Search

A brief historical review is presented of the development of approaches to the study of the territorial space of songbirds (Oscines), using both older and current research methods. The study of bird territoriality has continued for more than a century, but there are still not only little-known aspects that remain in this direction, but also no consensus on terminology and methods. The description of the territorial space plays leading roles in such works. In turn, the classic objects of such research are songbirds demonstrating their territories by singing and defending them from invasion by other individuals. There have been many definitions proposed for the term "territory," which reflect different concepts of territoriality. The most common definition of a territory thereby is a defended (conceptually) and demonstrated (operationally) space. As a rule, this space is a certain area, a projection of the real territory to the surface on the ground. In recent decades, however, publications have appeared on the topic of exploring territories as three-dimensional (3D) structures. The most effective method of field registration of territories remains the territory mapping method based on visual observations of tagged individuals, which has also been adapted for 3D-territories. Alternative approaches to the registration of territories, including radio telemetry, have significant limitations. In terms of quantitative data-processing methods, there has been a shift over the past decades from an analysis of territories as polygons to their analysis as kernel isopleths. This approach allows for not only the territory contours to be understood, but also the frequency of the use of different points within its limits to be assessed. A significant achievement in recent years is the adaptation of the kernel methods to three-dimensional structures. It can be said that there is a need to study the territoriality of birds in the 3D-environment. Such research seems very promising because it can provide fundamentally new information on topics such as habitat selection and space use, the formation of the spatial and ethological structure of settlements, the separation of territories under high population densities and limited resources, and both intra- and interspecific competition. [ABSTRACT FROM AUTHOR]

Haemosporidians are common blood parasites in wild bird populations, yet their effects on oxidative status remain understudied. Here, we measured the levels of thiobarbituric acid-reactive substances (TBARS) as an indicator of reactive oxygen species (ROS), total antioxidant capacity (TAC) as an indicator of non-enzymatic molecular antioxidants, and TBARS/TAC ratio as an indicator of oxidative status. We also used parasite genus-specific primers and PCR techniques to detect haemosporidians in 117 adults of Rufous-collared Sparrow (Zonotrichia capensis) from four locations in south–central Chile. Mixed-effect models were employed to compare oxidative indicators between infected and uninfected birds. Infected birds showed significantly higher TBARS levels, but no significant differences in TAC, leading to a higher TBARS/TAC ratio, especially in reproductive individuals. This suggests increased oxidative damage in infected birds, irrespective of sex or body condition. A positive relationship between TBARS and TAC was observed in both groups, but the antioxidant response was weaker in infected birds, indicating differential oxidative stress responses based on infection status. Body condition did not differ significantly between infected and uninfected individuals. These results demonstrate that haemosporidian infections impose oxidative costs on birds, potentially compounding the oxidative costs associated with reproduction.

Many factors may affect the diversity and abundance of arthropods in their natural habitats including changes in temperature and humidity. Sometimes, large arthropods remain undetected in unsuspected habitats such as bird nests. Here, we explore the effects of an experiment modifying temperature and relative humidity inside the nest of a troglodyte bird species, the blue tit, Cyanistes caeruleus (L.) (Passeriformes: Paridae), on the abundance of dermestid beetles (Coleoptera: Dermestidae) inhabiting the nests. Ten taxa were identified, six at the species level and four—based on larval stages—at the genus level. Most of the dermestids found in the larval stage were nidicolous dermestids of the genus Anthrenus. Specimens of necrobiont dermestids (those that feed on carcasses in both the larval and adult stages) were found in lower numbers, and almost always in adult stages. The abundance of dermestid larvae found in blue tit nests where the temperature or the humidity were experimentally increased was significantly higher than in the control nests. In addition, adult necrobiont dermestids of genus Dermestes appeared more frequently in those nests where corpses of blue tit nestlings were found. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explored how blood parasites, known as haemosporidians, impact the oxidative status of Rufous-collared Sparrows, a common bird species in Chile. Oxidative status measures the balance between harmful molecules called reactive oxygen species (ROS) and the bird's ability to neutralize them with antioxidants. The study found that birds infected with haemosporidians had higher levels of ROS, indicating more oxidative stress than uninfected birds. While the overall antioxidant levels did not differ between infected and uninfected birds, the infected birds showed a greater imbalance in ROS/TAC, suggesting they suffered more oxidative damage. This was especially true for birds in their reproductive phase. These findings suggest that haemosporidian infection, combined with the demands of reproduction, may impose significant health costs on these birds. Understanding this could help us learn more about how infections affect wildlife, and the strategies parasites use to survive in their hosts. Haemosporidians are common blood parasites in wild bird populations, yet their effects on oxidative status remain understudied. Here, we measured the levels of thiobarbituric acid-reactive substances (TBARS) as an indicator of reactive oxygen species (ROS), total antioxidant capacity (TAC) as an indicator of non-enzymatic molecular antioxidants, and TBARS/TAC ratio as an indicator of oxidative status. We also used parasite genus-specific primers and PCR techniques to detect haemosporidians in 117 adults of Rufous-collared Sparrow (Zonotrichia capensis) from four locations in south–central Chile. Mixed-effect models were employed to compare oxidative indicators between infected and uninfected birds. Infected birds showed significantly higher TBARS levels, but no significant differences in TAC, leading to a higher TBARS/TAC ratio, especially in reproductive individuals. This suggests increased oxidative damage in infected birds, irrespective of sex or body condition. A positive relationship between TBARS and TAC was observed in both groups, but the antioxidant response was weaker in infected birds, indicating differential oxidative stress responses based on infection status. Body condition did not differ significantly between infected and uninfected individuals. These results demonstrate that haemosporidian infections impose oxidative costs on birds, potentially compounding the oxidative costs associated with reproduction. [ABSTRACT FROM AUTHOR]

In birds, extrapair paternity (EPP) constitutes an alternative mating strategy, with potentially important fitness consequences for both males and females and their offspring. Several factors have been identified that can influence the occurrence of EPP, but the role of environmental variability has so far received relatively little attention. Using long-term data set from a wild population of the blue tit (Cyanistes cearuleus), we assess the importance of ambient temperature in modulating the levels of extrapair paternity. Here, we showed that the variability of local thermal conditions affects the occurrence of EPP. Specifically, we found that the probability of EPP increased with rising variability in ambient temperature experienced by females prior to egg laying. This pattern is consistent with an idea of plastic female responses to unpredictable environments. Our results suggest that extrapair mating may represent an adaptive behavioral strategy to compensate for the potential negative effects of unstable environmental conditions. [ABSTRACT FROM AUTHOR]

