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Within breeding years, male birds vary in their reproductive strategy. While some maintain monogamy with a social partner, others also engage with extrapair partners, while others forgo monogamy altogether in favour of exclusively seeking extrapair paternity. Although theory predicts that extrapair paternity is beneficial to males, which sire extrapair offspring without investing in costly parental care, empirical examples from wild populations are sparse. We used 17 years of data from a closed population of house sparrows, Passer domesticus , with a complete genetic pedigree, to test the hypothesis that extrapair paternity increases male lifetime reproductive success. We compared a mixed strategy of within-pair (or social) and extrapair paternity with total genetic monogamy and total extrapair paternity. We demonstrate that males who combine within-pair and extrapair paternity have increased reproductive success against the other two groups. Our results also suggest that males that exclusively seek extrapair paternity have the lowest lifetime fitness. Overall, we provide an empirical demonstration of the theory, showing that where males can sire extrapair offspring alongside within-pair offspring, extrapair paternity is beneficial to male lifetime fitness. • Within years, male house sparrows invested in social or extrapair offspring, or both. • Within a year, reproductive strategy depended on the environmental context. • Males that had extrapair and social offspring had the highest lifetime fitness. • Floating males, which only had extrapair offspring, had the lowest lifetime fitness. [ABSTRACT FROM AUTHOR]

Parasitism results in substantial costs to hosts, which can manifest in a variety of ways. Ectoparasites, especially those that are hematophagous, can deplete the host's nutritional resources and induce costly immunological responses. Such costs can be especially relevant to neonatal animals, who also have to invest in growth and development. We used a cavity-nesting songbird species (House Sparrows; Passer domesticus) to address three main objectives related to the costs of ectoparasitism. First, we examined how abundance of ectoparasitic taxa in nests varied as a function of season. We found that fleas and blowflies were the primary ectoparasites, and were found nearly exclusively in the first or second half of the breeding season, respectively. Second, we used the insecticide permethrin to manipulate ectoparasite abundance and measured nestling body mass, circulating levels of nutrients (i.e., glucose, glycerol, and triglycerides), oxidative damage (i.e., d-ROMs), antibody levels (i.e., IgY), survival during the nestling stage, and detection of juveniles after they left the nest (i.e., post-fledging). An experimental reduction of parasites resulted in nestlings that circulated higher levels of hemoglobin and IgY, and were also likely to fledge earlier. Third, we tested if metrics collected during the nestling period predicted probability of detection post-fledging. We found a positive correlation between nestling triglyceride levels and likelihood of detection during the post-fledging stage. Thus, ectoparasitic taxa vary seasonally and have a measurable impact on nestling physiology. However, short-term survival or dispersal may be shaped predominately by nutrition, rather than ectoparasitism. [ABSTRACT FROM AUTHOR]

Measuring parental care behaviour in the wild is central to the study of animal ecology and evolution, but it is often labour‐ and time‐intensive. Efficient open‐source tools have recently emerged that allow animal behaviour to be quantified from videos using machine learning and computer vision techniques, but there is limited appraisal of how these tools perform compared to traditional methods. To gain insight into how different methods perform in extracting data from videos taken in the field, we compared estimates of the parental provisioning rate of wild house sparrows Passer domesticus from video recordings. We compared four methods: manual annotation by experts, crowd‐sourcing, automatic detection based on the open‐source software DeepMeerkat, and a hybrid annotation method. We found that the data collected by the automatic method correlated with expert annotation (r = 0.62) and further show that these data are biologically meaningful as they predict brood survival. However, the automatic method produced largely biased estimates due to the detection of non‐visitation events, while the crowd‐sourcing and hybrid annotation produced estimates that are equivalent to expert annotation. The hybrid annotation method takes approximately 20% of annotation time compared to manual annotation, making it a more cost‐effective way to collect data from videos. We provide a successful case study of how different approaches can be adopted and evaluated with a pre‐existing dataset, to make informed decisions on the best way to process video datasets. If pre‐existing frameworks produce biased estimates, we encourage researchers to adopt a hybrid approach of first using machine learning frameworks to preprocess videos, and then to do manual annotation to save annotation time. As open‐source machine learning tools are becoming more accessible, we encourage biologists to make use of these tools to cut annotation time but still get equally accurate results without the need to develop novel algorithms from scratch. [ABSTRACT FROM AUTHOR]

The question of why socially monogamous females engage in extra‐pair behaviour is long‐standing in evolutionary biology. Due to a lack of empirical support among passerine birds, recent work has moved away from the indirect‐benefits hypothesis to explain extra‐pair mating behaviour by females, instead favouring the hypothesis that this is the result of a pleiotropic effect. That is, a trait under strong positive selection in either or both sexes are genetically linked with another, potentially unrelated, trait. For example, genes beneficial to female fecundity (that promote within‐pair solicitation of mating from a male partner) might also lead to extra‐pair behaviour (by also promoting solicited copulations from extra‐pair males). Here, we test two predictions from this hypothesis: We test the prediction that female divorce, measured as the number of social mates within a given year, is linked with 1) the number of extra‐pair males engaged by the female and 2) the proportion of the female's offspring that are extra‐pair. Our results show that females who divorce their social partner are more likely to produce extra‐pair offspring than those who maintain social monogamy, supporting the pleiotropy hypothesis. However, those females did not also have a higher proportion of extra‐pair offspring. The number of broods initiated was also positively correlated with the number of extra‐pair males that sired a female's offspring, probably through increased opportunity for extra‐pair males to sire offspring over a longer breeding season. Our results support the intrasexual pleiotropy hypothesis as a driver of female extra‐pair behaviour. [ABSTRACT FROM AUTHOR]

To further elucidate the role that wear‐and‐tear plays in the transition from acute to chronic stress, we manipulated the intensity and duration of applied chronic stress to determine if behavior would respond proportionately. We brought wild house sparrows into captivity and subjected them to high‐stress, medium‐stress, low‐stress, or captivity‐only. We varied the number of stressors per day and the duration of stress periods to vary wear‐and‐tear, and thus the potential to exhibit chronic stress symptoms. The behaviors we assessed were neophobia (the fear of the new; assessed via food approach latency) and perch hopping (activity). We predicted that our birds would show proportionate decreases in neophobia and activity throughout a long‐term chronic stress paradigm. Our results indicate that neophobia is sensitive to the intensity of chronic stress, however, the birds became more neophobic, which was the opposite of what we expected. Conversely, perch hopping did not differ across treatment groups and is thus not sensitive to the intensity of chronic stress. Together, these data show that different behavioral measurements are impacted differently by chronic stress. Research highlights: We subjected house sparrows to different intensities of long‐term chronic stress and quantified behaviors. Neophobia differed across stress intensity groups but perch hopping did not, indicating that all behaviors do not respond to stress equally. [ABSTRACT FROM AUTHOR]

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]

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]

