significantly negative in continental Europe. However, the trend of the Eurasian Tree Sparrow was not significant. Both species have declined simultaneously in six countries, whereas in four countries, their trends are opposite. Citizen-based, long-term (2006–2020) winter season project data indicated that House Sparrow has decreased, whereas Eurasian Tree Sparrow has increased in Finland. However, the short-term (2013–2020) breeding season citizen-based project data did not indicate significant changes in the occupation rate of sparrows. Our long-term (1991–2020) field study indicated that wintering populations of the House Sparrow have decreased, whereas the Eurasian Tree Sparrows have both expanded their wintering range and increased their population size. Based on our winter count data, latitude and weather did not significantly influence the growth rates of sparrows. When the human population increased within the study plot, House Sparrow populations decreased, and vice versa. There was also a trend that a decreasing number of feeding sites has decreased the House Sparrow numbers. Urban-related factors did not influence the growth rate of the Eurasian Tree Sparrow. Our results indicate that the colonization of a new, even closely related species does not influence negatively on earlier urbanized species. It is probable that the niches of these sparrow species are different enough for allowing them to co-occur. The House Sparrow mainly nests on buildings, whereas the Eurasian Tree Sparrow can easily accept, e.g., nest boxes. Urban planning should take care of both the food availability and nest sites availability for both sparrow species.

Offspring of older parents in many species have decreased longevity, a faster ageing rate and lower fecundity than offspring born to younger parents. Biomarkers of ageing, such as telomeres, that tend to shorten as individuals age, may provide insight into the mechanisms of such parental age effects. Parental age may be associated with offspring telomere length either directly through inheritance of shortened telomeres or indirectly, for example, through changes in parental care in older parents affecting offspring telomere length. Across the literature there is considerable variation in estimates of the heritability of telomere length, and in the direction and extent of parental age effects on telomere length. To address this, we experimentally tested how parental age is associated with the early-life telomere dynamics of chicks at two time points in a captive population of house sparrows Passer domesticus. We experimentally separated parental age from sex effects, and removed effects of age-assortative mating, by allowing the parent birds to only mate with young, or old partners. The effect of parental age was dependent on the sex of the parent and the chicks, and was found in the father-daughter relationship only; older fathers produced daughters with longer telomere lengths post-fledging. Overall we found that chick telomere length increased between the age of 0.5 and 3 months at the population and individual level. This finding is unusual in birds with such increases more commonly associated with non-avian taxa. Our results suggest parental age effects on telomere length are sex-specific either through indirect or direct inheritance. The study of similar patterns in different species and taxa will help us further understand variation in telomere length and its evolution. [ABSTRACT FROM AUTHOR]

Maximum and minimum metabolic rates in birds are flexible traits and such flexibility can be advantageous in variable climates. The climatic variability hypothesis (CVH) posits that more variable climates should result in greater metabolic flexibility for geographically distinct populations. Whether the CVH applies to sympatric species occupying microclimates differing in variability is unknown. Microclimates of open habitats are likely more variable than those of sheltered habitats. If the CVH extends to microclimates, we expect birds from open habitats to show greater flexibility than those from sheltered habitats. To test this extension of the CVH, we compared seasonal variation in microclimates and metabolic rates for sympatric horned larks Eremophila alpestris , which occupy open habitats, and house sparrows Passer domesticus , which occupy sheltered habitats. We measured operative temperature (T e, an integrative measure of the thermal environment), summit metabolic rate (M sum, maximal cold-induced metabolic rate), and basal metabolic rate (BMR, minimal maintenance metabolic rate) in summer and winter. For both winter and summer, daily minimum T e was similar between open and sheltered habitats but maximum T e was higher for open habitats. Winter microclimates, however, were colder for open than for sheltered habitats after accounting for convective differences. Both species increased M sum in winter, but seasonal M sum flexibility was greater for larks (43%) than for sparrows (31%). Winter increases in BMR were 92.5% and 11% for larks and sparrows, respectively, with only the former attaining statistical significance. Moreover, species * season interactions in general linear models for whole-organism metabolic rates were significant for BMR and showed a similar, although not significant, pattern for M sum, with greater seasonal metabolic flexibility in horned larks than in house sparrows. These results suggest that extending the CVH to sympatric bird species occupying different microclimates may be valid. [ABSTRACT FROM AUTHOR]

