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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]

Agricultural intensification is a leading threat to bird conservation. Highly diversified farming systems that integrate livestock and crop production might promote a diversity of habitats useful to native birds foraging across otherwise‐simplified landscapes. At the same time, these features might be attractive to nonnative birds linked to a broad range of disservices to both crop and livestock production. We evaluated the influence of crop–livestock integration on wild bird richness and density along a north‐south transect spanning the U.S. West Coast. We surveyed birds on 52 farms that grew primarily mixed vegetables and fruits alone or integrated livestock into production. Crop–livestock systems harbored higher native bird density and richness relative to crop‐only farms, a benefit more pronounced on farms embedded in nonnatural landscapes. Crop–livestock systems bolstered native insectivores linked to the suppression of agricultural pest insects but did not bolster native granivores that may be more likely to damage crops. Crop–livestock systems also significantly increased the density of nonnative birds, primarily European Starlings (Sturnus vulgaris) and House Sparrows (Passer domesticus) that may compete with native birds for resources. Models supported a small, positive correlation between nonnative density and overall native bird density as well as between nonnative density and native granivore density. Relative to crop‐only farms, on average, crop–livestock systems exhibited 1.5 times higher patch richness, 2.4 times higher density of farm structures, 7.3 times smaller field sizes, 2.4 times greater integration of woody crops, and 5.3 times greater integration of pasture/hay habitat on farm. Wild birds may have responded to this habitat diversity and/or associated food resources. Individual farm factors had significantly lower predictive power than farming system alone (change in C statistic information criterion (ΔCIC) = 80.2), suggesting crop–livestock systems may impact wild birds through a suite of factors that change with system conversion. Collectively, our findings suggest that farms that integrate livestock and crop production can attract robust native bird communities, especially within landscapes devoted to intensified food production. However, additional work is needed to demonstrate persistent farm bird communities through time, ecophysiological benefits to birds foraging on these farms, and net effects of both native and nonnative wild birds in agroecosystems. [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 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]

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]

Wild animals living in proximity to humans may benefit from recognizing people individually and adjusting their behaviour to the potential risk or gain expected from each person. Although several urban-dwelling species exhibit such skills, it is unclear whether this is due to pre-existing advanced cognitive abilities of taxa predisposed for city life or arises specifically in urban populations either by selection or through ontogenetic changes facilitated by exposure to humans. To test these alternatives, we studied populations of house sparrows ( Passer domesticus) along the urbanization gradient. We manipulated the birds' experience (hostile or not) associated with humans with different faces (masks) and measured their behavioural responses to the proximity of each person. Contrary to our expectations, we found that while rural birds showed less fear of the non-hostile than of the hostile or an unfamiliar person, urban birds made no distinction. These results indicate that house sparrows are less able to recognize individual humans or less willing to behaviourally respond to them in more urbanized habitats with high human population density. We propose several mechanisms that may explain this difference, including reduced pay-off of discrimination due to a low chance of repeated interactions with city people, or a higher likelihood that city people will ignore them. [ABSTRACT FROM AUTHOR]

Birds use endogenous circadian clocks to regulate the wide array of functions. In the natural environment synchronized with day–night cycle, they exhibit these as daily rhythms in physiology and behavior. It is less understood, however, whether these daily rhythms have a seasonal perspective. We investigated this by measuring circadian clock governed activity behavior in House Sparrows (Passer domesticus) exposed to natural and artificial light–dark (LD) cycles at 27°N (Lucknow, India). Daily activity of Sparrows was recorded under natural daylight and temperature conditions (NDL) for ~11 months, beginning in late March. With more precise onsets than ends, Sparrows had varied daily activity pattern and duration between seasons. Further experiments investigated effect of seasons on circadian rhythm characteristics in Sparrows exposed to constant dim light (<1 lux) at different times of the year. The circadian rhythm period, activity pattern, and duration, but not the sensitivity of endogenous clock as shown by light-induced phase shifts, significantly varied over seasons. Also, resynchronization time (days) did not differ between seasons; although it was significantly longer to delay than to advance 6 h LD zeitgeber shifts. Thus, endogenous clock seems to closely correspond with environmental photoperiod in determining the daily activity behavior in House Sparrows. [ABSTRACT FROM AUTHOR]