Simple Summary: Cities commonly support exotic species that can affect both wildlife and human health, but little is known regarding their distribution across the city and their relationship with socioeconomics. Here, we map the abundance of three non-native birds—domestic pigeon, house sparrow, and monk parakeet—in a Latin American city and investigate the effect of socioeconomics on their abundance. We found the domestic pigeon had a random spatial distribution across the city but reached its greatest abundance in low-income areas. The house sparrow was spatially aggregated in the southern and western areas of the city and reached its greatest abundance in low-income areas. The monk parakeet was spatially aggregated in the northeastern area of the city and reached its greatest abundance in high-income areas. Given that the abundance of non-native birds varies across the city and between socioeconomic groups, species-specific management is needed in different city zones to limit negative effects on native species and prevent human health risks. Cities commonly support a high abundance of non-native species that can affect both wildlife and human health; however, their distribution across the urban environment and their relationship with socioeconomics are not well documented. Here, we map the abundance of three non-native birds in a Latin American city—domestic pigeon (Columba livia f. domestica), house sparrow (Passer domesticus), and monk parakeet (Myiopsitta monachus)—and investigate the effect of socioeconomics on their abundance. We found that C. livia f. domestica exhibited a random distribution of abundance across the city but reached its greatest abundance in low-income areas. P. domesticus exhibited an aggregated distribution of abundance, being most abundant in the southern and western areas of the city and in low-income areas. M. monachus exhibited an aggregated distribution of abundance, being most abundant in the northeastern part of the city and reaching its greatest abundance in high-income areas. Low-income areas likely provide high abundance of food, shelter, and nesting sites for both C. livia f. domestica and P. domesticus, whereas high income areas have greater tree cover and larger trees in which M. monachus can build communal nests. Our study finds that the abundance of non-native birds varies across the city and between socioeconomic groups; therefore, targeted management is needed in different city zones to limit negative effects on native species and prevent zoonotic diseases. [ABSTRACT FROM AUTHOR]

The reactive scope model was created to address two major unanswered questions in stress physiology: how and when does the adaptive acute stress response turn into harmful chronic stress? Previous studies suggest that immunoenhancement should occur in reactive homeostasis (acute stress) and immunosuppression should occur in homeostatic overload (chronic stress). We used this dichotomy of immune function to further elucidate the transition from acute to chronic stress by treating house sparrows (Passer domesticus) with different intensities of chronic stress and then monitoring their immune function. By varying the number of stressors given per day and the length of chronic stress bouts over a period of 6 months, we produced four treatment groups: high, medium, and low stress, and captivity‐only. We tracked immunity through the bacterial killing assay and monitored healing of a 4 mm skin biopsy punch. We hypothesized that higher‐stress birds would repair their skin more slowly and have lower bacterial killing capacity. The opposite was true—high‐stress birds initially repaired their skin fastest. Additionally, all birds dramatically reduced bacterial killing capacity after the biopsy and increased food‐derived uric acid, suggesting increased energy acquisition and a shift in immune resources to a more immediate concern (healing). Once healing finished, only the high‐stress birds were unable to recover circulating immune function, suggesting that the combination of high stress and an immune challenge pushed these birds into homeostatic overload. Prioritizing healing over other immunological processes might be the best defense for a bird in its natural habitat. [ABSTRACT FROM AUTHOR]

Background: The House Sparrow (Passer domesticus L.), is a human-commensal bird species, belonging to the order Passeriformes. The rapid changes in our lifestyle resulted in the decrease of this bird population during the past four decades. Among the various causes viz., lack of food resources, pollution pressure, indiscriminate usage of pesticides etc. Habitat loss is found to be one of the main threats for their rapid decline. Installation of artificial nest boxes was found to be the best alternatives for raising the bird population. Methods: Jangareddigudem of West Godavari district, Andhra Pradesh, India, was chosen as the study area. The nest boxes were designed by incorporating certain modifications to the basic model specified by British Trust of Ornithology. Installation of the nest boxes was initiated from an area with moderate food resources, located towards south-west edge of the town and was expanded in to other areas in a latitudinal wise towards north and south directions. Data was collected on a regular basis to study the occupancy of the nest boxes by the house sparrows. Result: The model designed was proved to be protective from predators and also well accepted by the public. Out of 570 nests that were installed in the study area, 550 nests were occupied and being used for breeding, that comes to around 97.6% occupancy indicating the suitability and protectiveness of this model. The sparrow population in the study area has been increased with a count of sparrows from few to 300+ sparrows at each roosting site (two roosting sites) by the end of 2020 by utilizing the nest boxes. [ABSTRACT FROM AUTHOR]

House Sparrow is a widely distributed man-follower bird. This passerine bird is a secondary cavity-nesting bird. This species is habituated to live in human settlements, and confined to make nests in human habitations in available cavities, especially on the roofs of thatched and tiled roofed houses. Replacement of such traditional houses with RCC buildings leads to the unavailability of nesting sites causing the decline of the House Sparrow population. Our current study is aimed to observe the nesting behavior and breeding success in Open nests in the study area, Jangareddigudem. We observed and studied the influence of various factors on the breeding success of House Sparrows viz., the direction of the Open nest, height at which the nest is placed from the ground, location of the nest from the roof edge, location from vegetation, and light illumination at the nest. We have applied Chi-square tests to study the effect of said factors on the clutch size, hatching success, fledging success, and as a whole overall breeding success. The most influencing factors on the overall breeding success of House Sparrows were found to be the light illumination followed by direction, then far/depth from the roof edge, then vegetation, and finally height at which the nest is made from the ground. With respect to individual reproductive parameters, clutch size was found to be influenced by light illumination, and both hatching and fledging success were found to be influenced by the height of the nests from the ground. [ABSTRACT FROM AUTHOR]

Although stress can cause overall damage to the genome, it is currently unknown whether normal background damage to DNA varies throughout the annual cycle. If DNA damage did vary seasonally, it would have major implications on environmental‐genomic interactions. We measured background DNA double‐stranded breaks using the neutral comet assay in five tissues (nucleated red blood cells, abdominal fat, hippocampus, hypothalamus, and liver) in four cohorts of house sparrows (Passer domesticus): free‐living summer, captives on a summer light cycle, free‐living winter, and captives on a winter light cycle. The experiment was designed to answer three questions: (1) Is red blood cell DNA damage representative of other tissues? (2) Is DNA damage in captive birds representative of DNA damage in free‐living birds? (3) Does DNA damage show seasonality? We found that (1) blood is a representative tissue, (2) captive animals are representative of free‐living animals, and (3) DNA damage is higher in the summer than in the winter. These data indicate that red blood cells can be an index of DNA damage throughout the body and that background levels of DNA damage show substantial seasonal variation. The latter result suggests the possibility that underlying molecular mechanisms of DNA damage and/or repair also change seasonally. Research highlights: We measured double‐strand DNA breaks in five tissues across seasons and captivity states.All tissues show higher DNA damage in the summer than in the winter.The increase in DNA damage in the summer persists in captivity. [ABSTRACT FROM AUTHOR]