Offspring of older parents in many species have decreased longevity, a faster ageing rate and lower fecundity than offspring born to younger parents. Biomarkers of ageing, such as telomeres, that tend to shorten as individuals age, may provide insight into the mechanisms of such parental age effects. Parental age may be associated with offspring telomere length either directly through inheritance of shortened telomeres or indirectly, for example, through changes in parental care in older parents affecting offspring telomere length. Across the literature there is considerable variation in estimates of the heritability of telomere length, and in the direction and extent of parental age effects on telomere length. To address this, we experimentally tested how parental age is associated with the early-life telomere dynamics of chicks at two time points in a captive population of house sparrows Passer domesticus. We experimentally separated parental age from sex effects, and removed effects of age-assortative mating, by allowing the parent birds to only mate with young, or old partners. The effect of parental age was dependent on the sex of the parent and the chicks, and was found in the father-daughter relationship only; older fathers produced daughters with longer telomere lengths post-fledging. Overall we found that chick telomere length increased between the age of 0.5 and 3 months at the population and individual level. This finding is unusual in birds with such increases more commonly associated with non-avian taxa. Our results suggest parental age effects on telomere length are sex-specific either through indirect or direct inheritance. The study of similar patterns in different species and taxa will help us further understand variation in telomere length and its evolution.

There is increasing evidence of social information transfer about predation risk in foraging animal groups. However, little is known about whether individuals also acquire such information from non-members of their own group. We experimentally manipulated the perceived threat and heterospecific cues about low predation risk in the house sparrow, Passer domesticus, by presenting stuffed dummies of the Eurasian sparrowhawk, Accipiter nisus, and the Eurasian tree sparrow, Passer montanus, at the feeder. Data were collected during winter 2016/2017 in two private yards in south-west and north Slovakia, where 1677 individuals in 83 flocks were observed at two feeders. We found no evidence for heterospecific information use in foraging single-species flocks of house sparrows. We suggest that strong bonds created among flock members may explain the observed pattern. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Basrah Researches (Sciences) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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.)

Mapping of the nests of house sparrows was carried out in 14 sampling areas in Western and Central Siberia. Quantitative assessments of nest interpositions were analyzed using the distance to the nearest neighboring nest. Cartographic visualization showed a cluster distribution of the nests. The average cluster size in different areas varied from 2.7 to 8.1 nests per cluster. No correlation was found either between their size and geographical location or their population density. No aggregations of higher rank were identified. The clusters recognized were defined as individual colonies. The distribution patterns of the frequencies of the distances to the nearest neighbor were found to be strongly exponential. Slightly more than half of all nests were located closer than 10 m to the nearest neighboring nest, and about three-quarters were located closer than 20 m. The maximum distance to the nearest neighbor inside a single colony did not exceed 80 m. No reliable indicators of isolated nesting in the house sparrow were identified. Colonies were distributed independently of one another, the distance between adjacent colonies being less where the population density was higher. Territories with closely spaced colonies could alternate with unpopulated, but suitable areas (sometimes of significant sizes). [ABSTRACT FROM AUTHOR]

