Search

The article focuses on a study which examined the migration strategy, specifically stopover duration and fuel load, of bluethroats Luscina svecica cyanecula in northern Iberia during the autumn migration period. Data were obtained in the reed bed Phragmites australis that surrounds the Badina de Escudera lagoon near Villafranca, Spain. Stopover duration was calculated by means of minimum stopover duration and Cormack-Jolly-Seber models. Findings reveal that the stopover duration was nearly 30 days and that adults were more fuel loaded than juveniles. The article notes that the results suggest that birds with long stopovers were not true fuelling migrants but wintering birds with balanced energy budgets.

The article discusses a study that determines whether plumage coloration is a valid criterion for defining and identifying White-throated Dipper types and its distribution in Spain. It refers to two types of White-throated Dipper existing in Spain, the Cincluse cinclus (C.c.) in the northwestern and central regions and C.c. aquaticus in the eastern and southern regions. Dippers were captured with mist-nets in ten representative zones within the Dippers' range in Spain. It suggests that plumage features alone cannot determine these birds.

The article discusses the impact of sampling frequency (SF) in determining differential timing of migration. Previous reports indicate that migration schedules were affected by age in autumn when adults migrate earlier and by sex in spring when males start earlier. The Blackcaps Sylvia atricapilla songbird was chosen due to the available numbers and the ease of determining age and sex. In the autumn of 2005 and spring of 2006, Blackcaps were marked in a 48-hectare area in Loza, Spain, that is used as breeding ground by local birds and as a stopover site by foreign birds. Results show that differential timing between sexes or age classes was detectable at certain levels of SF but not at lower SF. In spring, differential timing between age classes only became significant with daily sampling.

The article focuses on the study which examines the migration strategies of goldfinches Carduelis carduelis as they pass through the western edge of Pyrenees. The study considered the species' time-associated variations in age and sex ratios and morphology. It was carried out through systematic sampling sessions during a specific period. After data analysis, it was revealed that spring migrants showed a shorter wing and tail and were more fuel loaded than birds from autumn and winter. Adults also tended to pass later than juveniles during the autumn season.

The article focuses on one study which examines the effect of haemosporidians on fuel deposition rate and fuel load in a population of population of migratory blackcaps Sylvia atricapilla in Loza lagoon, northern Iberia. Fuel deposition rate is defined as method that determines bird migration strategies. Blood samples were taken from recaptured birds and were analyzed to determine haemospiridian content. The results revealed that these birds' mass deposition rate, fat score and body mass remain the same if compared with non-infected birds. They suggested that infected birds are unable to migrate south from their breeding areas in central and northern Europe.

This article focuses on a study which explored environmental correlates of among-population phenotypic variation in Dipper morphology throughout Iberia. The study used a number of abiotic environmental factors including river slope, altitude, mean temperatures, and the amount of annual precipitation. Hierarchical Linear Mixed Models (HLMM) were also utilized to examine the effect of abiotic factors on biometrics. Results of the study showed that there was no correlation between age and tarsus length. It also found that the abiotic effect disappeared for relative and absolute wing length.

Capsule Fuel load is correlated with fuel deposition rate; stopover duration is affected by arrival fuel load. Aims To determine the stopover duration, fuel management and flight ranges at departure of Blackcaps stopping over in northern Spain. Methods Systematic mist-netting and ringing allowed the use of mark-recapture Cormack-Jolly-Seber models for the estimation of stopover duration. Trapped birds were measured and weighed in order to estimate mass gain. FLIGHT software was used to estimate flight ranges. Results Stopover duration ranged from 3.6 to 13.6 days, and was negatively correlated with arrival body mass (assessed by body mass at the first capture event). On average, arrival body mass was 1 8.4 g, whilst body mass at departure was 19.8 g. No significant differences in arrival body mass and departure body mass were observed between age or sex classes. Mass deposition rate did not differ between age or sex classes (mean = 0.20 g/day). Birds recaptured one day after the first capture event lost mass, whilst recaptures from the second day onwards had a mean gain of mass; mass was observed to increase linearly with the stopover duration. Mass deposition rate was positively correlated with departure body mass. Finally, with a mean departure body mass of 19.8 g, a Blackcap stopping over in northern Spain should be able to fly up to 1100 km. Conclusions Stopover duration assessed by Cormack-Jolly-Seber models was longer than that observed in birds recaptured more than once (`minimum stopover duration'). Stopover was longer for birds arriving with less fuel. The positive relationship between departure body moss and mass deposition rate suggests a time-minimizing strategy. The lack of difference in fuel deposition rate between age and sex classes suggests a relatively abundant food supply at the study site, but other explanations might also account for the lack of age and sex differences, for example if competition for food was not determined by social hierarchies but by scramble competition. Departing fuel load would allow these birds to arrive at their wintering areas in southern Spain under still-air conditions, without needing to refuel. [ABSTRACT FROM AUTHOR]

