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Climate change is altering the timing of seasonal events for many taxa. There is limited understanding of how northward/southward songbird migration follows or is limited by the latitudinal progression of seasonal transitions. Consistent environmental conditions that migrating birds encounter across latitudes likely represent or correlate with important resources or limiting factors for migration. We tested whether migratory passage-observed via radar-consistently tracked land surface variables and phenophases across latitudes in the US Central Flyway in both spring and fall. The daily temperatures, precipitation and vegetation greenness occurring on 10%, 50% and 90% cumulative passage dates changed substantially with latitude, indicating that most migrants experienced rapidly changing conditions as they headed north or south. Temperature did not limit the progression of migration in either season. Peak spring migration in the southern US occurred nearly 40 days after the spring green wave, the northward progression of vegetation growth, but nearly caught up to green-up at 48° N. Spring migration phenology may have evolved to prioritize earlier arrival for breeding. Across all latitudes, peak fall migration coincided with the same land surface phenophase, an interval of 26 days prior to dormancy onset. Migrants may rely on phenological events in vegetation during fall stopovers. Considering that (a) migratory passage tracked fall land surface phenology across latitudes at a continental scale, (b) previous studies at local scales have demonstrated the importance of fruit during fall migratory stopover and (c) fruiting phenology in North America is occurring later over time while fall migration is advancing, the potential for mismatch between fall fruiting and bird migration phenology urgently needs further investigation., (© 2024 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)

Dispersal events offer a unique window into macroevolutionary processes, especially with respect to the effects of competition on diversification. Empirical studies testing alternative predictions of competitive effects are often limited in either geographic or phylogenetic scale. Here, we tested some of these hypotheses by comparing an assemblage of 16 oscine passerine clades, representing independent dispersal events into the Western Hemisphere, to their sister clades in the Eastern Hemisphere. We also compared the diversity of this assemblage of clades to an older, incumbent passerine clade in the Western Hemisphere, the suboscines. Specifically, we tested for ecological opportunity and incumbency-mediated constraints by analysis of clade-specific morphological disparities and rates of evolution relative to dispersal history. While there was no consistent outcome of oscine dispersal and macroevolution in the Western Hemisphere relative to their Eastern Hemisphere sister groups, most clades supported a role for ecological opportunity or incumbency effects, and such effects were better explained by differences in species accumulation than by differences in rates of trait evolution or colonization timing. This general pattern was not evident when comparing the entire oscine assemblage of the Western Hemisphere to the incumbent suboscine radiation; oscines and suboscines occupy comparable regions of functional trait diversity and, despite higher rates of trait evolution in oscines, these observations were consistent with simulated null expectations. This result suggests that oscine and suboscine assemblages may have evolved in relative isolation for a significant fraction of their history., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Evolutionary Biology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Addressing the patterns of variation in thermal traits is crucial to better predict the potential effects of climate change on organisms. Here, we assessed seasonal (winter vs summer) adjustments in key thermoregulatory traits in eight Mediterranean-resident songbirds. Overall, songbirds increased whole-animal (by 8%) and mass-adjusted (by 9%) basal metabolic rate and decreased (by 56%) thermal conductance below the thermoneutral zone during winter. The magnitude of these changes was within the lower values found in songbirds from northern temperate areas. Moreover, songbirds increased (by 11%) evaporative water loss within the thermoneutral zone during summer, while its rate of increase above the inflection point of evaporative water loss (i.e., the slope of evaporative water loss versus temperature) decreased by 35% during summer - a value well above that reported for other temperate and tropical songbirds. Finally, body mass increased by 5% during winter, a pattern similar to that found in many northern temperate species. Our findings support the idea that physiological adjustments might enhance the resilience of Mediterranean songbirds to environmental changes, with short-term benefits by saving energy and water under thermally stressful conditions. Nevertheless, not all species showed the same patterns, suggesting different strategies in their thermoregulatory adaptations to seasonal environments., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to declare., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Neonicotinoids (neonics) are the most widely used insecticides worldwide and are considered to be of low risk to non-target organisms such as vertebrates. Further, they are reported to be rapidly excreted and metabolized, reducing their potential toxicity. Nevertheless, growing evidence of adverse effects of neonics on farmland bird species raise questions about the purported harmless nature of these pesticides. We attempted to search for pesticide residues in species of different trophic levels and at different life stages, by using multiple bird monitoring programs on a Long-Term Socio-Ecological Research (LTSER) platform. Three passerine birds-the blackbird (Turdus merula), cirl bunting (Emberiza cirlus), and common nightingale (Luscinia megarhynchos)-that feed on seeds and invertebrates were monitored during their reproductive period, and the grey partridge (Perdix perdix) that feeds on seeds was monitored during its wintering period. We also monitored chicks of an apex predator-the Montagu's harrier (Circus pygargus)-that preys mostly upon common voles but also upon insects. We found that the birds' blood samples showed presence of residues of five neonics: three banned since 2018 in France-clothianidin, thiacloprid, and thiamethoxam-and two-dinotefuran and nitenpyram-used for veterinary purposes only. While none of these neonics was detected in blackbirds, all were present in grey partridges. Clothianidin was detected in all species, except blackbirds. Concentrations of the three banned neonics were similar or higher than concentrations found in birds monitored elsewhere before the ban. These findings raise questions about the persistence of neonics within the environment and the mode of exposure to wild fauna. Future investigations on the sublethal effects of these neonics on life-history traits of these farmland birds may help in providing a better understanding of the effects of exposure of bird populations to these insecticides, and also to the consequent effect on human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Songbirds are one of the groups most vulnerable to extreme heat events. Although several recent studies have assessed their physiological responses to heat, most of them have focused solely on arid-zone species. We investigated thermoregulatory responses to heat in eight small-sized songbirds occurring in the Mediterranean Basin, where heatwaves are becoming more frequent and intense. Specifically, we determined their heat tolerance limits (HTLs) and evaporative cooling efficiency, and evaluated their current and future vulnerabilities to heat in southwestern Iberia, a Mediterranean climate warming hotspot. To do this, we exposed birds to an increasing profile of air temperatures (Ta) and measured resting metabolic rate (RMR), evaporative water loss (EWL), evaporative cooling efficiency (the ratio between evaporative heat loss and metabolic heat production) and body temperature (Tb). HTL ranged between 40 and 46°C across species, and all species showed rapid increases in RMR, EWL and Tb in response to increasing Ta. However, only the crested lark (Galerida cristata) achieved an evaporative cooling efficiency greater than 1. The studied songbirds currently experience summer Ta maxima that surpass the upper critical temperatures of their thermoneutral zone and even their HTL. Our estimates indicate that five of the eight species will experience moderate risk of lethal dehydration by the end of the century. We argue that the limited heat tolerance and evaporative cooling efficiency of small-sized Mediterranean songbirds make them particularly vulnerable to heatwaves, which will be exacerbated under future climate change scenarios., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)