Abstract Background Avian malaria parasites are a highly diverse group that commonly infect birds and have deleterious effects on their hosts. Some parasite lineages are geographically widespread and infect many host species in many regions. Bird migration, natural dispersal, invasive species and human-mediated introductions into areas where competent insect vectors are present, are probably the main drivers of the current distribution of avian malaria parasites. Methods A total of 412 and 2588 wild house sparrows (Passer domesticus) were captured in 2012 and 2013 in two areas of the Iberian Peninsula (central and southern Spain, respectively). Genomic DNA was extracted from blood samples; parasite lineages were sequenced and identified by comparing with GenBank and/or MalAvi databases. Results Thirteen Plasmodium lineages were identified in house sparrows corresponding to three major clades. Five individuals were infected by the African Plasmodium lineage PAGRI02, which has been proposed to actively circulate only in Africa. Conclusions Despite the low prevalence of PAGRI02 in sparrows in Spain, our results suggest that the area of transmission of this parasite is more widespread than previously thought and covers both Africa and Europe. Further studies of the global distribution of Plasmodium lineages infecting wild birds are required to identify the current transmission areas of these parasites. This is vital given the current scenario of global change that is providing new opportunities for avian malaria transmission into areas where parasites were previously absent.

Large baobabs are regarded as key plant species in the savannah biome. In this study their role in shaping the avian community has been evaluated. The territory mapping method has been employed to quantify the avian breeding community in the town Outapi (ca. 130 ha), Northern Namibia, well-endowed with large baobabs. A total of 29 breeding bird species were recorded. The alien House Sparrow was by far the most numerous species comprising 48.4% of all breeding birds. The Blue Waxbill and African Palm Swift were also classified as dominant species, comprising together 17.4%. Granivores were by far the most numerous feeding guild, comprising 77.2% of all birds breeding, while the insectivores comprised only 11.8%. Birds nesting in/on buildings comprised 52.7%, those nesting on trees/shrubs – 42.0%. The population densities of many bird species (e.g. doves from the genus Stepropelia, bulbuls, weavers) were comparatively low. Such a situation could have been caused by the exceptionally high population density of the Pied Crow. In the study area, there were 15 breeding pairs and about 100–150 non-breeding individuals. The baobabs may provide them with a feeding resource in the form of the sweet fruits. The crows, as nest predators, feed also on the eggs and nestlings of other birds. Doves seem to be especially prone to such predation, as their nests are easily to detect and destroy. As a result, they have to breed in low density. This in turn, may release other dominant granivores in the study area, namely sparrows. They are not vulnerable to crow nest predation, as their nests are usually well-concealed under eaves and in holes of buildings.

Densitat de població i estructura d’una comunitat d’ocells reproductors en un hàbitat suburbà del sistema de drenatge de Cuvelai, al nord de Namíbia En un suburbi (100 ha aproximadament) d’Ongwediva es van registrar un total de 30 espècies d’ocells reproductors el 2018. L’índex de diversitat de Shannon va ser de 2,01. L’estudi va revelar que Passer domesticus suposa gairebé la meitat de totes les parelles reproductores (36,4 parelles / 10 ha). Els granívors són, amb gran diferència, el grup més nombrós segons l’alimentació, amb el 77,5 % de tots els ocells reproductors. Els ocells que nien en edificis només estan representats per dues espècies, però constitueixen gairebé la meitat (49,9 %) de tots els ocells reproductors. En comparació amb altres ciutats del sud d’Àfrica, el nombre d’espècies d’ocells reproductors d’Ongwediva és baix, tot i que es compensa amb altes densitats de població d’algunes espècies.

In recent decades, there has been a decline of the House Sparrow (Passer domesticus), mainly in European cities, and several hypotheses have been proposed that attempt to determine the causes of this rapid decline. Previous studies indicated that house sparrows were significantly negatively associated with increasing electromagnetic radiation and sparrows disappeared from areas most polluted. In addition, there are many studies on the impact of radiation on other bird and non-bird species, as well as numerous laboratory studies that demonstrated detrimental effects at electric field strength levels that can be found in cities today. Electromagnetic radiation is the most plausible factor for multiple reasons, including that this is the only one that affects the other hypotheses proposed so far. It is a type of pollution that affects productivity, fertility, decreases insects (chicken feed), causes loss of habitat, decreases immunity and can promote disease. Additionally, the recent sparrow decline matches the deployment of mobile telephony networks. Further, there are known mechanisms of action for non-thermal effects of electromagnetic radiation that may affect sparrows causing their decline. Thus, electromagnetic radiation must be seriously considered as a factor for house sparrows' decline, probably in synergy with the other factors previously proposed. [ABSTRACT FROM AUTHOR]