Abstract: Temperate zone birds are highly seasonal in many aspects of their physiology. In mammals, but not in birds, the pineal gland is an important component regulating seasonal patterns of primary gonadal functions. Pineal melatonin in birds instead affects seasonal changes in brain song control structures, suggesting the pineal gland regulates seasonal song behavior. The present study tests the hypothesis that the pineal gland transduces photoperiodic information to the control of seasonal song behavior to synchronize this important behavior to the appropriate phenology. House sparrows, Passer domesticus, expressed a rich array of vocalizations ranging from calls to multisyllabic songs and motifs of songs that varied under a regimen of different photoperiodic conditions that were simulated at different times of year. Control (SHAM) birds exhibited increases in song behavior when they were experimentally transferred from short days, simulating winter, to equinoctial and long days, simulating summer, and decreased vocalization when they were transferred back to short days. When maintained in long days for longer periods, the birds became reproductively photorefractory as measured by the yellowing of the birds' bills; however, song behavior persisted in the SHAM birds, suggesting a dissociation of reproduction from the song functions. Pinealectomized (PINX) birds expressed larger, more rapid increases in daily vocal rate and song repertoire size than did the SHAM birds during the long summer days. These increases gradually declined upon the extension of the long days and did not respond to the transfer to short days as was observed in the SHAM birds, suggesting that the pineal gland conveys photoperiodic information to the vocal control system, which in turn regulates song behavior. [Copyright &y& Elsevier]

Male birds often possess conspicuous or colourful plumage traits which are thought to function either in mate choice or as status signals which indicate their competitive ability. Many studies have confirmed that the size or expression of these traits is positively correlated with their success at attracting mates, their social dominance, or their fitness. However, relatively few studies have examined plumage variation in females, likely because it is much less pronounced than in males. We examined whether female plumage is associated with fitness measures in the house sparrow ( Passer domesticus). Male house sparrows have a conspicuous throat patch of black feathers that has been correlated with social dominance and fitness, and females also possess a variably-coloured throat patch, although the variation is much more subtle than in males. However, neither the timing of breeding nor reproductive performance was associated with throat patch colouration of female sparrows in any of three continuous study years, nor was it related to female age. The size of the other obvious female plumage trait, the wing bar, also did not predict fitness. We conclude that female plumage variation is not under sexual selection in the house sparrow. [ABSTRACT FROM AUTHOR]

Abstract: Glucocorticoids (GCs) help individuals cope with changes throughout life; one such change is the seasonal transition through life-history stages. Previous research shows that many animals exhibit seasonal variation in baseline GCs and GC responses to stressors, but the effects of season on other aspects of GC regulation have been less studied. Moreover, whether elements of GC regulation covary within individuals and whether covariation changes seasonally has been not been investigated. Evolutionarily, strong linkages among GC regulatory elements is predicted to enhance system efficiency and regulation, however may reduce the plasticity necessary to ensure appropriate responses under varying conditions. Here, we measured corticosterone (CORT), the major avian GC, at baseline, after exposure to a restraint stressor, and in response to dexamethasone (to assess negative feedback capacity) in wild house sparrows (Passer domesticus) during the breeding and molting seasons. We also measured hippocampal mRNA expression of the two receptors primarily responsible for CORT regulation: the mineralocorticoid and glucocorticoid receptors (MR and GR, respectively). Consistent with previous studies, restraint-induced CORT was lower during molt than breeding, but negative-feedback was not influenced by season. Receptor gene expression was affected by season, however, as during breeding, the ratio of MR to GR expression was significantly lower than during molt. Furthermore, MR expression was negatively correlated with CORT released in response to a stressor, but only during molt. We found that individuals that most strongly up-regulated CORT in response to restraint were also most effective at reducing CORT via negative feedback; although these relationships were independent of season, they were stronger during molt. [Copyright &y& Elsevier]

Species that are introduced to novel environments can lose their native pathogens and parasites during the process of introduction. The escape from the negative effects associated with these natural enemies is commonly employed as an explanation for the success and expansion of invasive species, which is termed the enemy release hypothesis (ERH). In this study, nested PCR techniques and microscopy were used to determine the prevalence and intensity (respectively) of Plasmodium spp. and Haemoproteus spp. in introduced house sparrows and native urban birds of central Brazil. Generalized linear mixed models were fitted by Laplace approximation considering a binomial error distribution and logit link function. Location and species were considered as random effects and species categorization (native or non-indigenous) as fixed effects. We found that native birds from Brazil presented significantly higher parasite prevalence in accordance with the ERH. We also compared our data with the literature, and found that house sparrows native to Europe exhibited significantly higher parasite prevalence than introduced house sparrows from Brazil, which also supports the ERH. Therefore, it is possible that house sparrows from Brazil might have experienced a parasitic release during the process of introduction, which might also be related to a demographic release (e.g. release from the negative effects of parasites on host population dynamics). [ABSTRACT FROM AUTHOR]