Several cryptic avian species have been validated by recent integrative taxonomic efforts in the Sino-Himalayan mountains, indicating that avian diversity in this global biodiversity hotspot may be underestimated. In the present study, we investigated species limits in the genus Tarsiger, the bush robins, a group of montane forest specialists with high species richness in the Sino-Himalayan region. Based on comprehensive sampling of all 11 subspecies of the six currently recognized species, we applied an integrative taxonomic approach by combining multilocus, acoustic, plumage and morphometric analyses. Our results reveal that the isolated north-central Chinese populations of Tarsiger cyanurus, described as the subspecies albocoeruleus but usually considered invalid, is distinctive in genetics and vocalisation, but only marginally differentiated in morphology. We also found the Taiwan endemic T. indicus formosanus to be distinctive in genetics, song and morphology from T. i. indicus and T. i. yunnanensis of the Sino-Himalayan mountains. Moreover, Bayesian species delimitation using BPP suggests that both albocoeruleus and formosanus merit full species status. We propose their treatment as 'Qilian Bluetail' T. albocoeruleus and 'Taiwan Bush Robin' T. formosanus, respectively., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Despite the widely used application of standardized capture-handling protocols to collect blood and assess the physiological stress response, the actual sampling design (e.g., timing and the number of blood samples) often differs between studies, and the potential implications for the measured physiological endpoints remain understudied. We, therefore experimentally tested the effects of repeated handling and multiple blood sampling on the stress response in wintering free-living great tits (Parus major). We modified a well-established sampling protocol of avian studies by adding either an additional blood sample or a "sham-manipulation" (i.e., handling associated with the blood sampling procedure without venepuncture), to disentangle the effects of handling stress and blood loss. We combined three different stress metrics along the endocrine-immune interface to investigate the acute short-term stress response: total corticosterone concentrations (Cort), the heterophil/lymphocyte ratio (H:L), and the Leucocyte Coping Capacity (LCC). Our study provided three key results: i) no relationship between Cort levels, LCC and H:L, confirming that these three parameters represent different physiological endpoints within the stress response; ii) contrasting dynamics in response to stress by the measured parameters and iii) no difference in physiological stress levels 30 min after capture due to one additional blood sampling or handling event. By optimising the sampling design, our results provide implications for animal welfare and planning experimental procedures on stress physiology in passerine species., (Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: It has been proposed that divergence in the gut microbiota composition between incipient species could contribute to their reproductive isolation. Nevertheless, empirical evidence for the role of gut microbiota in speciation is scarce. Moreover, it is still largely unknown to what extent closely related species in the early stages of speciation differ in their gut microbiota composition, especially in non-mammalian taxa, and which factors drive the divergence. Here we analysed the gut microbiota in two closely related passerine species, the common nightingale (Luscinia megarhynchos) and the thrush nightingale (Luscinia luscinia). The ranges of these two species overlap in a secondary contact zone, where both species occasionally hybridize and where interspecific competition has resulted in habitat use differentiation., Results: We analysed the gut microbiota from the proximal, middle and distal part of the small intestine in both sympatric and allopatric populations of the two nightingale species using sequencing of bacterial 16S rRNA. We found small but significant differences in the microbiota composition among the three gut sections. However, the gut microbiota composition in the two nightingale species did not differ significantly between either sympatric or allopatric populations. Most of the observed variation in the gut microbiota composition was explained by inter-individual differences., Conclusions: To our knowledge, this is the first attempt to assess the potential role of the gut microbiota in bird speciation. Our results suggest that neither habitat use, nor geographical distance, nor species identity have strong influence on the nightingale gut microbiota composition. This suggests that changes in the gut microbiota composition are unlikely to contribute to reproductive isolation in these passerine birds.

Life-history traits are often plastic in response to environmental factors such as temperature or precipitation, and they also vary with age in many species. Trait variation during the lifetime could thus be partly driven by age-dependent plasticity in these traits. We study whether plasticity of a phenological trait-the egg-laying date-with respect to spring temperature, varies with age, and explore whether this variation relates to changes in breeding success throughout the life cycle. We use data from a four-decade long-term monitoring of a wild population of blue tits in Corsica, to estimate age-dependent plasticity of reproductive phenology and annual reproductive success. We show that both laying date plasticity and annual reproductive success vary with age: young and old females are less plastic, and fledge fewer offspring, than middle-age females. Furthermore, in contrast to young and prime-age females, in old females fledging success does not depend on laying date. Phenological plasticity is a major mechanism for coping with rapid environmental variation. Our results suggest that understanding its role in adaptation to climate change and population persistence requires integrating the age structure of the population., (© 2020 British Ecological Society.)

Costly interactions between species that arise as a by-product of ancestral similarities in communication signals are expected to persist only under specific evolutionary circumstances. Territorial aggression between species, for instance, is widely assumed to persist only when extrinsic barriers prevent niche divergence or selection in sympatry is too weak to overcome gene flow from allopatry. However, recent theoretical and comparative studies have challenged this view. Here we present a large-scale, phylogenetic analysis of the distribution and determinants of interspecific territoriality. We find that interspecific territoriality is widespread in birds and strongly associated with hybridization and resource overlap during the breeding season. Contrary to the view that territoriality only persists between species that rarely breed in the same areas or where niche divergence is constrained by habitat structure, we find that interspecific territoriality is positively associated with breeding habitat overlap and unrelated to habitat structure. Furthermore, our results provide compelling evidence that ancestral similarities in territorial signals are maintained and reinforced by selection when interspecific territoriality is adaptive. The territorial signals linked to interspecific territoriality in birds depend on the evolutionary age of interacting species, plumage at shallow (within-family) timescales, and song at deeper (between-family) timescales. Evidently, territorial interactions between species have persisted and shaped phenotypic diversity on a macroevolutionary timescale., Competing Interests: The authors declare no competing interest.