Urban planning and management need long-term population level studies for evaluating how urbanization influences biodiversity. Firstly, we reviewed the current population trends of the House Sparrow (Passer domesticus) and the Eurasian Tree Sparrow (Passer montanus) in Europe, and evaluated the usefulness of citizens' science projects to monitor these species in Finland. Secondly, we conducted a long-term (1991-2020) winter field study in 31 urban settlements along a 950 km north--south extent in Finland to study how latitude, weather and urbanization influence on sparrow's growth rates. The House Sparrow is declining in 15 countries, and increasing in 5, whereas the Eurasian Tree Sparrow is declining in 12 and increasing in 9 European countries. The trend of the House Sparrow was significantly negative in continental Europe. However, the trend of the Eurasian Tree Sparrow was not significant. Both species have declined simultaneously in six countries, whereas in four countries, their trends are opposite. Citizen-based, long-term (2006--2020) winter season project data indicated that House Sparrow has decreased, whereas Eurasian Tree Sparrow has increased in Finland. However, the short-term (2013-2020) breeding season citizen-based project data did not indicate significant changes in the occupation rate of sparrows. Our long-term (1991-2020) field study indicated that wintering populations of the House Sparrow have decreased, whereas the Eurasian Tree Sparrows have both expanded their wintering range and increased their population size. Based on our winter count data, latitude and weather did not significantly influence the growth rates of sparrows. When the human population increased within the study plot, House Sparrow populations decreased, and vice versa. There was also a trend that a decreasing number of feeding sites has decreased the House Sparrow numbers. Urban-related factors did not influence the growth rate of the Eurasian Tree Sparrow. Our results indicate that the colonization of a new, even closely related species does not influence negatively on earlier urbanized species. It is probable that the niches of these sparrow species are different enough for allowing them to co-occur. The House Sparrow mainly nests on buildings, whereas the Eurasian Tree Sparrow can easily accept, e.g., nest boxes. Urban planning should take care of both the food availability and nest sites availability for both sparrow species. [ABSTRACT FROM AUTHOR]

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance 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.)

Increasing urbanisation and human pressure on lands have huge impacts on biodiversity. Some species, known as "urban exploiters", manage to expand in urban landscapes, relying on human resources. The House Sparrow (Passer domesticus) is the perfect example of a human-commensal species. Surprisingly, this urban exploiter has been declining all over Europe over the past decades. The proximate causes of this decline remain poorly understood. We particularly lack understanding about urban habitat characteristics that are particularly unfavourable for House Sparrows. In the present study, we analysed fine-scale habitat characteristics of House Sparrow population sizes and trends using a fifteen-year House Sparrow census (2003–2017) covering the urban diversity of Paris (nearly 200 census sites), one of the densest European cities. We documented for the first time the dramatic decline (−89%) of the species in Paris over the study period. The temporal decline over the whole city correlates with the concomitant increase in the number of breeding Sparrowhawks. We could not detect statistical influences of annual variations in weather conditions and pollution. The decline of House Sparrows is spatially heterogeneous. Indeed, site-scale analyses revealed sharpest declines at sites that initially hosted the largest numbers of sparrows, which are areas with a relatively high proportion of green spaces and new buildings. Further experimental studies are now needed to disentangle the exact impact of specific characteristics of the urban environment on House Sparrow populations. [ABSTRACT FROM AUTHOR]

Bacteria are known to exert positive and negative influences on animals’ health and fitness. Bacteria, in particular those inhabiting the skin and inner organs of vertebrates, are horizontally or vertically transmitted. Specifically, mothers of bird species can transfer bacterial strains to their offspring when the egg is passing the reproductive tract, as the eggshell rubs against the wall of the uterus. In this context, the female immune system might play an important role in influencing the vertical transmission of bacteria. Here, we investigate the relationship between the major histocompatibility complex (MHC) and cultivable eggshell bacteria originating putatively from the female urogenital tract in a captive population of house sparrows (Passer domesticus). We predict that females with a more variable MHC will transfer fewer bacteria onto the eggshells. Our results show a negative relationship between the number of functional MHC class I alleles and bacteria originating in the urinary tract and growing on a selective medium. This is the first study to find a correlation between female MHC diversity and eggshell bacteria.