The rules of song sequencing, i.e., the syntax, have been widely studied in many songbird species. However, individual and/or context-dependent variations in birdsong syntax are still poorly understood. Some information is available on this topic for species with complex songs. We studied the song syntax and its variability among individuals of the Siberian chiffchaff (Phylloscopus tristis), a species with a rather simple song. We analyzed the songs of 13 males. To analyze the song structure, we measured/calculated the song length, pause length, number of notes, and note types in each song, as well as the repertoire size for each individual. In order to analyze the organization of the song, we used Markov transitional matrices of different note types. Using these matrices, we calculated the note sequence linearity (SLIN) and consistency (SCONS) indexes, and the first-order relative entropy (RE1). Each male had a repertoire of 5–8 note types. Different males use the repertoire in different ways. Some of them arranged notes in the song in a strictly predictable way, while the note strings of the others could vary from song to song. We found that the song structure (i.e., song and pause lengths, number of notes and note types, and repertoire size) varied less strongly among individuals than the organization of the song (i.e., SLIN and RE1). We do not yet know if the variability in note sequencing is either an individual trait, or if it depends on the situation, or if is just a manifestation of random variations. [ABSTRACT FROM AUTHOR]

Nest location is one of the key components of avian reproduction and sharp transitions between different nest location strategies may have profound ecological and evolutionary consequences. Here, we used a phylogenetically‐informed comparative framework to reconstruct the evolution of ground nesting behaviour in passerine birds, quantify its biogeographical and habitat variation, and test for its associations with life history traits. Our dataset comprised over 1600 species distributed worldwide and representing ca 90% of all extant passerine families. Our analyses revealed a scattered phylogenetic distribution and moderate phylogenetic signal in the occurrence of ground nesting in passerines. We also found relatively high forward and backward transitions rates between character states of ground and non‐ground nesting, indicating strong evolutionary lability. Non‐ground nesting was identified as a likely ancestral state at the root of passerine phylogeny. Occurrence of ground nesting was clearly associated with habitat variation, as open habitats generally supported greater proportion of ground nesting species than non‐open habitats (forests). Within the major habitat categories we found greater proportion of ground nesters in boreal and temperate than subtropical and tropical zones. This reflected a general latitudinal gradient in the occurrence of ground nesting, with higher proportion of ground nesting species at higher latitudes (especially at the northern hemisphere). Ground nesting was also associated with fast life histories, as ground nesters had larger clutches, shorter incubation periods and faster chick development rates than non‐ground nesters. This variation was possibly driven by higher predation rates on nestlings and adult birds in ground nesting species. Our study lays a foundation for a comprehensive understanding of mechanisms and processes that have driven macroevolution of ground nesting behaviour in the most species‐rich extant avian lineage. [ABSTRACT FROM AUTHOR]

The present study investigates the occurrence and the identification of tick species infesting wild songbirds in northern Iran. During the period from 2015 to 2016, 342 songbirds belonging to 15 families and 37 species were captured and examined for tick infestation. Of which, 70 specimens were infested by ticks representing a 20.46% infestation rate. Four tick species detached from examined birds and identified as follow: Ixodes ricinus (Linnaeus, 1758), I. lividus Koch, 1844, Hyalomma sp., and Rhipicephalus sp. The most common one was I. ricinus. In all infected birds, collected ticks were in immature stages and the number of specimens of the larval stage was more than in the nymphal stage, and no adult tick was found. Following songbirds were introduced as new hosts: Rock Sparrow Petronia petronia (Linnaeus, 1766), Chestnut-shouldered Petronia Gymnoris xanthocollis (Burton, E, 1838), Eastern Olivaceous Warbler Hippolais pallida (Hemprich & Ehrenberg, 1833), Corn Bunting Emberiza calandra Linnaeus, 1758, Common Mynah Acridotheres tristis (Linnaeus, 1766), Eastern Pied Wheatear Oenanthe picata (Blyth, 1847), Pied Wheatear O. pleschanka (Lepechin, 1770), Desert Finch Rhodospiza obsoleta (Lichtenstein, MHC, 1823), Fire-fronted Serin Serinus pusillus (Pallas, 1811), and Red-breasted Flycatcher Ficedula parva (Bechstein, 1792) for I. ricinus.

Glucocorticoids are steroid hormones produced by the adrenal glands and released into the bloodstream in response to stressful situations. In birds, corticosterone (CORT) is the main glucocorticoid released under stress. Throughout their lives, animals in nature are continually exposed to noxious stimuli known as stressful events. Any alteration of homeostatic stability is a stressful situation and this alteration triggers physiological changes to restore homeostasis. Glucocorticoids are one of the components of the complex set of physiological and behavioral responses to stress. In this work, we use CORT supplied in drinking water to evaluate its effect in blood parameters and physiology in house sparrows (Passer domesticus). To accomplish this, P. domesticus were administered three different doses of CORT in drinking water for 72 h. Body mass, organ mass, pectoral muscle mass, leg muscle mass, and blood parameters (CORT, triglycerides, glucose and uric acid, heterophils/lymphocytes ratio, hematocrit, and serum protein profile) were determined before and after CORT treatment. A 15% decrease in body mass with a significant decrease in pectoral mass were observed after the higher CORT treatment, as well as a decrease in the plasma concentration of uric acid. Lastly, we found a reversal of the heterophils/lymphocytes ratio and a decrease in hematocrit. It was possible to establish first data for baseline and CORT‐alteration values in serum protein profile for P. domesticus. Baseline and altered values of blood parameters and serum protein profile could be an important tool in field ecology because they provide important data to assess the physiological condition in wild birds. Highlights: We use corticosterone supplied in drinking water as a model to determine its effect on blood parameter levels and physiological alterations in house sparrows (Passer domesticus).Body mass alterations with a significant pectoral mass decrease were observed after the treatment, as well as variations in the plasma concentration of uric acid (UA), heterophils/lymphocytes (H/L) index, and hematocrit. But we did not found an effect on triglycerides (TG), glucose, and δ‐aminolevulinic acid dehydrogenase activity.Alterations in the electrophoretic profile of serum protein values were observed in house sparrows exposed to high concentrations of corticosterone.Baseline and altered values of blood parameters and serum proteins profile could be an important tool in field ecology because they provide important data to assess the physiological condition in wild birds. [ABSTRACT FROM AUTHOR]

Mobbing is a prey antipredator behaviour aimed to reduce the risk of predation. The behaviour may be innate and/or learned. Evaluating this behaviour on a large spatial scale can help to explore the mechanisms behind it. Using a playback experiment, I investigated variation in antipredator behaviour in small passerines in response to vocalisation from a potential predator, Eurasian pygmy owl (Glaucidium passerinum), at 105 sites in 35 localities within and outside the owl's breeding range. While the birds outside the owl's breeding range did not respond to the owl's call, they mobbed at about 60% of the sites within the owl's breeding range. At sites where the birds did not respond to the owl presentation, alarm calls of forest passerines were broadcasted to them. The birds always mobbed in response to the playback of these alarm calls. These results indicate that the birds' response to the owl call may be a plastic trait induced by learning, while the response to the alarm calls of birds may be innate, as predation pressure in general can be strong enough to cause directional selection on the prey's response to the alarm signalling of other birds. [ABSTRACT FROM AUTHOR]