Our prior work has shown that live poultry vaccines have been intermittently isolated from wild birds sampled during field surveillance studies for Newcastle disease virus (NDV). Thus, we experimentally investigated the susceptibility of four native agriculturally associated wild bird species to the NDV LaSota vaccine and evaluated the shedding dynamics, potential transmission from chickens, and humoral antibody responses. To test susceptibility, we inoculated wild-caught, immunologically NDV-naïve house finches ( Haemorhous mexicanus ; n = 16), brown-headed cowbirds ( Molothrus ater ; n = 9), northern cardinals ( Cardinalis cardinalis ; n = 6), and American goldfinches ( Spinus tristis ; n = 12) with 0.1 ml (10 6.7 mean embryo infectious doses [EID 50/ml ]) of NDV LaSota vaccine via the oculo-nasal route. To test transmission between chickens and wild birds, adult specific-pathogen-free white leghorn chickens were inoculated similarly and cohoused in separate isolators with two to five wild birds of the species listed above. This design resulted in three treatments: wild bird direct inoculation (five groups) and wild bird exposure to one (two groups) or two inoculated chickens (six groups), respectively. Blood and oropharyngeal and cloacal swabs were collected before and after infection with the live vaccine. All wild birds that were directly inoculated with the LaSota vaccine shed virus as demonstrated by virus isolation (VI). Cardinals were the most susceptible species based on shedding viruses from 1 to 11 days postinoculation (dpi) with titers up to 10 4.9 EID 50 /ml. Although LaSota viruses were shed by all inoculated chickens and were present in the drinking water, most noninoculated wild birds cohoused with these chickens remained uninfected for 14 days as evidenced by VI. However, one American goldfinch tested positive for vaccine transmission by VI at 7 dpi and one house finch tested positive for vaccine transmission by real-time reverse-transcription PCR at 13 dpi. Only one directly inoculated cowbird (out of three) and two cardinals (out of two) developed NDV-specific hemagglutination inhibition antibody titers of 16, 16, and 128, respectively. No clinical signs were detected in the chickens or the wild birds postinoculation.

To evolve and to be maintained, seasonal migration, despite its risks, has to yield fitness benefits compared with year-round residency. Empirical data supporting this prediction have remained elusive in the bird literature. To test fitness related benefits of migration, we studied a partial migratory population of European blackbirds ( Turdus merula ) over 7 years. Using a combination of capture-mark-recapture and radio telemetry, we compared survival probabilities between migrants and residents estimated by multi-event survival models, showing that migrant blackbirds had 16% higher probability to survive the winter compared to residents. A subsequent modelling exercise revealed that residents should have 61.25% higher breeding success than migrants, to outweigh the survival costs of residency. Our results support theoretical models that migration should confer survival benefits to evolve, and thus provide empirical evidence to understand the evolution and maintenance of migration.

We examined thermoregulatory performance in seven Sonoran Desert passerine bird species varying in body mass from 10 to 70 g - lesser goldfinch, house finch, pyrrhuloxia, cactus wren, northern cardinal, Abert's towhee and curve-billed thrasher. Using flow-through respirometry, we measured daytime resting metabolism, evaporative water loss and body temperature at air temperatures ( T air ) between 30 and 52°C. We found marked increases in resting metabolism above the upper critical temperature ( T uc ), which for six of the seven species fell within a relatively narrow range (36.2-39.7°C), but which was considerably higher in the largest species, the curve-billed thrasher (42.6°C). Resting metabolism and evaporative water loss were minimal below the T uc and increased with T air and body mass to maximum values among species of 0.38-1.62 W and 0.87-4.02 g H 2 O h -1 , respectively. Body temperature reached maximum values ranging from 43.5 to 45.3°C. Evaporative cooling capacity, the ratio of evaporative heat loss to metabolic heat production, reached maximum values ranging from 1.39 to 2.06, consistent with known values for passeriforms and much lower than values in taxa such as columbiforms and caprimulgiforms. These maximum values occurred at heat tolerance limits that did not scale with body mass among species, but were ∼50°C for all species except the pyrrhuloxia and Abert's towhee (48°C). High metabolic costs associated with respiratory evaporation appeared to drive the limited heat tolerance in these desert passeriforms, compared with larger desert columbiforms and galliforms that use metabolically more efficient mechanisms of evaporative heat loss., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2017. Published by The Company of Biologists Ltd.)

This study evaluated the effects of environmental pollution on decreasing great tit (Parus major) breeding parameters in an industrial area in the west coast of Portugal. Several great tit breeding parameters were monitored in the industrial area, as well as in a rural area not affected by industrial emissions. Low levels of air pollution in both industrial and rural areas were confirmed by assessing trace element concentrations in pine needles. Concentrations of Cd and Hg in pine needles from the industrial area (Cd = 0.05 ppm; Hg = 0.005 ppm) were significantly lower than those found in needles collected from the reference area (Cd = 0.07 ppm; Hg = 0.007 ppm). Additionally, the breeding success of great tits increased in the industrial area in comparison to the reference area (0.93 ± 0.08 and 0.62 ± 0.22, respectively). The changes on great tit breeding parameters were probably related with changes in the breeding density of other competitive species, together with a decreasing frass-fall biomass. Further long-term ecological studies in industrial areas are necessary to understand the changing breeding performance and strategies used by great tits in response to pollution shifts in the environment.

Time constraints influence various ecological, life-history, and demographic properties of individuals and populations of many species throughout the annual cycle. Feather molt is a timely undertaking that is considered among the three most energy-demanding processes in the life cycle of birds. To deal with time pressure, passerines may shorten their molt duration, using three non-mutually exclusive mechanisms: (1) replacing only part of the plumage, (2) increasing the speed of molt, and (3) postponing the renewal of some or all the plumage to a later season (i.e., from the summer to the overwintering period). We used a comparative approach by measuring 12,349 individuals from 134 passerine species to explore how feather molt of juvenile and adult passerines is evolutionarily modulated under time constraints. The results indicate that breeding at northern latitudes and long-distance migration limit the time available for molt and that the consequences of time constraints were age dependent. While the duration of adult summer molt decreased, the extent, rather than the duration, of juvenile molt declined under time constraints. This study highlights the importance of considering time constraints in order to enhance the understanding of selective forces that shape life-history processes and their consequences throughout the annual routine.