Birds secrete preen oil from the uropygial (preen) gland which is used to maintain feather integrity and communicate through odour. The uropygial secretion is believed to influence host attractiveness to biting insects, thereby altering the risk of infection by vector‐transmitted blood parasites. Previous studies have documented a presence of bacteria in the uropygial secretion; however, the microbial community in the gland is still largely unknown. In addition, we have no information yet as to whether there are any associations between these uropygial gland microbes and haemosporidian parasite infection. Here, we characterise the microbiome of the uropygial gland secretion in 23 wild‐caught house sparrows Passer domesticus from Peru and investigate whether individuals with natural malaria Plasmodium infection have different preen oil microbiota than uninfected birds. We found no differences in microbial alpha diversity or richness, and malaria infection explained approximately 5% of the overall microbiome composition, however, this was not statistically significant. On the other hand, birds with malaria infection had significantly higher abundances of bacteria from the genera Arthrobacter and Micrococcus in their gland, whereas uninfected birds harboured higher abundances of Rhodococcus, Phenylobacterium and Enhydrobacter. These first results of the uropygial gland microbiome in malaria‐infected birds illustrate the presence of a more specific relationship between certain members of the gland microbiota and Plasmodium parasites in birds, which opens up new questions on the role of the uropygial gland in avian health.

Vector‐borne diseases, especially those transmitted by mosquitoes, have severe impacts on public health and economy. West Nile virus (WNV) and avian malaria parasites of the genus Plasmodium are mosquito‐borne pathogens that may produce severe disease and illness in humans and birds, respectively, and circulate in an endemic form in southern Europe. Here, we used field‐collected data to identify the impact of Culex pipiens, Cx. perexiguus and Cx. modestus, on the circulation of both WNV and Plasmodium in Andalusia (SW Spain) using mathematical modelling of the basic reproduction number (R0). Models were calibrated with field‐collected data on WNV seroprevalence and Plasmodium infection in wild house sparrows, presence of WNV and Plasmodium in mosquito pools, and mosquito blood‐feeding patterns. This approach allowed us to determine the contribution of each vector species to pathogen amplification. Overall, 0.7% and 29.6% of house sparrows were positive to WNV antibodies and Plasmodium infection, respectively. In addition, the prevalence of Plasmodium was higher in Cx. pipiens (2.0%), followed by Cx. perexiguus (1.8%) and Cx. modestus (0.7%). Three pools of Cx. perexiguus were positive to WVN. Models identified Cx. perexiguus as the most important species contributing to the amplification of WNV in southern Spain. For Plasmodium models, R0 values were higher when Cx. pipiens was present in the population, either alone or in combination with the other mosquito species. These results suggest that the transmission of these vector‐borne pathogens depends on different Culex species, and consequently, their transmission niches will present different spatial and temporal patterns. For WNV, targeted surveillance and control of Cx. perexiguus populations appear as the most effective measure to reduce WNV amplification. Also, preventing Culex populations near human settlements, or reducing the abundance of these species, are potential strategies to reduce WNV spillover into human populations in southern Spain. [ABSTRACT FROM AUTHOR]

The article explores nest predation is the primary cause of nest failure in passerines. In order to contribute to our understanding of how nest predators shape avian nesting ecology and life history traits, we report nest predator identity and nest predation rates for 3 species of passerines in the Central Andes of south temperate Argentina.