Climate change, specifically rising temperatures and increased frequency of droughts will increase the level of exposure of organisms to chemical pollution. Notably, the impact of increased frequency and duration of drought events and subsequent dehydration on pesticide toxicity remains largely unknown. We evaluated the combined effects of exposure to the pesticide Chlorpyrifos (CPF) and water restriction (WR) on the enzymatic activities of three plasma esterases (acetylcholinesterase, butyrylcholinesterase and carboxylesterase), basal metabolic rate (BMR), leukocyte profile (proportion of heterophils to lymphocytes; H:L ratio), and bactericidal capacity of plasma in the rufous-collared sparrow (Zonotrichia capensis), a common passerine bird in Chile. The activity of the enzyme carboxylesterase decreased in birds exposed only to CPF and birds exposed to both the CPF and WR. In the group exposed to both stressors, the butyrylcholinesterase activity was also reduced. The BMR exhibited an increase in both groups exposed to CPF, with a higher rise observed in the group exposed to both CPF and WR, while the group subjected to WR showed no change. The bactericidal capacity of the plasma decreased significantly in birds exposed to CPF and in those exposed to both the pesticide and WR, while a marginal effect was observed in the group only subjected to WR. The H:L ratio increased in all groups, with the most pronounced effect in birds exposed to both stressors. These results suggest a shift in the energy budget of Z. capensis , favoring the detoxification of the pesticide through esterase activities, at the expense of reduced immunocompetence. [Display omitted] • The combined effect of pesticide Chlorpyrifos and water restriction were tested on the songbird, Zonotrichia capensis. • Detoxification enzyme activities decreased significantly under combined CPF exposure and water restriction. • Basal metabolic rate increased in response to both stressors, highlighting elevated energy demands. • Immune function was severely compromised, with a marked increase in stress indicators and reduced bactericidal capacity. [ABSTRACT FROM AUTHOR]

Multiple factors influence predation risk, ranging from habitat conditions to the composition and behaviour of predators. Although these factors are well documented for forest ecosystems, there is little evidence for wetlands, especially within Patagonia. Using artificial nests and camera traps, we documented the nest predation rates and predator assemblage of birds nesting in wetlands of the Patagonian steppe. We also determined the effect of vegetation cover on nest survival and studied the variation in predator groups according to nest placement: nests located in an open wetland, peripheral grassland to the wetland, and nests located in shrubs at different heights. We found 84% of nests failed, counting birds, mice, and armadillos as the main predators. Vegetation cover affected predation events of birds and small mammals, but not those of larger mammals. In turn, small mammals preyed on nests exclusively located in peripheral grassland, medium mammals preferred nests placed in open wetlands, and predation by birds was irrespective of open wetlands and grassland. We also found differences in nest predator assemblage between nests placed on the ground and in shrubs, with birds being the main predators of nests located above ground. These results can be attributed to differential habitat use and movement patterns specific to each predator group. Therefore, the identity, density, and behaviour of predators should be taken into account when planning conservation strategies for birds breeding in wetlands. [ABSTRACT FROM AUTHOR]

Tropical islands are renowned as natural laboratories for evolutionary study. Lineage radiations across tropical archipelagos are ideal systems for investigating how colonization, speciation, and extinction processes shape biodiversity patterns. The expansion of the island thrush across the Indo-Pacific represents one of the largest yet most perplexing island radiations of any songbird species. The island thrush exhibits a complex mosaic of pronounced plumage variation across its range and is arguably the world's most polytypic bird. It is a sedentary species largely restricted to mountain forests, yet it has colonized a vast island region spanning a quarter of the globe. We conducted a comprehensive sampling of island thrush populations and obtained genome-wide SNP data, which we used to reconstruct its phylogeny, population structure, gene flow, and demographic history. The island thrush evolved from migratory Palearctic ancestors and radiated explosively across the Indo-Pacific during the Pleistocene, with numerous instances of gene flow between populations. Its bewildering plumage variation masks a biogeographically intuitive stepping stone colonization path from the Philippines through the Greater Sundas, Wallacea, and New Guinea to Polynesia. The island thrush's success in colonizing Indo-Pacific mountains can be understood in light of its ancestral mobility and adaptation to cool climates; however, shifts in elevational range, degree of plumage variation and apparent dispersal rates in the eastern part of its range raise further intriguing questions about its biology. [ABSTRACT FROM AUTHOR]

Introduction: Decreasing biotic diversity with increasing latitude is an almost universal macroecological pattern documented for a broad range of taxa, however, there have been few studies focused on changes in gut microbiota (GM) across climatic zones. Methods: Using 16S rRNA amplicon profiling, we analyzed GM variation between temperate (Czechia) and tropical (Cameroon) populations of 99 passerine bird species and assessed GM similarity of temperate species migrating to tropical regions with that of residents/short-distance migrants and tropical residents. Our study also considered the possible influence of diet on GM. Results: We observed no consistent GM diversity differences between tropical and temperate species. In the tropics, GM composition varied substantially between dry and rainy seasons and only a few taxa exhibited consistent differential abundance between tropical and temperate zones, irrespective of migration behavior and seasonal GM changes. During the breeding season, trans-Saharan migrant GM diverged little from species not overwintering in the tropics and did not show higher similarity to tropical passerines than temperate residents/short-distance migrants. Interestingly, GM of two temperate-breeding trans-Saharan migrants sampled in the tropical zone matched that of tropical residents and converged with other temperate species during the breeding season. Diet had a slight effect on GM composition of tropical species, but no effect on GM of temperate hosts. Discussion: Consequently, our results demonstrate extensive passerine GM plasticity, the dominant role of environmental factors in its composition and limited effect of diet. [ABSTRACT FROM AUTHOR]

IntroductionDecreasing biotic diversity with increasing latitude is an almost universal macroecological pattern documented for a broad range of taxa, however, there have been few studies focused on changes in gut microbiota (GM) across climatic zones.MethodsUsing 16S rRNA amplicon profiling, we analyzed GM variation between temperate (Czechia) and tropical (Cameroon) populations of 99 passerine bird species and assessed GM similarity of temperate species migrating to tropical regions with that of residents/short-distance migrants and tropical residents. Our study also considered the possible influence of diet on GM.ResultsWe observed no consistent GM diversity differences between tropical and temperate species. In the tropics, GM composition varied substantially between dry and rainy seasons and only a few taxa exhibited consistent differential abundance between tropical and temperate zones, irrespective of migration behavior and seasonal GM changes. During the breeding season, trans-Saharan migrant GM diverged little from species not overwintering in the tropics and did not show higher similarity to tropical passerines than temperate residents/short-distance migrants. Interestingly, GM of two temperate-breeding trans-Saharan migrants sampled in the tropical zone matched that of tropical residents and converged with other temperate species during the breeding season. Diet had a slight effect on GM composition of tropical species, but no effect on GM of temperate hosts.DiscussionConsequently, our results demonstrate extensive passerine GM plasticity, the dominant role of environmental factors in its composition and limited effect of diet.