We discuss select imprecise and untenable natural history information about migration, urban habitat use, and diet presented in the technical literature about Accipiter hawks in North America. We focus primarily on challenging the claim that Sharp-shinned Hawks (Accipiter striatus) are more frequent predators of House Sparrows (Passer domesticus) than are Cooper's Hawks (A. cooperii). We urge scientists to be cognizant of the ever-changing dynamics of the predatory behavior, nesting, and migration ecology of Sharp-shinned and Cooper's hawks due to anthropogenic factors, features that are in constant flux and may not be well tracked long term or apply to the entire distributional ranges of these 2 species. Discutimos acerca de informaciones de historia natural imprecisa e insostenible acerca de la migración, del uso de hábitat urbano y la dieta presentada en la literatura técnica sobre gavilanes Accipiter en América del Norte. Principalmente nos enfocamos en cuestionar la afirmación de que el gavilán americano (Accipiter striatus) es un depredador más frecuente de gorrión común (Passer domesticus) que del gavilán de Cooper (A. cooperii). Exhortamos a los científicos a reconocer las dinámicas siempre cambiantes de comportamientos de depredación, anidamiento y ecología migratoria del gavilán americano y del gavilán de Cooper debido a factores antropogénicos, aspectos que están en flujo constante y podrían no tener buen seguimiento a largo plazo o no aplicar al rango de distribución completo de esas especies. Palabras clave: depredación, dieta, gorrión común, migración, urbanización. [ABSTRACT FROM AUTHOR]

House Sparrow (Passer domesticus) is a bird species connected to humans, widely distributed in most of the human settlements. They build nests in the crevices of our homes. The recent changes in house design minimized the crevices to build the nests and lead to habitat loss. The nest boxes are the alternative ways to re-establish the decreased House Sparrow population. We investigated the usage of nesting materials by House Sparrow with reference to construction of Open nests and Inbox nests in our study area. Because of its flexible attitude, it utilizes all the available materials for nest construction. In our study area at Jangareddigudem, we have examined about 100 Inbox nests and 40 Open nests. There are around 29 varieties of nesting materials used by Sparrows in the examined Inbox nests and around 27 varieties in the Open nests. Dūrvā grass found to be the major component of all the analyzed nesting materials in both Open and Inbox nests that constituted 43% and 36.5% respectively. The other structural materials such as coconut fibre (3.5%) and broom fibre (6%) were found to be more in Inbox nests. Synthetic fibre was more in Open nests (3.7%). We found significant differences between the Open and Inbox nests with respect to quantum of each nesting material type used, weight of the nests and time taken for nest construction by House Sparrow. [ABSTRACT FROM AUTHOR]

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]

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]

Animals are expected to select a breeding habitat using cues that should reflect, directly or not, the fitness outcome of the different habitat options. However, human-induced environmental changes can alter the relationships between habitat characteristics and their fitness consequences, leading to maladaptive habitat choices. The most severe case of such nonideal habitat selection is the ecological trap, which occurs when individuals prefer to settle in poor-quality habitats while better ones are available. Here, we studied the adaptiveness of nest box selection in a tree swallow (Tachycineta bicolor) population breeding over a 10-year period in a network of 400 nest boxes distributed along a gradient of agricultural intensification in southern Québec, Canada. We first examined the effects of multiple environmental and social habitat characteristics on nest box preference to identify potential settlement cues. We then assessed the links between those cues and habitat quality as defined by the reproductive performance of individuals that settled early or late in nest boxes. We found that tree swallows preferred nesting in open habitats with high cover of perennial forage crops, high spring insect biomass, and high density of house sparrows (Passer domesticus), their main competitors for nest sites. They also preferred nesting where the density of breeders and their mean number of fledglings during the previous year were high. However, we detected mismatches between preference and habitat quality for several environmental variables. The density of competitors and conspecific social information showed severe mismatches, as their relationships to preference and breeding success went in opposite direction under certain circumstances. Spring food availability and agricultural landscape context, while related to preferences, were not related to breeding success. Overall, our study emphasizes the complexity of habitat selection behavior and provides evidence that multiple mechanisms may potentially lead to an ecological trap in farmlands. [ABSTRACT FROM AUTHOR]

Dispersal has a crucial role determining ecoevolutionary dynamics through both gene flow and population size regulation. However, to study dispersal and its consequences, one must distinguish immigrants from residents. Dispersers can be identified using telemetry, capture‐mark‐recapture (CMR) methods, or genetic assignment methods. All of these methods have disadvantages, such as high costs and substantial field efforts needed for telemetry and CMR surveys, and adequate genetic distance required in genetic assignment. In this study, we used genome‐wide 200K Single Nucleotide Polymorphism data and two different genetic assignment approaches (GSI_SIM, Bayesian framework; BONE, network‐based estimation) to identify the dispersers in a house sparrow (Passer domesticus) metapopulation sampled over 16 years. Our results showed higher assignment accuracy with BONE. Hence, we proceeded to diagnose potential sources of errors in the assignment results from the BONE method due to variation in levels of interpopulation genetic differentiation, intrapopulation genetic variation and sample size. We show that assignment accuracy is high even at low levels of genetic differentiation and that it increases with the proportion of a population that has been sampled. Finally, we highlight that dispersal studies integrating both ecological and genetic data provide robust assessments of the dispersal patterns in natural populations. [ABSTRACT FROM AUTHOR]

Foraging animals usually select foods that balance the intake of key nutrients, for example essential amino acids that cannot be synthesized and must be obtained from the diet. However, the ability to gain optimal ratios, proportions and amounts of nutrients may be hampered by a changing environment, competitive conspecifics or species and predators. Here, we used an experimental system in which house sparrows, Passer domesticus , were fed a manipulated diet with different compositions of amino acids (in the experimental diet phenylalanine and tyrosine content was 42% of that in the control diet). Phenylalanine and tyrosine are precursors of coping hormones: dopamine, noradrenaline (norepinephrine) and adrenaline (epinephrine) which are involved mainly in the expression of stress and fear, but also in learning and long-term memory formation. Accordingly, birds fed a diet deficient in these amino acids learned to avoid unpalatable food markedly slower, coped worse with stress in the presence of a novel object and were more aggressive towards other sparrows than control birds. Surprisingly, circulating amounts of the catecholamines in blood plasma were higher in these birds than in sparrows on the control diet. This study provides the first evidence that variation in amino acid composition in the diet is associated with variation in behaviours and hormone levels in birds. We conclude that food, besides its nutritional function, seems to represent one of the modulators of behavioural expression making a balanced diet crucial for survival. • Animals balance the intake of key nutrients such as essential amino acids. • An imbalance of amino acids may result in behavioural changes. • Birds on an imbalanced diet learned slower and were more aggressive and stressed. • Food seems to represent one of the main modulators of behaviour. [ABSTRACT FROM AUTHOR]

Infrared thermography (IRT) is increasingly applied as a noninvasive technique for measuring surface body temperature changes related to physiological stress. As a basis for validation of IRT as a tool for diagnostic use, we need to assess its potential to measure hypothalamic-pituitary-adrenal (HPA) axis reactivity. We used experimental manipulations of the HPA axis in house sparrows (Passer domesticus), i.e. adrenal tissue responsiveness to exogenous adrenocorticotropin (ACTH) and the efficacy of negative feedback using the synthetic glucocorticoid dexamethasone (DEX), to test whether IRT is an effective tool for measuring HPA reactivity. Experimental birds showed a pronounced decrease in skin temperatures after ACTH injection and an increase in temperature after DEX injection. However, individual variation in glucocorticoid levels were not related to skin temperatures except after ACTH injection in experimental birds. We show that IRT can be used to measure HPA reactivity but that skin-temperature is not a good index for glucocorticoid secretion at baseline levels. These results suggest that while IRT of skin temperatures is a useful, noninvasive measure of HPA axis reactivity under acute activation, this technique might not be suitable for measuring natural variation of circulating glucocorticoid levels. [ABSTRACT FROM AUTHOR]