Birds secrete preen oil from the uropygial (preen) gland which is used to maintain feather integrity and communicate through odour. The uropygial secretion is believed to influence host attractiveness to biting insects, thereby altering the risk of infection by vector‐transmitted blood parasites. Previous studies have documented a presence of bacteria in the uropygial secretion; however, the microbial community in the gland is still largely unknown. In addition, we have no information yet as to whether there are any associations between these uropygial gland microbes and haemosporidian parasite infection. Here, we characterise the microbiome of the uropygial gland secretion in 23 wild‐caught house sparrows Passer domesticus from Peru and investigate whether individuals with natural malaria Plasmodium infection have different preen oil microbiota than uninfected birds. We found no differences in microbial alpha diversity or richness, and malaria infection explained approximately 5% of the overall microbiome composition, however, this was not statistically significant. On the other hand, birds with malaria infection had significantly higher abundances of bacteria from the genera Arthrobacter and Micrococcus in their gland, whereas uninfected birds harboured higher abundances of Rhodococcus, Phenylobacterium and Enhydrobacter. These first results of the uropygial gland microbiome in malaria‐infected birds illustrate the presence of a more specific relationship between certain members of the gland microbiota and Plasmodium parasites in birds, which opens up new questions on the role of the uropygial gland in avian health. [ABSTRACT FROM AUTHOR]

Dietary flexibility in digestive enzyme activity is widespread in vertebrates but mechanisms are poorly understood. When laboratory rats are switched to a higher carbohydrate diet, the activities of the apical intestinal α-glucosidases (AGs) increase within 6– 12 h, mainly by rapid increase in enzyme transcription, followed by rapid translation and translocation to the intestine’s apical, brush-border membrane (BBM). We performed the first unified study of the overall process in birds, relying on activity, proteomic, and transcriptomic data from the same animals. Our avian model was nestling house sparrows (Passer domesticus), which switch naturally from a low-starch insect diet to a higher starch seed diet and in whom the protein sucrase-isomaltase (SI) is responsible for all maltase and sucrase intestinal activities. Twenty-four hours after the switch to a high-starch diet, SI activity was increased but not at 12 h post diet switch. SI was the only hydrolase increased in the BBM, and its relative abundance and activity were positively correlated. Twenty-four hours after a reverse switch back to the lower starch diet, SI activity was decreased but not at 12 h post diet switch. Parallel changes in SI mRNA relative abundance were associated with the changes in SI activity in both diet-switch experiments, but our data also revealed an apparent diurnal rhythm in SI mRNA. This is the first demonstration that birds may rely on rapid increase in abundance of SI and its mRNA when adjusting to high-starch diet. Although the mechanisms underlying dietary induction of intestinal enzymes seem similar in nestling house sparrows and laboratory rodents, the time course for modulation in nestlings seemed half as fast compared with laboratory rodents. Before undertaking modulation, an opportunistic forager facing limited resources might rely on more extensive or prolonged environmental sampling, because the redesign of the intestine’s hydrolytic capacity shortly after just one or a few meals of a new substrate might be a costly mistake. [ABSTRACT FROM AUTHOR]

From the northernmost tip of Scandinavia to the southernmost corner of Patagonia, and across six continents, house sparrows (Passer domesticus) inhabit most human-modified habitats of the globe. With over 7,000 articles published, the species has become a workhorse for not only the study of self-urbanized wildlife, but also for understanding life history and body size evolution, sexual selection and many other biological phenomena. Traditionally, house sparrows were studied for their adaptations to local biotic and climatic conditions, but more recently, the species has come to serve as a focus for studies seeking to reveal the genomic, epigenetic and physiological underpinnings of success among invasive vertebrate species. Here, we review the natural history of house sparrows, highlight what the study of these birds has meant to bioscience generally, and describe the many resources available for future work on this species.