The present study investigates the occurrence and the identification of tick species infesting wild songbirds in northern Iran. Totally, 342 songbirds belonging to 15 families and 37 species were captured and examined for tick infestation during 2015-2016. Of which, 70 specimens were infested by ticks (infestation rate = 20.46%). Three tick species detached from examined birds and identified as follow: Ixodes ricinus (Linnaeus, 1758), Hyalomma sp., and Rhipicephalus sp. The most common one was I. ricinus. In all infected birds, collected ticks were in immature stages and the number of specimens of the larval stage was more than in the nymphal stage, and no adult tick was found. Following songbirds were introduced as new hosts: Petronia petronia (Linnaeus, 1766), Gymnoris xanthocollis (Burton, E, 1838), Hippolais pallida (Hemprich & Ehrenberg, 1833), Emberiza calandra Linnaeus, 1758, Acridotheres tristis (Linnaeus, 1766), Oenanthe picata (Blyth, 1847), O. pleschanka (Lepechin, 1770), Rhodospiza obsoleta (Lichtenstein, MHC, 1823), Serinus pusillus (Pallas, 1811), and Ficedula parva (Bechstein, 1792) for I. ricinus. The overall mean intensity and mean abundance were 4.6 and 0.95, respectively. The highest mean intensity, 12.18 ticks per bird, was recorded from Common Starling. The highest prevalence of infestation was recorded on Common Blackbird (53%). The most prevalence of tick infestation occurred in the Turdidae family (37.83%) followed by Passeridae (33.33%) and Sturnidae (28.57%). [ABSTRACT FROM AUTHOR]

Twenty-one white-rumped shamas (19 necropsied, 2 biopsied) (Copsychus malabaricus) housed at the San Diego Zoo between 1992 and 2020 were diagnosed with Isospora infection based on evaluation of histologic sections. Review of these cases revealed a consistent histologic lesion characterized by nodular aggregates of atypical epithelioid macrophages containing few intracytoplasmic protozoa, with or without lymphocytic infiltrates. Of the 19 necropsied cases, 16 (84%) had systemic lesions variably affecting the liver, spleen, gastrointestinal tract, lung, pancreas, connective tissues, or bone marrow, while all 21 diagnosed cases had skin involvement. The findings suggest that white-rumped shamas have a unique inflammatory response to isosporosis with a predilection for the skin. Skin may be a diagnostically sensitive sampling site for histologic diagnosis of Isospora in this species. [ABSTRACT FROM AUTHOR]

Rhodopsin is the visual pigment responsible for initiating the phototransduction cascade in vertebrate rod photoreceptors. Although well-characterized in a few model systems, comparative studies of rhodopsin function, particularly for nonmammalian vertebrates are comparatively lacking. Bowerbirds are rare among passerines in possessing a key substitution, D83N, at a site that is otherwise highly conserved among G protein-coupled receptors. While this substitution is present in some dim-light adapted vertebrates, often accompanying another unusual substitution, A292S, its functional relevance in birds is uncertain. To investigate functional effects associated with these two substitutions, we use the rhodopsin gene from the great bowerbird (Ptilonorhynchus nuchalis) as a background for site-directed mutagenesis, in vitro expression and functional characterization. We also mutated these sites in two additional rhodopsins that do not naturally possess N83, chicken and bovine, for comparison. Both sites were found to contribute to spectral blue-shifts, but had opposing effects on kinetic rates. Substitutions at site 83 were found to primarily affect the kinetics of light-activated rhodopsin, while substitutions at site 292 had a larger impact on spectral tuning. The contribution of substitutions at site 83 to spectral tuning in particular depended on genetic background, but overall, the effects of substitutions were otherwise surprisingly additive, and the magnitudes of functional shifts were roughly similar across all three genetic backgrounds. By employing a comparative approach with multiple species, our study provides new insight into the joint impact of sites 83 and 292 on rhodopsin structure-function as well as their evolutionary significance for dim-light vision across vertebrates.

Success in egg incubation and chick rearing in 18 passerine bird species has been analyzed based on the results of observations on the survival of 12 610 eggs in 2083 nests found in the Ob forest tundra and the southern, central, and northern Yamal peninsula. It has been found that a northward increase in nest success is observed in the direction from the Southern Urals and Kazakhstan to Yamal but not from the Baltic Sea to Yamal. In the total forest tundra–subarctic tundra space, nest success increases to the north in one group of species (the common redpoll, Lapland longspur, and common chiffchaff) but decreases in another group (the horned lark, red-throated pipit, bluethroat, and willow warbler). [ABSTRACT FROM AUTHOR]

Migratory birds play an important role in large-scale movements of ticks and tick-borne pathogens, yet little is known about tick infestation of resident birds (e.g., non-migratory species and migratory species during the breeding season), especially in urban ecosystems. We captured birds during the breeding season in parks and greenspaces in Oklahoma City, Oklahoma, USA, to evaluate overall tick infestation patterns and to determine if urbanization influences infestation prevalence (the proportion of birds parasitized) and intensity (the number of ticks on infested birds). Of 459 birds, 111 (24.2%) had ≥ 1 tick, a high proportion of infestation compared with past North American studies. The most frequently infested species were Carolina Wren (Thryothorus ludovicianus; 56%), Brown Thrasher (Toxostoma rufum; 37%), and Northern Cardinal (Cardinalis cardinalis; 27%). The Lone Star Tick (Amblyomma americanum) comprised half (51%; n = 322) of all ticks on birds; other species sampled included Gulf Coast Tick (A. maculatum) (36%) and Rabbit Tick (Haemaphysalis leporispalustris) (13%). Urbanization intensity (i.e., the percentage of developed land around sites) was inversely related to infestation prevalence for all birds combined and for Carolina Wren, but intensity of infestation was unrelated to urbanization. Our results suggest that non-migratory and migratory birds during sedentary periods are important carriers of ticks in urban areas, and that tick infestation patterns can be influenced by the level of urbanization in the surrounding landscape. Clarifying how urban birds influence tick populations, and how urbanization shapes bird-tick interactions, will increase understanding of tick-borne disease ecology in urban ecosystems. [ABSTRACT FROM AUTHOR]