Cognitive flexibility may be necessary for animals facing changing conditions and has long been tested by the reversal learning paradigm. However, while this paradigm is typically based on training animals to discriminate between a rewarding and nonrewarding stimulus and then reversing their roles, under natural conditions animals usually face more than one set of two stimuli. Here, we addressed these potential intricacies by studying the reversal learning of house sparrows, Passer domesticus , in a two-set task. Sparrows previously trained as either colour or shape specialists exhibited different reversal dynamics: While colour discrimination was acquired faster than shape discrimination, shape specialists, including those reaching perfect preference of the rewarding shape, reversed faster than colour specialists. The reversal success of shape specialists was also less variable than that of colour specialists. Additionally, despite being slower, during the reversal, colour specialists sampled shapes more than shape specialists sampled colours. These results suggest that (1) when comparing different reversal tests, significant differences in reversal behaviour may be explained by the type of learned stimulus (e.g. shape versus colour) rather than by differences in cognitive flexibility and (2) under realistic conditions of multiple foraging options, preferences that are difficult to reverse (and typically viewed as indicating low cognitive flexibility) may nevertheless facilitate an ecologically flexible shift to novel food types. Finally, our results also demonstrate that a two-set (multiple-cue) experimental design may help to tease apart some of the different processes underlying reversal behaviour and cognitive flexibility. • The results of reversal learning tests differed depending on stimulus type. • Differences were independent of the discrimination level reached before reversal. • Associations that were difficult to reverse induced flexible shift to novel cues. • Reversal scores may not reflect ecological flexibility in multiple-cue environments. • A multiple-cue set-up helps tease apart the subcomponents of the reversal process. [ABSTRACT FROM AUTHOR]

The mechanisms that contribute to variation in lifetime reproductive success are not well understood. One possibility is that telomeres, conserved DNA sequences at chromosome ends that often shorten with age and stress exposures, may reflect differences in vital processes or influence fitness. Telomere length often predicts longevity, but longevity is only one component of fitness and little is known about how lifetime reproductive success is related to telomere dynamics in wild populations. We examined the relationships between telomere length beginning in early life, telomere loss into adulthood and lifetime reproductive success in free-living house sparrows (Passer domesticus). We found that females, but not males, with longer telomeres during early life had higher lifetime reproductive success, owing to associations with longevity and not reproduction per year or attempt. Telomeres decreased with age in both sexes, but telomere loss was not associated with lifetime reproductive success. In this species, telomeres may reflect differences in quality or condition rather than the pace of life, but only in females. Sexually discordant selection on telomeres is expected to influence the stability and maintenance of within population variation in telomere dynamics and suggests that any role telomeres play in mediating life-history trade-offs may be sex specific. [ABSTRACT FROM AUTHOR]

Telomeres, protective caps at the end of chromosomes, are often positively related to lifespan and are thought to be an important mechanism of organismal aging. To better understand the casual relationships between telomere length and longevity, it is essential to be able to experimentally manipulate telomere dynamics (length and loss rate). Previous studies suggest that exposure to TA‐65, an extract from the Chinese root Astragalus membranaceus, activates telomerase, lengthens telomeres, increases the growth of keratin‐based structures, and boosts the immune system in adults. However, telomere loss is expected to be greatest during early life but whether TA‐65 has similar effects during this life stage is currently unknown. Here, we experimentally exposed free‐living house sparrow (Passer domesticus) chicks to TA‐65 during post‐natal development and examined the effects on telomere length and loss, growth of keratin‐based structures, and a measure of cellular immunity. Contrary to expectation, the growth of keratin‐based structures was reduced in TA‐65 chicks and in the second year of the study, chicks exposed to TA‐65 experienced more telomere loss than controls. Thus, the effects of TA‐65 on telomeres and keratin‐based structures differ across life stages and future research will be necessary to determine the mechanisms underlying these age‐specific effects. Research Highlights: House sparrow chicks were exposed to TA‐65, an extract that increases telomere length in adulthood, to determine whether it also increases telomere length during post‐natal development. However, TA‐65 chicks do not experience less loss than controls. [ABSTRACT FROM AUTHOR]

Urbanization has a direct impact on avian communities as it modifies the landscape, consequently changing bird distribution, abundance and the resources on which avian populations depend. With increasing anthropocentric activities, there has been a marked decline in the urban population of house sparrows in Delhi, India. This study was undertaken to determine the impact of varying levels of urbanization (high-, medium- and low-density urban areas, suburban areas and agricultural areas) on the population and occupancy of sparrows. The encounter rate and occupancy probability were high in sub-urban and high-density urban areas, while they were low in lowdensity urban and agricultural areas. With active public participation, the sparrows can be conserved and their population can be re-established in areas where they have become extinct. [ABSTRACT FROM AUTHOR]

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]

Inbreeding may increase the extinction risk of small populations. Yet, studies using modern genomic tools to investigate inbreeding depression in nature have been limited to single populations, and little is known about the dynamics of inbreeding depression in subdivided populations over time. Natural populations often experience different environmental conditions and differ in demographic history and genetic composition, characteristics that can affect the severity of inbreeding depression. We utilized extensive long-term data on more than 3,100 individuals from eight islands in an insular house sparrow metapopulation to examine the generality of inbreeding effects. Using genomic estimates of realized inbreeding, we discovered that inbred individuals had lower survival probabilities and produced fewer recruiting offspring than noninbred individuals. Inbreeding depression, measured as the decline in fitness-related traits per unit inbreeding, did not vary appreciably among populations or with time. As a consequence, populations with more resident inbreeding (due to their demographic history) paid a higher total fitness cost, evidenced by a larger variance in fitness explained by inbreeding within these populations. Our results are in contrast to the idea that effects of inbreeding generally depend on ecological factors and genetic differences among populations, and expand the understanding of inbreeding depression in natural subdivided populations. [ABSTRACT FROM AUTHOR]

Invasive species are a threat to global biodiversity, yet the impacts of invasive birds on the native birds with which they compete are understudied. Humans have a long history of providing and managing nest boxes to support native birds; however, their management of non‐native birds has received limited research attention. We surveyed people who maintain nest boxes in North America to examine the extent of interference competition for nest sites between native and non‐native birds and the human behaviors intended to reduce nest site competition. Our specific objectives were to examine observations of nest usurpation of native birds by non‐native birds across the United States and Canada, to ascertain whether and how people who maintain nest boxes control non‐native bird species in favor of native species, and to quantify various factors correlated with the likelihood of engaging in management activities. We found that nearly one‐third of the 871 respondents had observed a non‐native species usurp a nest box occupied by a native species. Among respondents who reported nest usurpations, species‐specific nest usurpation rates varied (range = 3–35%). We found that witnessing a nest usurpation is the most important predictor of whether or not someone will engage in management activities. Management activity was also associated with the extent to which respondents believed non‐native birds to be a problem at the continental scale. Our study shows that people's observations of threats from introduced species are correlated with the environmental management actions people take, and that these actions can mitigate the threats, and potentially support the survival of native birds. [ABSTRACT FROM AUTHOR]