Birds invest time and resources in escape behaviors, thus changing their foraging strategies, habitat selection, and even reproduction. Flight initiation distance (FID) and the distance at which birds detect a threat, alert distance (AD), have been used as indicators of the ability of birds to detect potential predators. In this study we compared the two aforementioned measures of risk reaction for the House sparrow and the Orange-breasted bunting, two bird species inhabiting the same urban areas, and assessed if they were related with sex, flock size, and environmental factors. We performed generalized linear mixed models (GLMM) to explore the relationships between environmental factors and ADs and FIDs. Both behavioral responses were significantly lower for House sparrows. Although we did not find significant relationships between the assessed variables (sex, flock size, environmental factors) and bunting ADs and FIDs, we did find House sparrow males to be bolder (showing shorter ADs and FIDs), as well as larger ADs and FIDs for sparrows with increasing flock size. House sparrow ADs and FIDs were positively related with herbaceous plant cover and negatively related with minimum building height. In general, House sparrows showed to be bolder than Orange-breasted buntings, with differential responses of the sparrow related with sex, flock size, and different environmental factors. Having recorded bolder House sparrow males could be due to increases in aggressiveness related to the breeding season. Our results add to the lacking behavioral information available for the endemic Orange-breasted bunting and provide insights on the variation of the behavior of House sparrows in small urban areas. [ABSTRACT FROM AUTHOR]

Variation in rachis (central shaft) morphology in individual remiges (flight feathers) within and among species reflects adaptations to requirements imposed by aerodynamic forces, but the fine-scale variation of feather morphology across remiges is not well known. Here we describe how the shape of the rachis, expressed by the height/width ratio, changes along the longitudinal and lateral axis of the wing in four bird species with different flight styles: flapping-soaring (white storks), flapping-gliding (common buzzards), passerine-type (house sparrows) and continuous flapping (pygmy cormorants). Overall, in each wing feather, irrespective of species identity, rachis shape changed from circular to rectangular, from the base towards the feather tip. The ratio between the height and width of the calamus was similar across remiges in all species, whereas the ratio at the base, middle and tip of the rachis changed among flight feathers and species. In distal primaries of white storks and common buzzards, the ratio decreased along the feather shaft, indicating a depressed (wider than high) rachis cross section towards the feather tip, whereas the inner primaries and secondaries became compressed (higher than wide). In house sparrows, the rachis was compressed in each of the measurement points, except at the distal segment of the two outermost primary feathers. Finally, in pygmy cormorants, the width exceeds the height at each measurement point, except at the calamus. Our results may reflect the resistance of the rachis to in-plane and out-of-plane aerodynamic forces that vary across remiges and across study species. A link between rachis shape and resistance to bending from aerodynamic forces is further indicated by the change of the second moment of areas along the wing axes. [ABSTRACT FROM AUTHOR]

Biological invasions are the second most important cause of species extinction. Aided by processes such as transportation and urbanization, exotic species can establish and spread to new locations, causing changes in the function and structure of ecosystems. The House Sparrow is a widespread and highly abundant landbird associated to human presence. Previous studies performed in urban landscapes have suggested that this species could be acting, in synergy with urbanization, as a potential threat to native urban avian assemblages. In this study we assessed the relationship between House Sparrow density and native bird species richness in a region where the sparrows are scarce and sparsely distributed. We surveyed bird assemblages in and around four small-sized human settlements, considering three conditions in relation to House Sparrow presence: urban invaded, urban non-invaded, and non-urban non-invaded. To assess the potential detrimental role of House Sparrows on native bird species richness, we measured, additionally to sparrow densities, 20 predictor variables that describe vegetation structure and complexity, as well as urban infrastructure and human activities across four seasons of 1 year. Our results show that maximum shrub height was positively related to bird species richness, built cover was negatively associated with it, and House Sparrow invaded sites were related to a significant decrease of bird species richness, with increasing richness loss when more sparrows were present. Thus, we here provide evidence that urban areas can act in synergy with the presence of House Sparrows (even in low densities) in the urban-related species richness decline pattern. [ABSTRACT FROM AUTHOR]