Animals that use flight as their mode of transportation must cope with the fact that their migration and orientation performance is strongly affected by the flow of the medium they are moving in, that is by the winds. Different strategies can be used to mitigate the negative effects and benefit from the positive effects of a moving flow. The strategies an animal can use will be constrained by the relationship between the speed of the flow and the speed of the animal's own propulsion in relation to the surrounding air. Here we analyse entomological and ornithological radar data from north-western Europe to investigate how two different nocturnal migrant taxa, the noctuid moth Autographa gamma and songbirds, deal with wind by analysing variation in resulting flight directions in relation to the wind-dependent angle between the animal's heading and track direction. Our results, from fixed locations along the migratory journey, reveal different global strategies used by moths and songbirds during their migratory journeys. As expected, nocturnally migrating moths experienced a greater degree of wind drift than nocturnally migrating songbirds, but both groups were more affected by wind in autumn than in spring. The songbirds' strategies involve elements of both drift and compensation, providing some benefits from wind in combination with destination and time control. In contrast, moths expose themselves to a significantly higher degree of drift in order to obtain strong wind assistance, surpassing the songbirds in mean ground speed, at the cost of a comparatively lower spatiotemporal migratory precision. Moths and songbirds show contrasting but adaptive responses to migrating through a moving flow, which are fine-tuned to the respective flight capabilities of each group in relation to the wind currents they travel within., (© 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.)

Urbanization is one of the most extensive and ecologically significant changes happening to terrestrial environments, as it strongly affects the distribution of biodiversity. It is well established that native species richness is reduced in urban and suburban areas, but the species traits that predict tolerance to urbanization are yet little understood. In birds, one of the most studied groups in this respect, evidence is appearing that acoustic traits influence urban living, but it remains unknown how this compares to the effects of more obvious ecological traits that facilitate urban living. Therefore, it remains unclear whether acoustic communication is an important predictor of urban tolerance among species. Here, with a comparative study across 140 European and North American passerines, I show that high song frequency, which is less masked by the low-frequency anthropogenic noise, is associated with urban tolerance, with an effect size over half that of the most important ecological trait studied: off-ground nesting. Other nesting and foraging traits accepted to facilitate urban living did not differ for species occurring in urban environments. Thus, the contribution of acoustic traits for passerine urban tolerance approximates that of more obvious ecological traits. Nonetheless, effect sizes of the biological predictors of urban tolerance were low and the phylogenetic signal for urban tolerance was null, both of which suggest that factors other than phenotypic traits have major effects on urban tolerance. A simple possibility is exposure to urbanization, as there was a higher proportion of urban-tolerant species in Europe, which is more urbanized than North America., (© 2013 John Wiley & Sons Ltd.)

As offshore wind (OSW) energy expands globally, migratory songbirds are at risk of mortality from collisions with turbine blades, though the magnitude of this threat and which species are most vulnerable, remains poorly understood. Ecological vulnerability indices are commonly used to assess species' susceptibility to harmful factors, with results used to direct scarce research and monitoring resources to species showing relatively high vulnerability. These indices are based on the traits that elevate a species risk to adverse impacts (sensitivity), the overlap in occurrence between a species and the potentially harmful agent (exposure) and the influence of this exposure on the species' local or global persistence (resilience). We modified ecological vulnerability indices for seabirds to assess vulnerability of migratory songbirds to OSW related mortality. As a pertinent case study, we considered songbirds that fly across the Northwest Atlantic during their autumn migration. We utilized readily available information on each species' migratory behaviour, life history, and conservation status to calculate an index score that could range from 1 (lowest vulnerability) to 125 (highest vulnerability). We found scores of 3 to 55.2 for the 101 songbird species evaluated, with New World warblers (Parulidae) over‐represented among the highest scoring species. We found the scores to be sensitive to uncertainty in index components, highlighting the importance of considering scoring uncertainty when evaluating ecological vulnerability indices. Finally, we found that for seven of the top 10 highest scoring species, modest improvements in population trends had the potential to lower the scores substantially. Synthesis and applications. Our methodology is readily applicable to other regions where offshore wind (OSW) development is planned and songbird migration is common, allowing research and monitoring activities to be targeted to species most likely to be negatively affected by OSW facility encounters. [ABSTRACT FROM AUTHOR]

The pinyon jay Gymnorhinus cyanocephalus is listed as Vulnerable by the IUCN Red List of Threatened Species due to its continued decline in the wild caused by impacts to its unique pinyon-juniper woodland habitat. Recent reviews do not mention commercial trade as a threat and no information is given on use and trade at all. Here we provide evidence of recent international trade in pinyon jays observed in the European Union. We recommend listing the species in Appendix III of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to enable the monitoring of international trade. Additionally, the desirability of a listing in a higher appendix of CITES at the next Conference of the Parties, as a more restrictive measure, should be assessed, as it may provide a necessary tool to prevent illegal international trade from becoming an additional threat for this unique North American songbird. [ABSTRACT FROM AUTHOR]

As the Arctic becomes increasingly accessible to the resource extraction industry, an understanding of the impacts of infrastructure and anthropogenic disturbance on tundra-nesting avian populations is critical. We conducted breeding bird surveys using point counts and Program for Regional and International Shorebird Monitoring (PRISM) rapid surveys at the Hope Bay Project, an underground gold mine in Nunavut, Canada, from 2007 to 2015. We examined the relationship between abundance of total birds, songbirds, and shorebirds with distance from infrastructure, anthropogenic disturbance (i.e., activity at the mine site), and environmental covariates. Contrary to our predictions, anthropogenic disturbance showed no significant effect on bird abundance for either survey type or bird grouping. However, total bird abundance was associated with distance from infrastructure for both survey methods. A relationship with distance to infrastructure, with variability in influence, was also present for songbird point count data and shorebird PRISM data, but was not significant for songbirds recorded during PRISM surveys. Habitat type played a vital role in determining avian abundance, with PRISM surveys showing that wet lowland ecotypes supported higher bird numbers, whereas point count data revealed a more nuanced habitat association, likely reflecting the specific habitat preferences of different songbirds. Our study highlights the need for strategic planning of industrial development, incorporating comprehensive monitoring and ensuring the protection of preferred Arctic-breeding bird habitats. By aligning development projects with environmental objectives, we can ensure the coexistence of industrial interests and the future of avian populations in the Arctic. [ABSTRACT FROM AUTHOR]