With changing urbanization pattern and architectural style, the house sparrow is rapidly losing its nesting ground leading to a drastic decline in its population. We studied the sparrow nest site selection to make recommendations to the Forest Department and NGOs in the conservation of sparrows in Delhi, India. Active nests were located across the habitat matrix in East Delhi. The maximum number of nests was found in suburban and high-density urban areas. The most preferred place for nesting was rolling shutters and wall crevices. The presence of old buildings, vegetation patch, water source, grocery shops, food provisioning, open drains and open dumps influence the sparrow nest selection site. By conserving natural habitat and installing nest boxes at suitable places, the sparrows can be conserved. [ABSTRACT FROM AUTHOR]

Anthropogenic noise pollution and the introduction of novel infrastructure can impose strong selective pressures on avian communication by affecting the efficacy with which acoustic signals are transmitted and received. Many species have now been shown to sing at higher frequencies in noisy urban environments. However, few studies have investigated the effects of signal modification on the response behaviours of receivers, and fewer still have been able to indicate the timescale over which these changes in pitch have occurred. We compare vocal communication between house sparrows Passer domesticus that reside within the world's largest, single‐span glasshouse (completed in the year 2000), and house sparrows directly outside this glasshouse, in open farmland. The glasshouse contrasts both acoustically and physically with the external environment, low frequency background noise being significantly louder inside than outside. We show that minimum song frequency was significantly higher inside the glasshouse than in surrounding farm habitat. Using song playback, we also found that birds within the glasshouse reacted more strongly to playbacks from the glasshouse habitat than they did to playback of song from farm birds outside. The degree of difference in frequency is similar to that shown for other bird species between urban and rural environments, demonstrating that such behavioural differences may arise over a relatively short time period (14 yr in this case). [ABSTRACT FROM AUTHOR]

According to the enemy release hypothesis (ERH) the spread of invasive species will be facilitated by release from their enemies as they occupy new areas. However, the ERH has rarely been tested by comparing populations of native (non-invasive, long established) species with expanding or shifting ranges, to the same species as invasive in another area. We tested the ERH with respect to blood parasite levels (prevalence and intensity of Plasmodium spp. and Haemoproteus spp.) of (a) two closely related, widely distributed species of thrush (Turdus leucomelas and T. merula), and (b) an invasive sparrow (Passer domesticus) whose range has expanded from the Old World to the New World since the 18th century. A total of 158 birds were sampled in Portugal and 99 in Brazil. All bird species were parasitized, and 55% of the individuals collected were parasitized, and the mean intensity of infection was of 28 parasites per 10,000 erythrocytes. We assessed whether differences in levels of infection (prevalence and intensity) were due to site (tropical/New World and temperate/Old World) or host species. The ERH was supported: Passer domesticus and Turdus merula had higher levels of parasitism in the Old World than in the New World. Thus, P. domesticus seems to be benefitting from its "recent" range expansion, compared to T. leucomelas, through ecological release from its native parasites and because the parasites of the recently invaded area seem to be infesting native species instead. [ABSTRACT FROM AUTHOR]

Highlights • Post-natal CORT levels were experimentally increased in wild sparrows. • Post-natal CORT treatment had no impact on the coloration of adult visual ornaments. • Post-natal CORT treatment resulted in smaller adult plumage-based signals. • Post-natal CORT exposure may affect sexual/hierarchical signals in adults. Abstract In vertebrates, the ontogeny of several crucial organismal systems is known to occur early in life. Developmental conditions can ultimately have important consequences on adult fitness by affecting individual phenotype. These developmental effects are thought to be primarily mediated by endocrine systems, and especially by glucocorticoids. In this study, we tested how post-natal exposure to corticosterone (the primary avian glucocorticoid) may subsequently affect the expression of ornaments in adult male house sparrows (Passer domesticus). Specifically, we investigated the long-term consequences of this manipulation on the size and color of several visual signals: badge, wing bar, tarsus and beak. Post-natal corticosterone exposure had a strong negative impact on the size, but not the color, of some male ornaments (badge and wing bar surface area). Because wing bar and badge surface area are used as sexual and/or hierarchical signals in house sparrow, we showed that early life stress can affect some aspect of attractiveness and social status in this species with potentially important fitness consequences (e.g. sexual selection and reproductive performance). Future studies need now to explore the costs and benefits of this developmental plasticity for individuals (i.e. fitness). [ABSTRACT FROM AUTHOR]

Summary: European starlings (Sturnus vulgaris), house sparrows (Passer domesticus) and rock pigeons (Columba livia) are all wild birds commonly found in large numbers in and around human dwellings and domestic livestock operations. This study evaluated the susceptibility of these species to three strains of highly pathogenic avian influenza virus (HP AIV) clade 2.3.4.4 isolated in the U.S.. Experimental infection of European starlings and rock pigeons did not result in any overt signs attributable to AIV infection and no virus shedding was detected from the oral and cloacal routes. House sparrows shed by the oral route and exhibited limited mortality. Individuals from all three species seroconverted following infection. These data suggest that none of these birds are a likely potential bridge host for future HP AIV outbreaks but that their seroconversion may be a useful surveillance tool for detection of circulating H5 HP AIV. [ABSTRACT FROM AUTHOR]

The ultimate goal of this study is to find out the most suitable combinations of adjacent crops that reduce house sparrows damage. The experiments were established using single and double combinations of four wintery crops. Namely, soft wheat, hard wheat, sunflower, and barley. The double cultivations were designed by growing varying crops nearby a fixed one crop as follows 1- (soft wheat alone), (soft wheat- near sunflower), ( soft wheat near – barley), and (soft wheat near – hard wheat) 2- (barley alone),(barley- near soft wheat), (barley near - hard wheat), and (barely- near sunflower) 3-(hard wheat alone),( hard wheat- near barley), (hard wheat near – sunflower), and ( hard wheat near – soft wheat). The experimental results revealed the following; the damage percentage of house sparrows to soft wheat was 25.9%, but when grown nearby sunflower, barley, and hard wheat the soft wheat damage reached 5.9%, 25.9%, and 33.3%, respectively. In single cultivation of barley, house sparrows damage was 8.2%, but when grown nearby soft wheat, hard wheat and sunflower, the barley damage reached 13.5%, 1.7% and 1.2%, respectively. Single cultivation of hard wheat house sparrows damage was 0.0%, while when grown adjacent to barley, sunflower, and soft wheat, the hard wheat damage reached 0.0%,0.0% 3.8%, respectively. In single cultivation of sunflower, house sparrows damage was 20.2%, while when grown nearby, barley, soft wheat, and hard wheat, the sunflower damage reached 9.5%, 10.2% and 36.3%, respectively. Results obtaine from this study revealed the following: 1- sunflower could be grown nearby barley and / or soft wheat, but away from hard wheat; 2- barley could be grown nearby sunflower and /or soft wheat, but away from hard wheat; 3- soft wheat could be grown nearby sunflower, but away from hard wheat; 4- hard wheat could be grown nearby barley or sunflower, but away from soft wheat. These concomitant cultivations can be successfully practiced be small growers to protect their main crops from house sparrows attack naturally and effectively without using any pest control compounds and without any extra costs as well. [ABSTRACT FROM AUTHOR]