Genetic diversity is one of the three dimensions of biodiversity and fundamental to various life forms on the Earth. Understanding the distribution pattern of genetic diversity and its driving forces has been an important topic in ecology, biogeography and conservation biology since the last decade. We investigated the genetic diversity pattern of passerine birds in the Mountains of Southwest China, a global biodiversity hotspot with the highest species richness of birds in the entire Eurasia, and explored the influencing forces of environmental variables on genetic diversity. We compiled 1189 Cytochrome b sequences of 27 passerine species from 152 geographic sites, covering the range of Mountains of Southwest China and its adjoining areas. We generated genetic diversity distribution maps using a grid-cell method based on nucleotide diversity and haplotype diversity indices. We further analyzed the variation pattern of the two indices along latitudinal, longitudinal, and elevational gradients. The correlations between the two indices and environmental variables were also evaluated. The nucleotide diversity hotspots were mostly located in the southern Hengduan Mountains, while for haplotype diversity, three hotspots were detected: the southeast edge of the Qinghai-Tibetan Plateau, the southern Hengduan Mountains and the Qinling Mountains. There was no monotonic increasing or decreasing pattern in nucleotide diversity or haplotype diversity along latitudinal, longitudinal or elevational gradients except for altitudinal range. Correlation and model selection analyses detected multiple environmental variables in driving genetic diversity patterns, including temperature, precipitation, vegetation, human influence, longitude and altitude range. Similar to the pattern of species richness, the nucleotide diversity pattern of passerine birds in the Mountains of Southwest China presents a decreasing trend from southwest to northeast, while the haplotype diversity pattern is more likely decreased from west to east. Our results indicate that the distribution pattern of genetic diversity may be derived from the complex topography and diverse microclimates in the Mountains of Southwest China.

While seasonal trends in testosterone levels are known from cross-cohort studies, data on testosterone inter-annual individual repeatability in wild birds are rare. Also, our understanding of hormonal age-dependent changes in testosterone levels is limited. We assessed plasma testosterone levels in 105 samples originating from 49 repeatedly captured free-living great tits (Parus major) sampled during the nesting to investigate their relative long-term repeatability and within-individual changes. Furthermore, we examined the inter-annual repeatability of condition-related traits (carotenoid- and melanin-based plumage ornamentation, ptilochronological feather growth rate, body mass, and haematological heterophil/lymphocyte ratio) and their relationships to testosterone levels. We show that testosterone levels are inter-annually repeatable in females, with a non-significant pattern in males, both in absolute values and individual ranks (indicating the maintenance of relative status in a population). In males, we found a quadratic dependence of testosterone levels on age, with a peak in midlife. In contrast, female testosterone levels showed no age-dependent trends. The inter-annual repeatability of condition-related traits ranged from zero to moderate and was mostly unrelated to plasma testosterone concentrations. However, males with elevated testosterone had significantly higher carotenoid-pigmented yellow plumage brightness, a trait presumably involved in mating. Showing inter-annual repeatability in testosterone levels, this research opens the way to further understanding the causes of variation in condition-related traits. Based on a longitudinal dataset, this study demonstrates that male plasma testosterone undergoes age-related changes that may regulate resource allocation. Our results thus suggest that, unlike females, male birds undergo hormonal senescence similar to mammals. [ABSTRACT FROM AUTHOR]

Abstract Parental care in birds varies among species and geographic regions. Incubation behavior influences embryonic development rate and varies substantially among species. We studied attendance at the nest by videoing nests or collecting data from the literature for 112 species in north temperate and lowland tropical sites, then associated patterns of incubation on‐ and off‐bouts with species and environmental traits. Songbirds nesting at low elevations incubate their eggs for an average of 74.1% (±12.9 SD, n = 60 species) of the time in temperate regions and 71.0% (±12.2 SD, n = 52 species) in tropical regions during daylight hours, and 84.3% (±8.2 SD) and 85.3% (±6.2 SD), respectively, of each 24‐hr cycle. While these attendance percentages do not differ significantly between latitudes, our data also show that lowland tropical songbirds make fewer visits to the nest and, consequently, have longer on‐bouts and off‐bouts during incubation. This pattern in attendance reflects a latitudinal contrast in parental care strategy, where lowland tropical birds reduce visits to the nest by increasing on‐ and off‐bout lengths while maintaining the same proportion of time spent incubating their eggs (constancy). Similar constancy across latitude suggests that tropical and temperate birds may be similarly constrained to maintain elevated egg temperatures for normal embryo growth. The different attendance strategies adopted in each region may reflect differences in ambient temperature, adult foraging time, and nest predation rate. Consistently warm ambient temperatures likely allow tropical birds to take longer off‐bouts, and thereby to reduce activity around the nest, compared to temperate birds.

Objective of research: The study of the influence of the host sex on helminth community structure in passerine birds. Material and methods: 230 individuals of both sex of 6 bird species from order Passeriformes (tree pipit, red-backed shrike, great tit, Eurasian tree sparrow, common chaffinch, yellowhammer) were examined by a method of incomplete helminthological dissection. Parasitological monitoring was conducted by standard methods. Statistical processing of data was carried out using the Shannon, Jaccard, Sorensen indices, Kovnatsky index of domination and Mann-Whitney U test. Results and discussion: The influence of sex structure of host population on the helminth communities of passerine birds was studied. 26 parasite species were registered. Large species diversity was found in helminth communities of yellowhammer and great tit males; in common chaffinch - of females. No difference was detected in parasite communities of males and females of tree pipit and red-backed shrike. Only males of Eurasian tree sparrow were infected. Parasite communities in males and females of tree pipit, yellowhammer and red-backed shrike are most similar. The minimum similarity was found between parasite communities of common chaffinch of both sexes. Neither the analysis of infestation of males and females by individual helminth species nor of the aggregate helminth infestation of both sexes of each bird species, has revealed a universal pattern. In some bird species, females proved to be more infected, in other - males. Significant differences in infection of birds of different sexes were found only for the great tit (females found to have a higher infection rate). At the same time, the analysis of total helminth infestation of all bird individuals showed that females of passerine birds carry a significant higher parasite loads. Ecological features of male and female birds affect helminth distribution in birds. Food composition is an essential factor that affects differences in invasion of both sexes of birds.

In passerine birds, song is widely used broadcasting signal. One song trait that so far has received little attention is amplitude, i.e. the sound pressure level of a song. It has been shown that there is a considerable variation in song amplitude between species, but the causes and consequences of this variation are poorly studied. Here, we measured song amplitude in two similar-sized sympatric Phylloscopus, Radde's Warbler P. schwarzi and Dusky Warbler P. fuscatus. We found that Radde's Warbler males sing much more loudly than males of Dusky Warbler. The sound pressure level values of songs of Radde's and Dusky Warblers were 78.6 ± 2.4 dB(A) (n = 16 males) and 70.9 ± 1.5 dB(A) (n = 16) at a distance of 1 m, respectively. The analysis of video-recordings revealed the larger extension of the neck region ('throat sac') in Radde's Warbler than in Dusky Warbler. We hypothesised that the larger maximum 'throat sac' volume might be responsible for the louder song of Radde's Warbler. We also found that Dusky Warbler males settled twice as close to each other than Radde's Warblers. We hypothesised that the louder song of Radde's Warbler could be useful for males of this species given their need to communicate through a larger distance. [ABSTRACT FROM AUTHOR]