The cause of recent population declines in some farmland/hedgerow breeding bird species in the UK is related to a lack of cover and food resources in winter. In improved grassland areas some of those declines have been particularly acute and some have been shown to be related to the availability of grass and weed seed in winter. The provision of seed‐bearing crops as part of AES options has been shown to benefit some of these birds. Game crop plots sown on shooting estates for holding and driving gamebirds in autumn and winter have been shown to hold relatively high densities of farmland and wood‐edge birds during the winter. We studied breeding songbirds in hedges in a primarily improved grassland area in the SW of England where there are some large shooting estates that sow relatively large game crop plots (1–5 ha) in the landscape. In this study we found that otherwise similar hedges in terms of size and density near to those winter game crop plots, had between 1.5 and 2 times as many breeding resident songbirds per unit length the following spring compared to hedges further away from game crop plots. This was despite game management in these plots being wound down during February and in many cases, the crops themselves being removed by mid‐March. Hedges within approximately 350 m from game crop plots had more breeding birds. We discuss possible mechanisms and suggest that some passerines preferentially establish breeding territories in hedges near to game crops in late winter. We suggest how to distribute game crop plots to maximise any benefit in an improved grassland landscape. [ABSTRACT FROM AUTHOR]

The hyper‐diverse clade Passeriformes (crown group passerines) comprises over half of extant bird diversity, yet disproportionately few studies have targeted passerine comparative anatomy on a broad phylogenetic scale. This general lack of research attention hinders efforts to interpret the passerine fossil record and obscures patterns of morphological evolution across one of the most diverse clades of extant vertebrates. Numerous potentially important crown passeriform fossils have proven challenging to place phylogenetically, due in part to a paucity of phylogenetically informative characters from across the passerine skeleton. Here, we present a detailed analysis of the morphology of extant passerine carpometacarpi, which are relatively abundant components of the passerine fossil record. We sampled >70% of extant family‐level passerine clades (132 extant species) as well as several fossils from the Oligocene of Europe and scored them for 54 phylogenetically informative carpometacarpus characters optimised on a recently published phylogenomic scaffold. We document a considerable amount of previously undescribed morphological variation among passerine carpometacarpi, and, despite high levels of homoplasy, our results support the presence of representatives of both crown Passeri and crown Tyranni in Europe during the Oligocene. [ABSTRACT FROM AUTHOR]

Passerine birds are widely distributed and adapted to various habitats, therefore they are commonly exposed to, and infected with Toxoplasma gondii. The purpose of our project was to determine the prevalence and genotypes of T. gondii in 31 different species of passerines collected as mortalities due to window collisions in North-Central Oklahoma. DNA was extracted from breast tissue and subjected to PCR with primers that amplify a portion of the T. gondii B1 gene. Genotyping was based on a portion of the infected birds based on a multiplex PCR followed by RFLP of 12 T. gondii markers. Of 103 birds comprising 31 species, the overall prevalence (95% confidence interval) of T. gondii infection was 33.0% (24.1‒42.6%). Significant differences in the proportion of T. gondii in birds according to sex or weight were not observed. However, sample sizes of each species were small and prevented a robust analysis of T. gondii according to those biological variables. Genotyping of T. gondii in a subset of 13 infected individuals of 7 species revealed 4 genotypes, according to the Toxoplasma Data Base: #54, #139, #20, and #220. Our results, while hampered by a small sample size for each bird species, suggest that infection with T. gondii in Oklahoma, is common in both migrant and resident passerines. [ABSTRACT FROM AUTHOR]

Birds are among the most exploited animals due to their melodious songs and attractive plumage, but few studies explore the clandestine bird trade at local markets. To assess the bird trade in Mexico City, we recorded the number of individuals of each species for sale in three markets during two periods of 2012-2013 and 20152016. We recorded 74 bird species for sale, with a total of 20,388 individuals in 2012-2013 and 20,004 individuals in 2015-2016 of all species in the three markets. This included 11 species of native Psittaciformes whose sale is prohibited in Mexico, as well as eight internationally endangered or threatened species, and six species in CITES Appendix I prohibiting their trade. The overall number of birds for sale, and the number of non-native (-15,000 - 18,000) birds for sale, remained constant between the two periods. However, we found a significant increase in the number of individuals of native bird species for sale, from 1,892 birds in 2012-2013 to 4,506 native birds in 2015-2016. We recorded 24 species of songbirds that also increased significantly between periods as almost all songbirds were native species. Our results demonstrate that the sale of companion, ornamental and songbirds has persisted in Mexico City markets, with non-native species selling in consistently high numbers, and a significant increase in the number of native birds for sale. This indicates a high demand for singing and ornamental birds, with associated risks of introducing non-native species, and illegal trade of species at risk that affects threatened populations. [ABSTRACT FROM AUTHOR]

Socially guided vocal learning, the ability to use contingent reactions from social partners to guide immature vocalizations to more mature forms, is thought to be a rare ability known to be used only by humans, marmosets and two unrelated songbird species (brown-headed cowbirds and zebra finches). However, this learning strategy has never been investigated in the vast majority of species that are known to modify their vocalizations over development. We propose a novel, preliminary evolutionary modelling approach that uses ecological, reproductive and developmental traits to predict which species may incorporate social influences as part of their vocal learning system. We demonstrate our model using data from 28 passerines. We found three highly predictive traits: temporal overlap between sensory (memorization) and sensorimotor (practice) phases of song learning, song used for mate attraction, and social gregariousness outside the breeding season. Species with these traits were distributed throughout the clade, suggesting that a trait-based approach may yield new insights into the evolution of learning strategies that cannot be gleaned from phylogenetic relatedness alone. Our model suggests several previously uninvestigated and unexpected species as likely socially guided vocal learners and offers new insight into the evolution and development of vocal learning. This article is part of the theme issue 'Vocal learning in animals and humans'. [ABSTRACT FROM AUTHOR]

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Deuterium composition of feathers has been widely applied to establish provenance of birds. Surprisingly, little attention has been paid to the potential sources of unwanted hydrogen isotopic variability that may affect the comparability and replicability of deuterium measurements. Feathers may exhibit hydrogen isotopic differences between distal and proximal sections, as well as between rachis and vane. For this reason, it is recommended to always analyse ground vane from the same section of the feather. However, this protocol may be seriously limiting when working with songbird feathers, which are usually small and light. In this paper, intra-feather hydrogen isotopic variability was studied in four species of songbirds by comparing four sections of the same feather. No difference in hydrogen isotopic composition was found between distal and proximal sections of the vane. This was expected as songbird feathers grow rapidly and individuals avoid geographical movements during moult, favouring a homogeneous source of hydrogen during keratin synthesis. Conversely, as previously demonstrated for other avian species, rachis showed systematically c. 11‰ δ2H more negative values than vane. This is probably a result of their biochemical and ultrastructural differences, which seem strongly conserved across taxa. Such differences imply that we need to describe which feather part was used in the methods of our reports to ensure full comparability and replicability among studies. Nevertheless, vane and rachis δ2H were strongly correlated, demonstrating that rachis can be also used in isotope analyses because its δ2H can be accurately rescaled. This is useful since rachis represents an important fraction of feather mass in songbirds. Values of δ2H from ground and non-ground samples from the same feather were also compared. There was no effect of the processing protocol, suggesting that grinding is unnecessary when working with passerine feathers. [ABSTRACT FROM AUTHOR]