Simple Summary: Alteration of natural habitats due to urbanization is an increasing concern worldwide. Some species, including owls, can exploit this novel environment, although the consequences at the population level have not been described. In this study, we analyze the effect of different urban variables on tawny owl (Strix aluco) population abundance. At the local scale, forest and urban cover, as well as the clumpiness index, affected tawny owl abundance. At the landscape scale, its abundance decreased in complex-shaped urban patches and when distance between them was greater. Urban habitats do not substitute natural habitats in terms of abundance, but the species can easily colonize patchy urban habitats. Natural habitats are being altered and destroyed worldwide due to urbanization, leading to a decrease in species abundance and richness. Nevertheless, some species, including tawny owls, have successfully colonized this novel habitat. Consequences at the population level have not been described; thus, our main objective was to describe the effects that urban structure have on the tawny owl population at local and landscape levels. Data were obtained from 527 survey points over 7 months in a large-scale owl survey in the Basque Country (northern Spain) in 2018. At the local scale, the interaction between forest and urban cover affected tawny owl abundance, the optimum being in medium forested areas. The interaction between urban cover and clumpiness index (urban patch distribution) showed a generally negative effect. At the landscape scale, its abundance decreased in complex-shaped urban patches and when distance between them was greater. In conclusion, at the local scale, when a minimal forest structure is present in urbanized areas, the species can exploit it. At the landscape scale, it prefers smaller urban towns to cities. Thinking ahead, the current tendency toward "green capitals" should benefit tawny owl populations. [ABSTRACT FROM AUTHOR]

In colonial seabirds, the nest substrate that is available and, in particular, the vegetation cover around the nest, are important environmental factors that drive an individual's nesting selection process and, ultimately, reproductive performance. Using data collected during three consecutive years in a Yellow-legged Gull Larus michahellis colony from the Bay of Biscay, Spain, we tested whether clutch size, egg volume, and hatching success covaried with the proportion of vegetation cover around nests. We found no effect of vegetation cover on breeding performance. Laying date showed a positive effect on egg volume and a negative effect on hatching success and the number of hatched eggs. Egg volume tended to be smaller in 2020 compared to 2018 and 2019, and hatching success decreased through the sampling period, with the lowest hatching success occurring in 2020. Our findings agree with a previous study in which vegetation had no or unclear effects on breeding performance in Yellow-legged Gulls; however, they contradict other seabird studies that found a positive correlation between the two variables. The role of vegetation on breeding performance could vary not only between gull species, but also geographically, with ecological drivers such as intra- and interspecific interactions and climate playing key roles in observed differences. Finally, the use of egg volume and hatching success as proxies for breeding output could be used for the long-term monitoring of the relationship between breeding performance and factors such as landfill management, fishing, or climate change in the Yellow-legged Gull and other gull species. [ABSTRACT FROM AUTHOR]

Carotenoid-based ornamentation can vary greatly among individual birds of the same population. This variability might consider the timing and duration of moult. Crossbills (genus Loxia) show large variation in their colour patterns, ranging from dull yellow to red. Thus, they provide an excellent avian model for testing whether the timing and duration of their moult are associated with their dominant colour patterns. Using a dataset of more than 1900 crossbills captured in the Pyrenees (Spain), we observed that individuals with red feathers started their primary moult early, while those with yellow feathers started moult on an average of 18 days later. We also found that yellow crossbills were more likely to suspend moults (i.e. temporally interrupt moult), postponing a part of the moult until September. These differences in the moulting process may be related to plumage colour, which reflect individual condition. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor about peritonitis involving Capnocytophaga ochracea.