Herpesviruses (HVs) were detected by PCR in the cloacal swabs of 0.76% (4/525) clinically healthy free-living passerine birds from 32 different species captured in mist nets in Slovenia during the 2014 and 2017 autumn migrations. Herpesviruses were detected in the Eurasian Blackcap (Sylvia atricapilla), the Common Blackbird (Turdus merula), and the Eurasian Blue Tit (Cyanistes caeruleus). Phylogenetic analysis of partial DNA polymerase gene nucleotide sequences of the HV strains showed a distant relationship with other alphaherpesviruses of birds. In the phylogenetic tree, the HVs detected were clustered together with HV detected in Sulphur-crested Cockatoo and Neotropic Cormorants, as well as with known HVs such as gallid HV1, psittacid HV1 and HV2, and passerine HV1. Different sequences of HVs with relatively low identity were detected in our study, suggesting that different HVs were circulating in passerines sampled during the autumn migration in Slovenia. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine reference interval intraocular pressure (IOP) values in 8 different species of companion birds. One hundred and nineteen companion birds (238 eyes) from a captive colony were examined: 21 pigeons (Columba livia; 18%), 17 African grey parrots (Psittacus erithacus; 14%), 22 common mynahs (Acridotheres tristis; 18%), 24 cockatiels (Nymphicus hollandicus; 20%), 12 zebra finches (Taeniopygia guttata; 10%), 9 budgerigars (Melopsittacus undulatus; 8%), 6 domestic canaries (Serinus canaria domestica; 5%), and 8 ring-necked parakeets (Psittacula krameri; 7%). Intraocular pressure was measured by rebound tonometry (TonoVet) avoiding induced, undesired pressure on the head, neck, or eyes. Mean IOP values varied by species. Mean (± SD) IOP values determined for each species were pigeon (5.42 ± 2.06 mm Hg), African grey parrot (4.93 ± 1.91 mm Hg), common mynah (6.22 ± 2.04 mm Hg), cockatiel (5.08 ± 1.76 mm Hg), zebra finch (5.90 ± 2.11 mm Hg), budgerigar (5.88 ± 2.31mm Hg), canary (5.83 ± 1.60 mm Hg), and ring-necked parakeet (6.25 ± 1.75 mm Hg). No statistically significant differences were found in IOP values between right and left eyes for the species studied (P >.22), with the exception of the ring-necked parakeet (P =.001). The results of this study provide representative IOP values measured using rebound tonometry in 8 different species of companion birds. [ABSTRACT FROM AUTHOR]

There is growing concern over the health of North American birds, with evidence suggesting substantial population declines. Spiders are prominent dietary items for many bird species and mediate the transfer of contaminants to arachnivorous birds that consume them. Few studies have investigated the potential risk the spider exposure pathway poses to these birds because most studies have focused on piscivores. In the present study, we developed new chronic and acute As, Cd, Cu, Pb, Ni, Se, Zn, and MeHg spider‐based avian wildlife values (SBAWVs) for multiple adult and nestling birds (primarily passerines) and then used the newly generated SBAWVs to characterize the risk to birds across 2 study areas: 1) 5 reaches in the southern Appalachian Mountains, an area with substantial mercury deposition but minimal anthropogenic impact, and 2) 4 reaches adjacent to the Emory River, an area impacted by the largest fly coal‐ash spill in US history. We identified MeHg and Cu, Pb, Se, and Zn as contaminants of potential concern (COPC) at the Appalachian Mountain and Emory River study areas, respectively, based on dietary exposure of aquatic contaminants via riparian spiders. The identification of COPC at both study areas due to dietary spider exposure is notable not only because the spider exposure pathway has largely been uninvestigated at these sites but also because the aquatic systems in both areas have been studied extensively. Significant differences in MeHg concentrations were detected among spider taxa and suggest that the selection of spider taxa can impact risk characterization. These results indicate that the spider exposure pathway is important to consider when assessing potential risk, particularly for passerine birds. Environ Toxicol Chem 2020;39:2314–2324. © 2020 SETAC [ABSTRACT FROM AUTHOR]

Behavioral interference between species can influence a wide range of ecological and evolutionary processes. Here, we test foundational hypotheses regarding the origins and maintenance of interspecific territoriality, and evaluate the role of interspecific territoriality and hybridization in shaping species distributions and transitions from parapatry to sympatry in sister species of North American perching birds (Passeriformes). We find that interspecific territoriality is pervasive among sympatric sister species pairs, and that interspecifically territorial species pairs have diverged more recently than sympatric noninterspecifically territorial pairs. None of the foundational hypotheses alone explains the observed patterns of interspecific territoriality, but our results support the idea that some cases of interspecific territoriality arise from misdirected intraspecific aggression while others are evolved responses to resource competition. The combination of interspecific territoriality and hybridization appears to be an unstable state associated with parapatry, whereas species that are interspecifically territorial and do not hybridize are able to achieve extensive fine‐ and coarse‐scale breeding range overlap. In sum, these results suggest that interspecific territoriality has multiple origins and impacts coexistence at multiple spatial scales. [ABSTRACT FROM AUTHOR]

The timing of migratory passage for sexes and ages of birds is difficult to document because migration is spread out over time and space. We compared sex and age ratios from 10 species of birds that were banded in Wisconsin during fall migration to a sample of autumn window-killed birds from Chicago, Illinois. We assumed that these specimens were a random sample of the migrating population because dates of passage in Wisconsin either predate or were coincident with specimens recovered in Chicago. More juveniles than adults collided with windows, which is expected because of the higher number of juveniles in the fall migratory population. For Connecticut Warbler (Oporornis agilis), Dark-eyed Junco (Junco hyemalis), Ovenbird (Seiurus aurocapilla), and White-throated Sparrow (Zonotrichia albicollis), statistically fewer adults collided with windows than expected. It is possible that adults of these species, who have made at least 2 prior successful migratory journeys, might have experienced some degree of learning to avoid windows. For specimen data, ratios of males to females were approximately equal, except for Swamp Sparrow (Melospiza georgiana; 1:0.82). However, banders were unable to determine sex for a high percentage of each species, ranging from 98.5% undetermined sex for Hermit Thrush (Catharus guttatus) to 48% for Common Yellowthroat (Geothlypis trichas). Taken at face value, banding records for Common Yellowthroat, Dark-eyed Junco, and White-throated Sparrow indicated a much higher percentage of males, whereas for Song Sparrow (Melospiza melodia), females were much more common; 6 species showed no apparent difference in sex ratio between the banding and window samples. In species for which banders declined to identify an individual's sex for a high percentage of birds, we questioned whether the identification of sex in the remaining small percentage was accurate. Thus, we considered the alternative possibility that the specimen data were in fact the most appropriate null hypothesis, and if so, it would suggest that banders have misidentified sexes consistently in 4 species, and ages in 7 species. [ABSTRACT FROM AUTHOR]