When vegetation structure is altered, songbird communities may be affected. Despite speculation that African Elephant (Loxodonta africana) browsing impacts bird communities, existing data are limited. I sampled the bird communities of the Albany Thicket Biome at 10 sites in the Eastern Cape, South Africa, half with elephants and half without. Songbird community parameters were best predicted by how long elephants had been present, elephant density and the percentage cover of thicket vegetation. The sites where elephants had been present for longer had more bird species and increased songbird density and diversity. However, bird density also increased with increasing thicket vegetation cover and this is a phenomenon unlikely to be compatible with long-term elephant presence. There was an almost equal split between the number of bird species that appeared to be negatively affected by changes in habitat structure (47%) and those which benefited (53%). Smaller birds were generally more abundant as vegetation structural integrity increased and larger birds were more abundant when vegetation structural integrity declined. The browsing of elephants could be viewed as facilitative for songbirds in the short term. However, this effect may not persist in the long term because all elephant populations (notorious tree-fellers) in the Eastern Cape are found in fenced areas where natural migration is not possible. More broadly, my data provide important insight into how avian communities respond to habitat transformation at the local and regional scales. [ABSTRACT FROM AUTHOR]

Summary: A widely applied method of experimentally determining migratory activities and directions is the so called Emlen-funnel cage, using typewriter correcting paper (Tipp-Ex©) for the registration. We investigated methodical biases, with respect to its construction, environmental condition and the determination of activity and mean direction. The experimental birds were slightly attracted by the joint of the Tipp-Ex© paper. Small songbirds left two different kinds of claw marks: clearly visible ones (cover of the typewriter correcting paper scratched off), and vague ones, which only can be detected in appropriate light conditions (cover not scratched off but pressed). Small songbirds (e.g. Reed WarblersAcrocephalus scircapeus, Willow WarblersPhylloscopus trochilus) produced almost exclusively weak scratches, and therefore would often be classified mistakenly as inactive, if only the clearly visible scratches were counted. The relative number of well visible scratches was positively correlated with increasing atmospheric humidity, since the cover of the typewriter correcting paper is more likely to be scratched off when humidity is high. Consequently, the bird's activity is underestimated in dry air conditions. In a sample of 55 experiments no difference was found in mean direction and concentration, when preferred individual directions were (1) estimated visually, (2) assumed to be the angles with most scratches, and (3) calculated by vector addition of the single scratches. Repetitive counts of the scratches in single experiments resulted in an error for the individual mean vector of ± 12° (90%-confidence intervall). [ABSTRACT FROM AUTHOR]

Many bird species produce temporally coordinated duets and choruses, requiring the rapid integration of auditory perception and motor production. While males and females of some species are known to participate in these displays for sex-specific purposes, few studies have identified perceptual features that trigger sex-specific contributions of coordinated song. Especially little is known about perception and production in duetting suboscine passerines, which are thought to have innate songs and largely static, rather than dynamic, vocal behavior. Here, we used synthetic stimuli in a playback experiment on chestnut-backed antbirds (Myrmeciza exsul) to (1) test whether differences in song frequency (Hz) can trigger sex-specific vocal behavior in a suboscine passerine (2) test for the functions of duetting in males and females of this species, and (3) determine whether these suboscines can dynamically adjust the temporal and spectral features of their songs. We found sex-specific responses to synthetic playback manipulated in song frequency (Hz), providing evidence that in this context males sing in duets for general territory defense and females join in for mate guarding purposes. In addition, we found that the birds altered the frequency, duration, and timing of their songs depending on the frequency of the playback songs. Thus, we show that these birds integrate spectral and temporal information about conspecific songs and actively modulate their responses in sex-specific ways. [ABSTRACT FROM AUTHOR]

Madagascar is renowned as a global biodiversity hotspot with high levels of microendemism. However, there are few molecular phylogenetic studies of Malagasy birds, particularly for forest-dwelling species, signifying a substantial gap in current measures of species diversity in the absence of genetic data. We evaluated species limits and explored patterns of diversification within the genus Newtonia (Family Vangidae), a group of forest-dwelling songbirds endemic to Madagascar. Our modern systematics approach combined genomic, morphometric, and ecological niche data to analyze the evolutionary history of the group. Our integrative analysis uncovered hidden species-level diversity within N. amphichroa , with two deeply divergent and morphologically distinct lineages isolated in different regions of humid forest. We describe the southern lineage as a new species. Conversely, N. brunneicauda , which we initially hypothesized may harbor cryptic diversity owing to its large distribution spanning a range of habitats, was found to have no distinct lineages and shared haplotypes across much of its distribution. The contrasting diversification patterns between Newtonia lineages may be the result of their elevational tolerances. Newtonia brunneicauda has a broad habitat tolerance and elevational range that appears to have facilitated population expansion and gene flow across the island, limiting opportunities for diversification. On the other hand, N. amphichroa is found predominantly in mid-elevation and montane humid forests, a restriction that appears to have promoted speciation associated with climatic fluctuations during the Pleistocene. Our findings indicate that species diversity of Malagasy forest-dwelling birds may be greater than currently recognized, suggesting an urgent need for further studies to quantify biodiversity in Madagascar’s rapidly disappearing native forests. [ABSTRACT FROM AUTHOR]

Aim: To inform conservation planning in the face of climate change, our objectives were to map spatial patterns of tree and songbird macrorefugia; to identify climatic limiting factors by region and taxonomic group; and to quantify multi-scale topographic components of end-of-century biotic refugia. Location: United States and Canada outside the far north. Time period: End of the 21st century. Major taxa studied: Trees and songbirds. Methods: We used species distribution models for 324 trees and 268 songbirds to develop a macrorefugia index using species-specific climate velocity. Maps of multispecies refugia potential were developed for each taxonomic/functional group and quantile regression was used to identify climatic limiting factors and relationships with multi-scale topographic variables. Results: End-of-century macrorefugia for both trees and songbirds were concentrated in western mountains and, to a lesser extent, in north-eastern coastal regions. For the highest-value refugia, precipitation was generally most limiting in the north, and warm temperatures and moisture availability were limiting in the south. Tree refugia were more limited by precipitation and moisture, while songbird refugia were more limited by temperature. Upper-percentile refugia, but not median values, were well explained by topographic conditions. Songbird refugia were strongly associated with elevation, while coastal proximity and landform composition (particularly headwaters) were important for both groups. There was a general lack of concordance between patterns of current species richness and future climate refugia. Main conclusions: Macrorefugia patterns are partly explained by steep elevational or latitudinal temperature gradients and/or moderate climates, such as coastal regions. However, climatic limiting factors for these refugia suggest contrasts in the ecological processes governing warm-end range limits for different taxa in different regions. Our framework can be applied to other regions, taxa, and time periods to generate and explain biologically meaningful indices of macrorefugia for conservation planning. [ABSTRACT FROM AUTHOR]