Determining how an animal's social context alters its immune responses will help us understand how pathogens impact individual health and spread within groups. Several studies have shown that group-housed animals can suppress components of the acute phase immune response, specifically sickness behaviors like lethargy. However, we do not know whether individuals alter sickness behaviors or other components of the acute phase response, including thermoregulation, in response to the infection status of other group members. We used automated radio telemetry on captive house sparrows (Passer domesticus) to test whether sickness behaviors and thermoregulation differed during immune challenge under 2 social contexts: 1) all of the flock inoculated with lipopolysaccharide (LPS), a non-replicating component of gram-negative bacterial cell walls, or 2) half of the flock inoculated. We predicted that with half of the flock inoculated, LPS-treated birds would be under more pressure to maintain competitive behaviors, so would suppress components of the acute phase response. As we predicted, LPS-inoculated birds showed less pronounced heterothermia (fever) when housed with a mixture of inoculated and healthy flockmates. In contrast, LPS-inoculated birds exhibited similar degrees of lethargy regardless of the infection status of their flockmates. Our results show that the infection status of an individual's social group did exert an effect on the acute phase response but surprisingly did not impact the expression of lethargy, a canonical sickness behavior. Determining the mechanisms underlying these responses will require testing additional social contexts with different ratios of infected to uninfected birds. [ABSTRACT FROM AUTHOR]

Abstract In organisms, DDT (Dichlorodiphenyltrichloroethane) and its metabolites, DDE (Dichlorodiphenyldichloroethylene) and DDD (Dichlorobischlorophenylethane) are endocrine mimics. They can influence bone density and other bone structural features. This study was conducted on House Sparrows (Passer domesticus) caught from the Free State - and the Limpopo Provinces of South Africa (SA). The sites were chosen based on spraying patterns of DDT for malaria control or non-spraying. The bone mineral densities of the femurs as well as the lengths of the left- and right leg bones were determined using micro-focus X-ray computed tomography (μ-XCT). The concentrations of DDT and its metabolites in the liver were determined with gas-chromatography mass-spectrometry to provide baseline concentrations of DDT in the body, allowing comparison of the various groups of birds. There was no asymmetry between the lengths of the bones of the left- and the right legs. DDT concentrations in the liver did not correlate with bone lengths. In addition, there were no significant differences between the relative densities of the left- and right leg bones with increase of concentrations of DDT. The concentrations of DDT and its metabolites did not have a significant effect on the measured bone parameters of House Sparrows. It is possible that the concentrations of DDT and its metabolites in the environments were too low to be injurious to the birds and/or tolerance to the insecticide has developed in the birds over more than six decades of almost continuous application of DDT. Graphical abstract Image Highlights • Micro-XCT analysis for the examination of DDTs influence on bone features. • DDTs does not influence relative bone density of House Sparrows. • Asymmetry is not associated with environmental DDT exposure of House Sparrows. [ABSTRACT FROM AUTHOR]

The crop losses due to b,irds are serious and costly problem for farmers. The hooded crow (Corvus corone Linnaeus, 1758) and house sparrow (Passer domesticus niloticus Nicoll and Bonhote, 1909) are major pests for many crops in Egypt. In current work bird damage was assessed on maize, snake cucumber at El-Ibrahemia district, while that on pea and guava was determined at Zagazig district, Sharkia Goverenorate during the growing season 2016. Regarding maize, the hooded crow feed on developing ears in com fields following pollination and early in the grain filling period. The total number of inspected plants was 2800 and the highest losses (9 .81 % ) were recorded in the ih week. While, the hooded crow attacks snake cucumber fruits causing damage with mean percentage 6.33%. But the pea is preferable vegetable crop to birds, which destroy the leaves, flower bu(ls as well green seeds in pods and this damage may be reduced the yield. The average percentage of damage for pea was 4.41 %. The highest percentage of damage was 7.50% which obtained during the 5th week. Guava fruits were vulnerable to house sparrow, birds gnaw fruits. The losses by birds were estimated to be 4.79 and 4.64% in orchards nearby poultry farms and those nearby field crops, respectively. [ABSTRACT FROM AUTHOR]

The focus of the present study is to provide a full morphological description of the oropharyngeal cavity of the house sparrow. The head of six birds was prepared for gross examination and by stereo and electron microscopy. The bifid lingual apex has multiple long, rostrally directed needle-like processes. The lateral border of the apex carries rostromedially directed needle-like processes. The dorsal lingual surface of the apex and body carries numerous caudomedially directed filiform papillae and many orifices of lingual salivary glands. The lingual body is divided into two parts: rostral and caudal. The caudal part is divided into two laterally elevated regions by a median groove, while the rostral part is bounded laterally by a rostrodorsally directed papillary row, which on SEM is formed from two rows. On SEM, the lingual root has many orifices of posterior salivary glands. The pharyngeal papillary row is located at the caudal border of the laryngeal mound, but this single papillary row is formed from two rows at SEM magnification. The laryngeal cleft continues caudally as a laryngeal fissure bounded by two longitudinal rows of caudally directed papillae; at high SEM magnification, this fissure is divided into two halves by a median ridge which carries caudally directed papillae on its posterior part. The choanal cleft proceeds rostrally by the median tubercle. There are a small number of orifices of palatine salivary glands. The morphological characters of the oropharyngeal cavity of the sparrow confirm its adaptation to surrounding environmental conditions and available food particles. [ABSTRACT FROM AUTHOR]

The conditions of captivity can cause chronic stress in wild animals. Newly-captured animals may experience weight loss, elevated glucocorticoid hormones, increased heart rate, increased resting adrenomedullary activation, and an altered heart rate response to acute stressors. As captivity conditions persist, chronic stress may decrease as animals adjust to the stressors of captivity. In this study, house sparrows ( Passer domesticus ) were captured from the wild, fitted with heart rate transmitters in a minor surgical process, and individually housed in an indoor bird facility. Mass, baseline corticosterone, resting heart rate, resting adrenomedullary activation, and the acute heart rate response to a sudden noise were measured over the course of the first 6 weeks of captivity. Birds lost weight during the first weeks of captivity, which was regained by week 5. Baseline corticosterone peaked at day 7, decreased sharply by day 11, and continued to decrease throughout the 6 weeks. Although heart rate in the first 24 h could not be collected, daytime heart rate decreased from day 1 through day 20, where it reached a stable plateau. Daytime heart rate variability decreased through the entire 6 weeks, which may indicate a gradual shift from sympathetic to parasympathetic nervous system regulation of heart rate. The acute heart rate response to a sudden noise lasted longer at day 6 than earlier or later in captivity. In conclusion, the data indicate that the different physiological systems associated with chronic stress adjust to captivity over different timelines. [ABSTRACT FROM AUTHOR]

House and tree sparrows were common in cities and towns of the Lower Ob River basin down to the mouth in the 1970s-1980s. Currently, the house sparrow has spread in the localities of the middle and northern Yamal areas, whereas the tree sparrow has almost disappeared from the Lower Ob River basin. The house sparrow has moved to the Subarctic owing to the presence of localities with residential houses and warm shelters for vehicles and equipment, as well as houses near the oil and gas drill sites. This species reproduces during the same periods as in the temperate latitudes, annually brings two clutches, has an extended molting period, and migrates only in spring. The tree sparrow has similar ecological characteristics but prefers old wooden buildings. The southward shift of the distribution range of the tree sparrow is most likely associated with a decrease in the population. [ABSTRACT FROM AUTHOR]