Abstract: As cities expand worldwide, understanding how species adapt to novel urban habitats will become increasingly important to conservation. The adrenocortical stress response enables vertebrates to cope with novel environmental challenges to homeostasis. We examined total and estimates of free baseline and stress-induced corticosterone (CORT) concentrations and CORT binding globulin (CBG) levels in five passerine species within and around Phoenix, Arizona. We tested whether baseline and stress-induced CORT patterns differed among species living at varying densities in Phoenix and tested the hypothesis that, for species capable of successfully colonizing cities, individuals living in urban areas have a decreased acute stress response compared to individuals living in native desert. Baseline total CORT levels were generally similar in urban and rural birds. Capture and handling stress typically produced greater total CORT responses in urban birds than in rural birds, although these responses differed as a function of the life history stage (non-breeding, breeding or molt). CBG binding capacity did not change with life history stage or locality. Estimated free CORT concentrations differed less between groups than total CORT concentrations. Urban birds showed less variability in stress responses across life history stages than rural birds. We propose that more predictable resources in the city than in rural areas may decrease the need to vary stress responsiveness across life history stages. The results highlight the species-specific effects of urbanization on stress physiology and the difficulty to predict how urbanization impacts organisms. [Copyright &y& Elsevier]

The house sparrow Passer domesticus L. has become established and spread in almost all oceanic islands and continents, including northern Europe, during the last two centuries. This bird is a convenient subject to study the fate of parasites during the spread of their hosts to new geographical areas and ecosystems. We surveyed the house sparrow from St Petersburg Zoological Garden (36 birds) and from the village Rybachy on the Curonian Spit in the Baltic Sea (91 birds) during the breeding season in June and July 1996 and 2003, respectively. The birds were investigated by microscopic examination of blood films. The overall prevalence of blood parasites was 34%. Species of Plasmodium, Leucocytozoon, Isospora, Hepatozoon, and microfilariae were recorded. There was no significant difference in the prevalence of all infections between the two study sites. Haemoproteus spp. were not seen at either site. Species of Plasmodium were seen only in adult birds. Isospora adiei was significantly more prevalent in young than in adult birds. The results of this study are in accord with the literature data on the general pattern of distribution of blood parasites in the house sparrow in other parts of its extended range. It is probable that the spread of the house sparrow to new ecosystems contributes to the spread of I. adiei and Plasmodium spp., but not of Haemoproteus spp. The scarcity of Haemoproteus spp. infections in the house sparrow in northern Europe, North and South America, sub‐Saharan Africa, Australia, and oceanic islands show that this bird may be resistant to the majority of haemoproteids, which are common in the local avifauna. The application of molecular techniques is needed for understanding the phylogenetic relationships of blood parasites of the house sparrow and other birds. [ABSTRACT FROM AUTHOR]

Farmland bird species are particularly exposed to pesticides through various pathways. Among pesticides, neonicotinoids insecticides are commonly used in agriculture, but their influence on bird reproductive capacities is poorly understood. In this study, we experimentally tested the effects of the neonicotinoid acetamiprid on House sparrows' sperm quality and oxidative status following ingestion of a low and field-realistic dose of the compound. To do so, 56 males were captured, held and orally dosed seven times over 19 days of experiment with either a saline solution (control) or an acetamiprid-saline solution, and sperm samples were retrieved before and after the experiment. The overall dose given to the birds corresponded to 0.5% of the LD 50 for the Zebra finch (5.7 mg/kg BW) spread into 7 separate doses and administered every three days over the entire duration of the study (ca. 0.07% LD 50 per oral dose). Sperm mobility and sperm oxidative status were unaffected by the treatment, but sperm density was. Birds that received oral doses of acetamiprid suffered a significant decline in their sperm density compared to control birds. This result was confirmed by a significant decrease in the activity of the antioxidant enzyme SOD in the sperm of acetamiprid-dosed birds. These results provide the first evidence of sublethal toxicity of acetamiprid in a songbird and suggest that passerine birds' fertility may be negatively affected by very small doses of neonicotinoids in the wild. • We tested the effect of the neonicotinoid acetamiprid on sperm quality and sperm oxidative status in a passerine bird. • 56 wild male house sparrows were captured, held and orally dosed with acetamiprid or only the saline solution. • The acetamiprid dose corresponded to 0.5% of the LD 50 for zebra finches spread over the 19 experimental days. • Males that received acetamiprid suffered a 52% decline in their sperm density. [ABSTRACT FROM AUTHOR]

Many species of songbirds exhibit dramatic seasonal variation in song output. Recent evidence suggests that seasonal changes in auditory processing are coincident with seasonal variation in vocal output. Here, we show, for the first time, that frequency selectivity and temporal resolution of the songbird auditory periphery change seasonally and in a sex-specific manner. Male and female house sparrows (Passer domesticus) did not differ in their frequency sensitivity during the non-breeding season, nor did they differ in their temporal resolution. By contrast, female house sparrows showed enhanced frequency selectivity during the breeding season, which was matched by a concomitant reduction of temporal resolution. However, males failed to show seasonal plasticity in either of these auditory properties. We discuss potential mechanisms generating these seasonal patterns and the implications of sex-specific seasonal changes in auditory processing for vocal communication. [ABSTRACT FROM AUTHOR]