Migratory species employ a variety of strategies to meet energetic demands of postbreeding molt. As such, at least a few species of western Neotropical migrants are known to undergo short-distance upslope movements to locations where adults molt body and flight feathers (altitudinal molt migration). Given inherent difficulties in measuring subtle movements of birds occurring in western mountains, we believe that altitudinal molt migration may be a common yet poorly documented phenomenon. To examine prevalence of altitudinal molt migration, we used 29 years of bird capture data in a series of linear mixed-effect models for nine commonly captured species that breed in northern California and southern Oregon. Candidate models were formulated a priori to examine whether elevation and distance from the coast can be used to predict abundance of breeding and molting birds. Our results suggest that long-distance migrants such as Orange-crowned Warbler ( Oreothlypis celata) moved higher in elevation and Audubon's Warbler ( Setophaga coronata) moved farther inland to molt after breeding. Conversely, for resident and short-distance migrants, we found evidence that birds either remained on the breeding grounds until they finished molting, such as Song Sparrow ( Melospiza melodia) or made small downslope movements, such as American Robin ( Turdus migratorius). We conclude that altitudinal molt migration may be a common, variable, and complex behavior among western songbird communities and is related to other aspects of a species' natural history, such as migratory strategy. [ABSTRACT FROM AUTHOR]

Most songbirds depart from stopover sites after sunset and migrate during the night. Several recent studies have reported larger variation in departure time than previously thought; yet, it is still unclear which factors govern departure timing. We investigated the departure timing of four species of nocturnally migrating songbirds using an automated radiotelemetry system at Falsterbo peninsula in southwest Sweden. We made a comprehensive analysis to test a range of factors that have been hypothesized to affect departure timing of nocturnal migrants, such as night duration, season, sun elevation and the birds' intrinsic and environmental conditions. We hypothesized that birds in good condition (large fuel reserves) and under advantageous flight conditions would depart sooner after sunset, in the expected migratory direction. Our analyses showed that the birds departed sooner after sunset during spring than autumn, and different species departed at different times in relation to sunset. In addition, birds departed earlier when nights were shorter, suggesting that night duration is an important factor that may drive much of the observed timing differences between seasons and species. Lean birds delayed their departures compared to fat individuals. When birds experienced favourable wind conditions (tail wind or weak winds) at sunset, they departed earlier. Thus, it appears that the decision to take off for a long-distance flight depends on both body condition and wind conditions. Timing of departure was not correlated with sun elevation, which would have been expected if availability of specific orientation cues (sun, skylight polarization pattern, stars) acted as triggers for departures. These results stress high flexibility and adaptive responses to a complex of ecological factors as the determinants for timing of nocturnal flights in songbirds. [ABSTRACT FROM AUTHOR]

Songbird species (order Passeriformes, suborder Oscines) are important models in various experimental fields spanning behavioural genomics to neurobiology. Although the genomes of some songbird species were sequenced recently, the chromosomal organization of these species is mostly unknown. Here we focused on the two most studied songbird species in neuroscience, the zebra finch (Taeniopygia guttata) and the canary (Serinus canaria). In order to clarify these issues and also to integrate chromosome data with their assembled genomes, we used classical and molecular cytogenetics in both zebra finch and canary to define their chromosomal homology, localization of heterochromatic blocks and distribution of rDNA clusters. We confirmed the same diploid number (2n = 80) in both species, as previously reported. FISH experiments confirmed the occurrence of multiple paracentric and pericentric inversions previously found in other species of Passeriformes, providing a cytogenetic signature for this order, and corroborating data from in silico analyses. Additionally, compared to other Passeriformes, we detected differences in the zebra finch karyotype concerning the morphology of some chromosomes, in the distribution of 5S rDNA clusters, and an inversion in chromosome 1. [ABSTRACT FROM AUTHOR]

Human activities may generate geometrical landscape (i.e. composed of rectilinear and repetitive landscape units) structures that can significantly influence the spatial distribution of birds. While bird distribution in various landscape types has been extensively studied, the role played by landscape configuration and composition in different facets of bird diversity remains unclear. Here, these two main components of landscape characteristics (i.e. configuration and composition) are disentangled and their relative influence on three different facets of bird assemblages: taxonomic and functional characteristics, and the presence of rare species, is tested. We chose four large coastal salinas of Western France as a relevant model of geometrical and human-dominated landscapes where each landscape unit can be easily identified and mapped. The landscape characteristics of these sites were mapped and quantified. Then, terrestrial breeding birds were sampled in 172 point-counts using a standardized protocol. 69 diurnal terrestrial bird species were detected and considered in analyses (waterbirds and owls excluded). Landscape composition was found to have a higher influence on bird communities than landscape configuration, which fits with the 'landscape composition hypothesis'. More specifically, the most 'extreme' landscapes - those with low terrestrial surface areas, low landscape richness and diversity, low cohesion, and very patchy landscapes with complex geometrical shapes - host the lowest bird taxonomic abundance, richness and diversity and functional richness, but are characterized by the presence of rare species (mainly wetland specialist species, e.g. Reed Bunting Emberiza schoeniclus and species with restricted ranges e.g. Bluethroat Luscinia svecica namnetum). Our results suggest that conservation plans in such geometrical and human-dominated habitats should not only focus on one aspect of landscape characteristics or one aspect of biological diversity but also consider the adverse effects of landscape characteristics on these different facets. [ABSTRACT FROM AUTHOR]