Strong relationships between morphological and ecological characters are commonly predicted to reflect the association between form and function, with this hypothesis being well supported in restricted taxonomic and geographical contexts. Conversely, among broader sets of species, ecological variables have been shown to have limited power to explain morphological variation.To understand these apparent discrepancies, for a large and globally distributed passerine radiation, we test whether (a) the character states of four ecological variables (foraging mode, diet, strata and habitat) have different morphological optima, (b) ecological variables explain substantial variance in morphology and (c) ecological character states can be accurately predicted from morphology.We collected 10 linear morphological measurements for 782 species of corvoid passerines, and assessed (a) the fit of models of continuous trait evolution with different morphological optima for each ecological character state, (b) variation in morphological traits among ecological character states using phylogenetically corrected regressions and (c) the accuracy of morphological traits in predicting species‐level membership of ecological character states using linear discriminant analysis (LDA).Models of morphological evolution with different ecological optima were well supported across numerous morphological axes, corresponding with significant differences in trait distributions among ecological character states. LDA also showed that membership of the ecological categories can be predicted with relatively high accuracy by morphology. In contrast to these findings, ecological variables explain limited amounts of variation in morphological traits.For a global radiation of passerine birds, we confirm that the generation of morphological variation is generally consistent with ecological selection pressures, but that ecological characters are of limited utility in explaining morphological differences among species. Although selection towards different optima means that membership of ecological character states tend to be well predicted by morphology, the overall morphospace of individual ecological character states tend to be broad, implying that morphology can evolve in multiple ways in response to similar selection pressures. Extensive variation in morphological adaptations among similar ecological strategies is likely to be a widespread phenomenon across the tree of life. [ABSTRACT FROM AUTHOR]

Parental care in birds varies among species and geographic regions. Incubation behavior influences embryonic development rate and varies substantially among species.We studied attendance at the nest by videoing nests or collecting data from the literature for 112 species in north temperate and lowland tropical sites, then associated patterns of incubation on‐ and off‐bouts with species and environmental traits.Songbirds nesting at low elevations incubate their eggs for an average of 74.1% (±12.9 SD, n = 60 species) of the time in temperate regions and 71.0% (±12.2 SD, n = 52 species) in tropical regions during daylight hours, and 84.3% (±8.2 SD) and 85.3% (±6.2 SD), respectively, of each 24‐hr cycle.While these attendance percentages do not differ significantly between latitudes, our data also show that lowland tropical songbirds make fewer visits to the nest and, consequently, have longer on‐bouts and off‐bouts during incubation. This pattern in attendance reflects a latitudinal contrast in parental care strategy, where lowland tropical birds reduce visits to the nest by increasing on‐ and off‐bout lengths while maintaining the same proportion of time spent incubating their eggs (constancy).Similar constancy across latitude suggests that tropical and temperate birds may be similarly constrained to maintain elevated egg temperatures for normal embryo growth.The different attendance strategies adopted in each region may reflect differences in ambient temperature, adult foraging time, and nest predation rate. Consistently warm ambient temperatures likely allow tropical birds to take longer off‐bouts, and thereby to reduce activity around the nest, compared to temperate birds. [ABSTRACT FROM AUTHOR]

Aim: The taxon cycle concept provides a geographically explicit and testable set of hypotheses for exploring the evolutionary processes underlying the distribution of species in space and time. Here, we test taxon cycle predictions within a large avian island radiation, the core Campephagidae and explicitly integrate the concepts of 'supertramps', 'great speciators' and relictualization. Location: The Indo‐Pacific, Australia, Asia and Africa. Taxon: Corvoid passerine birds. Methods: We constructed a new time‐calibrated molecular phylogeny of the core Campephagidae (cuckooshrikes, cicadabirds and trillers) using Bayesian phylogenetic methods. Ancestral range estimation methods and diversification rate analyses were used to explore the dispersal and diversification history of the group. We used an extensive dataset on wing morphology and range distributions to test for correlations between evolutionary age of species and dispersal capacity, diversification and distribution, while accounting for phylogenetic non‐independence. Results: The core Campephagidae represents an ecologically homogeneous radiation distributed across the Indo‐Pacific, Australia, Southeast Asia and Africa. Its members represent a continuum of dispersal abilities; some species are widespread and undifferentiated ('supertramps') or show strong differentiation of local populations ('great speciators'), and a few are endemic to single islands (relicts). We show that older species relative to younger species inhabit fewer and larger islands at higher elevations. The level of intraspecific variation measured as the number of subspecies also decreases with species age, and is highest in 'great speciators' with intermediate levels of dispersal abilities (as per hand‐wing index). Main conclusions: Based on trait correlations with species age, we infer phases of range expansion and contraction over millions of years (taxon cycles), within a single monophyletic group of birds. These observations demonstrate reconciliation of the concepts of 'supertramps', 'great speciators' and relictual palaeoendemics within the temporal stages of the taxon cycle. [ABSTRACT FROM AUTHOR]

The clutch size of passerine birds of 39 species in 3797 nests is considered. The dependence of the number of eggs in nests of northern passerine birds on the pattern of their distribution within the tundra zone and on the size of ranges, as well as the relationship of the trend of variation in the clutch size of species with different patterns of adaptation to the Subarctic, are discussed. Differences in clutch size between species nesting in different geographic zones and at different latitudes from the Ob forest tundra to northern Yamal are analyzed. The dynamics of clutch size during the nesting season and size of the first clutches, repeat clutches (that replaced the destroyed ones), and normal second clutches is described. The rule known for birds of temperate latitudes was verified for tundra passerine birds: "the earlier the onset of breeding, the larger the clutch size". [ABSTRACT FROM AUTHOR]

The importance of ecologically mediated divergent selection in accelerating trait evolution has been poorly studied in the most species‐rich biome of the planet, the continental Neotropics. We performed macroevolutionary analyses of trait divergence and diversification rates across closely related pairs of Andean and Amazonian passerine birds, to assess whether the difference in elevational range separating species pairs – a proxy for the degree of ecological divergence – influences the speed of trait evolution and diversification rates. We found that elevational differentiation is associated with faster divergence of song frequency, a trait important for pre‐mating isolation, and several morphological traits, which may contribute to extrinsic post‐mating isolation. However, elevational differentiation did not increase recent speciation rates, possibly due to early bursts of diversification during the uplift of the eastern Andes followed by a slow‐down in speciation rate. Our results suggest that ecological differentiation may speed up trait evolution, but not diversification of Neotropical birds. [ABSTRACT FROM AUTHOR]