Acute, short-term effects of early-life stress and associated glucocorticoid upregulation on physiology and survival are widely documented across vertebrates. However, the persistence and severity of these effects are largely unknown, especially through the adult stage and for natural systems. Here, we investigate physiological, morphological, and survival effects of post-natal glucocorticoid upregulation across the nestling, juvenile, and adult life stages in house sparrows ( Passer domesticus ). We manipulate circulating corticosterone concentration in wild, free-living house sparrow nestlings and monitor body size, size-corrected mass, two measures of health (hematocrit and phytohemagglutinin-induced skin swelling), and survival in a captive environment until adulthood. We find that early-life corticosterone exposure depresses nestling size-corrected mass in both sexes, with no strong effect of the treatment on body size or our two measures of health. Birds are able to compensate for negative effects of high early-life corticosterone exposure in the long-term and this effect largely disappears by the juvenile and adult stages. However, treatment has a negative effect on survival through one year of age, suggesting that long-term compensation comes at a price. [ABSTRACT FROM AUTHOR]

Studies using wild animals in laboratory-based research require bringing wild-captured organisms into a novel setting, which can have long-lasting impacts on physiology and behavior. In several species, captivity stimulates stress hormone production and can alter immune function. Despite this, there is little consensus on how captivity influences stress hormone regulation, or if captivity-induced changes in stress hormone production and regulation mediate changes in immune function. In this study, we investigate the influence of captivity on the physiology of a wild bird commonly-used in laboratory-based research, the house sparrow ( Passer domesticus ). We tested how captivity influences stress endocrinology, immune responses, and organ mass, and also investigated if the production or regulation of corticosterone, the main stress hormone in birds, correlated with changes in immunity. We found that baseline corticosterone concentrations and maximum capacity of the adrenals to secrete corticosterone increase following captivity and remain elevated after 9 weeks of captivity. A measure of innate immune function, the bactericidal ability of plasma, also increased with time spent in captivity. Wound healing was also influenced by time spent in captivity, with birds taking almost 2 days longer to heal if they were wounded after 3 weeks in captivity when compared with birds that were wounded immediately upon capture. Additionally, captivity caused notable reductions in spleen and liver mass. Together, these results imply that captivity can have long-lasting effects on house sparrow corticosterone release and immune function, and suggest that even after 9 weeks house sparrows do not acclimate physiologically to life in captivity. [ABSTRACT FROM AUTHOR]

In group-foraging species with no alarm signals, the sudden departure of neighbours can be used to inform the rest of the group about the detection of a threat. However, sudden departures are ambiguous because they can be triggered by factors unrelated to predator detection. We evaluated how animals react to the sudden departure of neighbours in groups of foraging house sparrows ( Passer domesticus). We focussed on false alarms that occurred for no apparent reasons to us because predation attempts were not frequent. Three factors can explain how the sudden departure of a neighbour can influence reaction times, namely group size, the distance between neighbours, and predation risk. We predicted reaction times to be longer in larger groups where individual vigilance levels are low, and when group members are further apart and cannot easily monitor each other. In addition, we expected reaction times to be longer when predation risk is lower. Departures that are more temporally clumped are also expected to be less ambiguous and should trigger faster reaction times. Our results show that sparrows reacted faster, not more slowly, to the sudden departures of neighbours in larger groups, and, as predicted, more slowly when neighbours were more distant from each other. Reaction times were longer in one of the two study years in which predation risk was deemed lower. Sparrows reacted more quickly when earlier departures were more temporally clumped. The results thus provided partial support for the predictions, and future work is needed to assess how individuals react to fleeing responses by their neighbours in species with no alarm signals. [ABSTRACT FROM AUTHOR]

The evolution of honest animal communication is mostly understood through the handicap principle, which is intrinsically dependent on the concept of individual quality: low-quality individuals are prevented from producing high-quality signals because, if they did so, they would pay greater production costs than high-quality individuals. We tested an alternative explanation for the black bib size of male house sparrows, Passer domesticus, an honest signal of quality the expression of which is negatively related to levels of the pigment pheomelanin in the constituent feathers. We previously showed that experimental depletion of cysteine, which participates in pheomelanogenesis, improves the phenotype (bibs larger than in controls) of high-quality males (birds with largest bibs initially) only. Here, we conducted an experiment under opposite conditions, increasing the availability of dietary cysteine, and obtained opposite results: deteriorated phenotypes (bibs smaller than in controls) were only expressed by high-quality birds. Some birds were also treated with the pro-oxidant diquat dibromide, and we found that the cellular resistance to free radicals of high-quality birds benefited more from the antioxidant activity of cysteine against diquat than that of lowquality birds. These findings support the existence of a mechanism uncoupling cysteine and pheomelanin in low-quality birds that confers on them a low sensitivity to variations in cysteine availability. This constitutes an explanation for the evolution of signal honesty that overcomes the limitations of the handicap principle, because it provides a specific definition of individual quality and because costs are no longer required to prevent low-quality individuals from producing large signals. [ABSTRACT FROM AUTHOR]

Bird feathers are commonly used to assess environmental contamination by chemical pollutants. However, although neonicotinoid insecticides are widely applied worldwide, feathers have rarely been used to survey the contamination by neonicotinoids in birds. To investigate whether clothianidin, one compound of the neonicotinoid class, is deposited into birds' feathers, we conducted an experiment with 56 wild male and female house sparrows dispatched in 7 aviaries. During this experiment, house sparrows were fed with certified organic seeds treated with clothianidin at an estimated concentration of 0.25 μg/g BW per day and per individual. We collected blood samples and plucked four tail feathers at the onset of the experiment to confirm that no birds were previously exposed to clothianidin. 35 days later, we collected blood samples and the newly grown feathers. Before exposure, a small number of birds showed very low clothianidin concentrations in plasma and feathers. After exposure, the plasma and the newly grown feathers of all birds contained clothianidin. Clothianidin concentrations in feathers were similar in both sexes, but the plasma of males contained clothianidin at higher concentrations than that of females. Our results confirm that ingested clothianidin transits in the plasma and is deposited in feathers during their growth. They also suggest substantial individual variation in the amounts of clothianidin transiting in the plasma and being deposited in feathers that may reflect variation in metabolism and/or access to food in relation to sex, social hierarchy and group dynamics. Whether increasing levels of exposure translate linearly or non-linearly (e.g. saturation process) into increasing clothianidin concentrations in bird plasma and feathers remains to be investigated. To conclude, these results confirm the relevance of using feathers to biomonitor the presence of neonicotinoids, but the relationship between the level of exposure and the concentrations found in feathers remains to be established. [Display omitted] • We investigated clothianidin deposition in feathers resulting from 5-week exposure. • 56 house sparrows fed with clothianidin treated seeds; 56 fed with untreated seeds. • Higher concentrations in male plasma; similar feather concentration in both sexes. • Presence of clothianidin in the environment reflected by deposition into feathers. • Relation between feather concentrations and level of exposure remains to be studied. [ABSTRACT FROM AUTHOR]