Collision with glass windows is a leading anthropogenic cause of direct mortality for avian species and much attention has been given to developing methods to reduce the incidence of bird collisions. Little empirical research exists, however, examining the mechanisms by which birds might be deterred from human structures. We tested the efficacy of ultraviolet (UV) lights for preventing window strikes in an urban environment by measuring their deterrence effect at bird feeders at eight residential sites. We used remote cameras to count feeder visits over one winter in response to rotating treatments comprising a pulsating UV light, a light-reflecting compact disc, an unlit UV light as a novel object, and a control with no object. Using generalized linear mixed models, we showed that feeder visit rates were influenced by wind speed, site, and site-treatment interactions. The unlit novel object treatment yielded a visitation rate significantly higher than the control ( p = 0.01). The UV and passive reflecting treatments slightly increased visitation above the control ( p = 0.06 and p = 0.378, respectively). This suggests that novel objects may serve as an attractant in a foraging context and that this effect is stronger than any deterrence effect of UV light. The site-treatment interaction indicated that each of the four treatments produced the highest visitation rate for at least one of the sites. Rather than offer a biological explanation for this interaction, we speculate that it resulted from a spurious effect of temporal and spatial variation in bird activity that interacted with our randomized block design. Although we found no evidence that UV lights would deter urban songbirds from anthropogenic structures, their potential to attract attention may reduce the likelihood that birds fail to see and then collide with windows. [ABSTRACT FROM AUTHOR]

The author provides an osteological guide to songbirds, based on 11 skeletal parts of 51 genera, at the genus level for ornithologists studying owl pellets, paleontologists and archaezoologists. The mandible, the coracoid bone, the scapula, the humerus, the ulna, the carpometacarp, the first phalanx bone of the second finger, the femur, the tibiotars, the tarsometatars and the claw bone are presented. The morphological characteristics and method of measurement of the examined skeletal parts and the photographs of the appropriate bones are illustrated on 52 plates and 17 figures. The measurement data are also provided in 11 size tables. For every discussed bone, 3-6 characteristics are chosen, and their codes consist of 3-6 letters. In case of overlaps, dimensions are the determining factors, and for the humerus and the ulna, the ensemble of the two bone end pairs can be used. [ABSTRACT FROM AUTHOR]

Increased losses of green areas in cities reduce people's experience of flora and fauna. Earlier studies have shown that biodiversity has benefits for urban inhabitants but the influence of animal sounds on people's experience of green space is poorly known. A sample of young urban people (N = 227) rated their reactions - positive or negative - to three bird song combinations: House Sparrow (Passer domesticus), Willow Warbler (Phylloscopus trochilus), 7 spp. i.e. Willow Warbler, Chaffinch (Fringilla coelebs), Blue Tit (Cyanistes caeruleus), Great Tit (Parus major), European Robin (Erithacus rubecula), Common Blackbird (Turdus merula), Great Spotted Woodpecker (Dendrocopos major), three urban settings (residential areas with varying amount of greenery) and nine combinations of song and setting. Bird song was generally considered positive and singing by several species was more highly rated than singing by a single species. On average, urban settings combined with bird song were more highly appreciated than the settings alone and even more so where there was singing by several species rather than just one. We conclude that our data support the idea that bird song contributes to positive values associated with urban green space. Urban planners should consider preserving a variety of habitats in cities for hosting a diversity of birds and thereby boost conservation of songbird diversity and recreational experiences for urban people. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Field Ornithology 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.)

ABSTRACT Conservation efforts are most effective when we have complete demographic information for a species of concern. Nevertheless, fundamental gaps in our knowledge of demography still exist for many taxa. For passerine birds, the period of time directly after young birds leave the nest and before they disperse and/or migrate (i.e., the post-fledging period) remains an understudied life stage. We reviewed the literature on survival of passerine birds during the post-fledging period to synthesize current knowledge on survival rates and the factors affecting these rates, and conducted a sensitivity analysis to explore the relationship between population growth and post-fledging survival across the range of rates reported in the literature. Fledgling age was a strong predictor of survival, with the highest mortality occurring during the first 3 weeks after birds fledged. Among species, survival ranged from 0.23 to 0.87 during the first 3 weeks post-fledging and increased with adult body mass and nestling period duration. The relatively high proportion (12 of 19; 63%) of studies that detected at least 1 habitat effect on survival indicates that management focused on post-fledging habitat can improve survival. Sensitivity analyses indicated that post-fledging survival rates less than approximately 0.4 require unrealistic overwinter survival rates of juveniles to prevent population decline, unless adult survival rates and seasonal fecundity are high. Post-fledging survival is a useful metric for monitoring passerine populations because it sets the ceiling on first-year survival, responds to habitat management, and leads to more comprehensive demographic models for songbirds. © 2014 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Understanding how weather influences survival and reproduction is an important component of forecasting how climate change will influence wildlife population viability. Nest predation is the primary source of reproductive failure for passerine birds and can change in response to temperature. However, it is unclear which predator species are responsible for such patterns because predation events are rarely observed. We investigated whether temperature influenced predator-specific rates of nest predation by analyzing data from six prior studies conducted between 1997 and 2010 in Texas, Illinois, and Missouri that used constant-surveillance video systems to identify predators at the nests of Golden-cheeked Warblers (Setophaga chrysoparia), Blackcapped Vireos (Vireo atricapilla), Indigo Buntings (Passerina cyanea), and Acadian Flycatchers (Empidonax virescens). Rates of nest predation by snakes and birds increased as daily maximum temperatures increased, whereas predation by mammals was essentially invariant in response to temperature. The relative roles of physiological versus community-level mechanisms (e.g., abundance or behavior of predators and/or alternative prey) in driving the patterns we observed remain unclear, but our data point to the need to consider important biological interactions when forecasting the effects of climate change on songbird populations. [ABSTRACT FROM AUTHOR]

The article focuses on the techniques used for monitoring population trends of migratory songbirds to assess changes in population indices in Rhode Island. The method to achieve the goal included estimation of population trends based on annual variation at two banding stations in Rhode Island. The results showed that the banding stations are used to monitor population trends of many species and could be used to supplement monitoring programs at large scale.

The article presents a study which focuses on the development of methods for estimating the levels of take for passerines for Nearctic species involved in the Mexican wild-caught bird trade. The study uses the theta-logistic population model for setting the allowable levels of take for 11 species of passerines. Results show that the levels of take authorized by the government in Mexico for the 11 species in 2010 were small compared to relatively conservative allowable levels of take.

The article presents the study conducted regarding the success of breeding the migratory songbirds in the harvested boreal forests in northwestern Newfoundland and Labrador. The study aims to determine the impact of forest harvest on the success pf passerines breeding and the natural harvesting on the harvesting consequences. The result from a series of nests and banded hatch-year birds monitoring shows that spatial and temporal heterogeneity have complex interactions in the forest harvest and the daily survival of nests are significantly associated to the harvest proportion.