Usutu virus (USUV, Flaviviridae) is an emerging arbovirus that has led to epizootic outbreaks in birds and numerous human neuroinvasive disease cases in Europe. It is maintained in an enzootic cycle with Culex mosquitoes and passerine birds, a transmission cycle that is shared by West Nile virus (WNV) and St. Louis encephalitis virus (SLEV), two flaviviruses that are endemic in the United States. USUV and WNV co-circulate in Africa and Europe, and SLEV and WNV co-circulate in North America. These three viruses are prime examples of One Health issues, in which the interactions between humans, animals, and the environments they reside in can have important health impacts. The three facets of One Health are interwoven throughout this article as we discuss the mechanisms of flavivirus transmission and emergence. We explore the possibility of USUV emergence in the United States by analyzing the shared characteristics among USUV, WNV, and SLEV, including the role that flavivirus co-infections and sequential exposures may play in viral emergence. Finally, we provide insights on the importance of integrated surveillance programs as One Health tools that can be used to mitigate USUV emergence and spread., (Copyright © 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Low pathogenicity avian influenza A(H7N9) virus has been detected in poultry since 2013, and the virus has caused >450 infections in humans. The mode of subtype H7N9 virus transmission between avian species remains largely unknown, but various wild birds have been implicated as a source of transmission. H7N9 virus was recently detected in a wild sparrow in Shanghai, China, and passerine birds, such as finches, which share space and resources with wild migratory birds, poultry, and humans, can be productively infected with the virus. We demonstrate that interspecies transmission of H7N9 virus occurs readily between society finches and bobwhite quail but only sporadically between finches and chickens. Inoculated finches are better able to infect naive poultry than the reverse. Transmission occurs through shared water but not through the airborne route. It is therefore conceivable that passerine birds may serve as vectors for dissemination of H7N9 virus to domestic poultry.

Species co-occurrence in local assemblages is shaped by distinct processes at different spatial and temporal scales. Here we focus on historical explanations and examine the phylogenetic structure of local assemblages of the Furnariides clade (Aves: Passeriformes), assessing the influence of diversification rates on the assembly and species co-occurrence within those assemblages. Using 120 local assemblages across Bolivia and Argentina and a nearly complete phylogeny for the clade, we analyzed assemblage phylogenetic structure, applying a recently developed model (DAMOCLES, or dynamic assembly model of colonization, local extinction, and speciation) accounting for the historical processes of speciation, colonization, and local extinction. We also evaluated how diversification rates determine species co-occurrence. We found that the assembly of Furnariides assemblages can be explained largely by speciation, colonization, and local extinction without invoking current local species interactions. Phylogenetic structure of open habitat assemblages mainly showed clustering, characterized by faster rates of colonization and local extinction than in forest habitats, whereas forest habitat assemblages were congruent with the model's equal rates expectation, thus highlighting the influence of habitat preferences on assembly and co-occurrence patterns. Our results suggest that historical processes are sufficient to explain local assemblage phylogenetic structure, while there is little evidence for species ecological interactions in avian assemblage diversity and composition. [ABSTRACT FROM AUTHOR]

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The tamarisk leaf beetle (Diorhabda carinulata), introduced from Eurasia in 2001 as a biological control agent for the invasive plant Tamarix ramosissima, has spread widely throughout the western USA. With D. carinulata now very abundant, scientists and restoration managers have questioned what influence this introduced arthropod might have upon the avian component of riparian ecosystems. From 2009 through 2012 we studied the consequences of biological invasions of the introduced tamarisk shrub and tamarisk leaf beetles on the diets of native birds along the Dolores River in southwestern Colorado, USA. We examined avian foraging behavior, sampled the arthropod community, documented bird diets and the use of invasive tamarisk shrubs and tamarisk leaf beetles by birds. We documented D. carinulata abundance, on what plants the beetles occurred, and to what degree they were consumed by birds as compared to other arthropods. We hypothesized that if D.carinulata is an important new avian food source, birds should consume beetles at least in proportion to their abundance. We also hypothesized that birds should forage more in tamarisk in the late summer when tamarisk leaf beetle larvae are more abundant than in early summer, and that birds should select beetle-damaged tamarisk shrubs. We found that D. carinulata composed 24.0 percent (± 19.9-27.4%) and 35.4% biomass of all collected arthropods. From the gut contents of 188 birds (25 passerine species), only four species (n = 11 birds) contained tamarisk leaf beetle parts. Although D. carinulata comprised one-quarter of total insect abundance, frequency of occurrence in bird gut contents was only 2.1% by abundance and 3.4% biomass. Birds used tamarisk shrubs for foraging in proportion to their availability, but foraging frequency did not increase during the late summer when more tamarisk leaf beetles were present and birds avoided beetle-damaged tamarisk shrubs. Despite D. carinulata being the most abundant arthropod in the environment, these invasive beetles were not frequently consumed by birds and seem not to provide a significant contribution to avian diets. [ABSTRACT FROM AUTHOR]

Detailed knowledge of species limits is an essential component of the study of biodiversity. Although accurate species delimitation usually requires detailed knowledge of both genetic and phenotypic variation, such variation may be limited or unavailable for some groups. In this study, we reconstruct a molecular phylogeny for all currently recognized species and subspecies of Australasian shrikethrushes ( Colluricincla ), including the first sequences of the poorly known C. tenebrosa . Using a novel method for species delimitation, the multi-rate Poisson Tree Process (mPTP), in concordance with the phylogenetic data, we estimate species limits in this genetically diverse, but phenotypically subtly differentiated complex of birds. In line with previous studies, we find that one species, the little shrikethrush ( C. megarhyncha ) is characterized by deep divergences among populations. Delimitation results suggest that these clades represent distinct species and we consequently propose a new classification. Furthermore, our findings suggest that C. megarhyncha melanorhyncha of Biak Island does not belong in this genus, but is nested within the whistlers ( Pachycephala ) as sister to P. phaionota . This study represents a useful example of species delimitation when phenotypic variation is limited or poorly defined. [ABSTRACT FROM AUTHOR]

Studies on wildlife food resources are important, providing insights into why certain species are abundant while others are not. This is based on the premise that wildlife are attracted to a particular habitat due to abundance of food resources. Small passerine birds inhabit different habitat types in Borneo, but the contribution of diet to this success is seldom investigated. This study aims to determine the diet of the passerine birds in six different habitat types, agro-, secondary, logged, primary, limestone forest and oil palm plantation. 253 individuals from 34 species of passerine birds were captured. Sources for dietary analyses comprised 149 regurgitated, 85 faecal and 33 stomach content samples, which were subsequently examined for prey items. Fifteen orders of prey items were identified, of which 14, 11, 8, 7, 6 and 3 were associated with agro-, secondary, logged, primary, limestone forest and oil palm plantation, respectively. Coleoptera were found eaten by 40% of the birds, followed by Hymenoptera (25%), Arachnidae (9.7%) and Orthoptera (7.5%). Regurgitated samples yielded 15 individuals of intact prey items whereby stomach content and faecal sample had one each. This study showed that Coleoptera are important food for small passerine birds inhabiting different habitats in Sarawak, Borneo. [ABSTRACT FROM AUTHOR]