Reactive scope predicts that all animals have an adaptive ability to respond to stressors in their environment, termed reactive homeostasis, and that only when an animal’s response to stressful stimuli exceeds a certain threshold (homeostatic overload) will stress have pathological effects. While this framework has successfully helped interpret effects of stressors on wildlife, no study has designed an experiment to directly test this framework. This study was designed to expose house sparrows ( Passer domesticus ) to treatments that would result in varying ranges of reactive homeostasis during chronic stress, which based on the reactive scope model should cause birds with the lowest reactive homeostasis range to exhibit signs of pathology during a subsequent challenge. To modulate the reactive homeostasis range, we altered allostatic load of birds by exposing them to chronic stress while either elevating, blocking, or not manipulating corticosterone. After concluding chronic stress treatments, birds were exposed to the subsequent challenge of a superficial wound. Individuals treated with corticosterone during chronic stress (high allostatic load) experienced the most pathology, including both weight loss and slower wound healing. Unmanipulated birds (medium allostatic load) also experienced weight loss but had normal healing rates, while birds with blocked corticosterone (low allostatic load) had minimal weight loss and normal healing rates. Our results indicate that increased allostatic load reduces the reactive homeostasis range, thereby causing individuals to cross the homeostatic overload threshold sooner, and thus support the reactive scope framework. [ABSTRACT FROM AUTHOR]

The house sparrow (Passer domesticus) is a widely distributed bird species found throughout the world. Being a species which has close association with humans, they chiefly nest on man-made structures. Here we describe the materials used by the house sparrow for making nests along an urban to rural gradient. For the current study, we selected the Coimbatore to Anaikatty road (State Highway-164), a 27 km inter-state highway, which traverses along an urban core to rural outstretch of Coimbatore. Of the 30 nests observed, 15 nests were from the rural, 8 were from the suburban, and 7 were from the urban areas. The nests had two distinct layers, specifically the structural layer and the inner lining. In the current study, we identified 11 plant species, 2 types of animal matter, and 6 types of anthropogenic matter, including plastic pieces and fine rope. The amount of anthropogenic materials in the nest formation varied along the gradients. The usage of anthropogenic materials was high in urban areas (p<0.05) whereas it did not differ at the sub-urban regions (p>0.05). A gradual decrease in the usage of plant matter towards the urban area was noticed (p<0.05). This study explicitly documents the links between nest material usage along an urban to rural gradient, in a human associated bird. [ABSTRACT FROM AUTHOR]

Investigating factors which affect the decline in survival with age, i.e. actuarial senescence, is important in order to understand how demographic rates vary in wild populations. Although the evidence for the occurrence of actuarial senescence in wild populations is growing, very few studies have compared actuarial senescence rates between wild populations of the same species. We used data from a long-time study of demography of house sparrows ( Passer domesticus) to investigate differences in rates of actuarial senescence between habitats and sub-populations. We also investigated whether rates of actuarial senescence differed between males and females. We found that rates of actuarial senescence showed large spatial variation. We also found that the onset of actuarial senescence varied between sub-populations. However, these differences were not significantly explained by a general difference in habitat type. We also found no significant difference in actuarial senescence rates between males and females. This study shows that senescence rates in natural populations may vary significantly between sub-populations and that failing to account for such differences may give a biased estimate of senescence rates of a species. [ABSTRACT FROM AUTHOR]

Anthropogenic noise can have important physiological and behavioral effects on wild animals. For example, urban noise could lead to a state of chronic stress and could alter the development of the hypothalamus–pituitary–adrenal (HPA) axis. Supporting this hypothesis, several studies have found that human disturbance is associated with increased circulating corticosterone (CORT) levels. However, it remains unclear whether increased CORT levels are the result of anthropogenic noise or other anthropogenic factors. Here, we experimentally tested the impact of urban noise on the CORT stress response in an urban exploiter (the house sparrow, Passer domesticus ) by exposing chicks to a traffic noise (‘disturbed chicks’) or not (‘control chicks’). If noise exposure has a negative impact on developing chicks, we predicted that (1) disturbed chicks will grow slower, will be in poorer condition, and will have a lower fledging probability than controls; (2) disturbed chicks will have higher baseline CORT levels than control; (3) the CORT stress response will be affected by this noise exposure. Contrary to these predictions, we found no effect of our experiment on growth, body condition, and fledging success, suggesting that house sparrow chicks were not negatively affected by this noise exposure. Moreover, we did not find any effect of noise exposure on either baseline CORT levels or the CORT stress response of chicks. This suggests not only that house sparrow chicks did not perceive this noise as stressful, but also that the development of the HPA axis was not affected by such noise exposure. Our study suggests that, contrary to urban avoiders, urban exploiters might be relatively insensitive to urban noise during their development. Further comparative studies are now needed to understand whether such insensitivity to anthropogenic noise is a consistent phenomenon in urban exploiters and whether this is a major requirement of an urban way of life. [ABSTRACT FROM AUTHOR]

Many species show diet-induced flexibility of activity of intestinal enzymes; however, molecular and genetic mechanisms responsible for such modulation are less known, particularly in altricial birds. The goal of our study was to test whether a diet-induced increase in activity of intestinal maltase and sucrase in house sparrow nestlings is matched with an increase in maltase-glucoamylase ( MG) and sucrase-isomaltase ( SI) complex mRNAs respectively. Both enzyme activities were significantly higher in mid-intestine of nestlings fed a medium-starch ( MS) diet compared to those fed a starch-free ( SF) diet. In contrast to the similar pattern of dietary induction for both enzyme activities, diet MS elevated significantly only the level of MG mRNA, but not SI mRNA. The coordinated increase in activity of maltase and in MG mRNA is consistent with the hypothesis that dietary induction of this enzyme is under transcriptional control. In contrast, the lack of such coordination for changes in activity of sucrase and SI mRNA suggests that upregulation of this enzyme may be achieved by post-translational factor(s). We conclude that genetic mechanisms responsible for diet-induced flexibility of digestive enzymes in birds may differ from that observed in mammals. [ABSTRACT FROM AUTHOR]

Males that provide parental care may lose opportunities to acquire extrapair mates or secondary social mates. These opportunity costs can be estimated as the product of (1) the degree to which a male's participation in care makes him unready for mating (i.e. represents 'time-out' from the mating pool) and (2) the availability of potential mating partners. One stage of parenting may therefore be more costly than another because it depresses a male's probability of capitalizing on any given mating opportunity, and/or because it occurs when alternative mating opportunities are more abundant. To determine whether male parental care limits extrapair mating in house sparrows, Passer domesticus, we tracked changes in male extrapair mating success across stages of their nesting cycles. We then assessed whether periods of reduced extrapair mating by males coincided with a scarcity of fertilizable females, or whether certain activities placed males in time-out. We found that the number of potential extrapair mates was significantly higher on days when a male's social mate was fertile than during incubation or nestling provisioning; breeding synchrony consequently reduces the realized opportunity costs of male parenting. Nevertheless, males with nestlings to feed suffered greater opportunity costs than might be expected because of their relative inefficiency at obtaining extrapair matings with potentially available females. During the incubation stage, by contrast, the males' probability of extrapair mating per fertile female averaged four times higher. Thus, nestling provisioning apparently places males in a partial time-out, but male incubation does not. Males may be more fully engaged in the extrapair mating pool during incubation because they typically devote little time to this formof care and, when confronted with an increase in the abundance of extrapair mating prospects, they reduce the time they commit to incubation. [ABSTRACT FROM AUTHOR]