Carotenoid-based ornaments are often considered reliable (honest) individual condition signals because their expression implies physiological costs unaffordable for low-quality animals (handicap signals). Recently, it has been suggested that efficient cell respiration is mandatory for producing red ketocarotenoids from dietary yellow carotenoids. This implies that red colorations should be entirely unfalsifiable and independent of expression costs (index signals). In a precedent study, male common crossbills, Loxia curvirostra, showing a red plumage reported higher apparent survival than those showing yellowish-orange colors. The plumage redness in this species is due to ketocarotenoid accumulation in feathers. Here, we correlated the male plumage redness (a 4-level visual score: yellow, patchy, orange, and red) and the body morphology in more than 1,000 adult crossbills captured in 3 Iberian localities to infer the mechanisms responsible for color evolution. A principal component analysis summarized morphometry of 10 variables (beak, wing, tarsus length, etc.). The overall body size (PC1) and the length of flight feathers regarding body size (PC3) showed significant positive relationships with plumage redness. Plumage redness was barely correlated with bill shape measures, suggesting no constraint in acquiring carotenoids from pine cones. However, large body sizes or proportionally long flying feathers could help carotenoid acquisition via social competition or increased foraging ranges. Proportionally longer flight feathers might also be associated with a specific cell respiration profile that would simultaneously favor flying capacities and enzymatic transformations needed for ketocarotenoid synthesis. Such a phenotypic profile would agree with the hypothesis of ketocarotenoid-based colors acting as individual quality index signals. [ABSTRACT FROM AUTHOR]

Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite- and GPS-tracked gull and tern populations belonging to 14 species in Europe and North America, we examined the occurrence and factors explaining prospecting by actively breeding birds. Prospecting in active breeders occurred in 85.7% of studied species, across 61.3% of sampled populations. Prospecting was more common in populations with frequent inter-annual changes of breeding sites and among females. These results contradict theoretical models which predict that prospecting is expected to evolve in relatively predictable and stable environments. More long-term tracking studies are needed to identify factors affecting patterns of prospecting in different environments and understand the consequences of prospecting on fitness at the individual and population level. [ABSTRACT FROM AUTHOR]

Carotenoid staining has been repeatedly shown to serve as a sexually selected individual quality signal. In different species, individuals that show brighter carotenoid-based signals have been found to have superior feeding abilities, recover faster from disease, and generally enjoy better body condition. In the common crossbill (Loxia curvirostra), the colour has also been related to the different populations, with northern and central European populations being described as redder than those in the Mediterranean region. A study in the Pyrenees showed that long-winged individuals had lower apparent survival, and the proportion of red individuals was higher in long-winged birds, concluding that they could be nomadic birds (that travel long distances). A priori, if the red crossbills are more mobile than the yellow and orange ones, their apparent survival will be lower. However, in our study, red males showed a greater survival than males of other colours and almost double than that of the yellow ones. These results suggest that red coloration is linked to higher quality individuals regardless of their mobility. [ABSTRACT FROM AUTHOR]

Background: Philopatry rate is one of the main factors shaping population dynamics in colonial seabirds. Low rates of philopatry are linked to populations with high dispersal, while high rates are linked to populations with a very high spatial structure pattern (i.e., metapopulations). The Cantabrian Yellow-legged Gull (Larus michahellis) population is considered to be resident, with relatively low dispersal rates. Precise estimations of its philopatry rates are however still lacking. Here, we aimed to estimate philopatry rates in the main Yellow-legged Gull colonies of the province of Gipuzkoa, in the southeastern part of the Bay of Biscay. Methods: We analysed 734 resightings, during the breeding season at the colonies of Getaria, Santa Clara and Ulia, relative to a total of 3245 individuals ringed at birth in these same colonies during a period of 13 years. These data were analysed using Multi-State Recapture models in MARK. Results: After controlling survival and resighting probability, the average dispersal rate among colonies was 4% (± SD = 2%) when individuals are immature, decreasing to 1 ± 1%) for adult breeding gulls (i.e., philopatry rate was 99%). Annual survival rates were assessed to be 0.27 ± 0.02 for birds in their first year of life and 0.87 ± 0.01 for older individuals. The probability of observing immature birds in the colonies was 0.08 ± 0.01, as compared to 0.21 ± 0.02 in adult birds. Conclusions: We obtained evidence of extremely high local philopatry rates, clearly within the upper limit found in gulls. A high philopatry favour a speciation in these species who are vulnerable to obtain the main food source (landfills and fishing discard) which are transforming under new ecological process. [ABSTRACT FROM AUTHOR]

The Bay of Biscay is an important non-breeding area for some Palaearctic gull species and populations. The aim of this work is to describe the spatial and temporal distributions of non-breeding gulls in the Bay of Biscay, and to identify their major areas of origin. With that goal, we analysed 6773 live sightings of colour-ringed gulls within the southeastern part of the Bay of Biscay during the 20 years 2000–19, relating to 2552 individuals of 10 species. Their distribution along the coast was not homogeneous, with numbers peaking in most cases from November to February, though some species were observed to peak around midsummer. Their origins comprised a wide geographical area encompassing western and eastern Europe; overall, the species can be divided into four groups by origin: northwestern France with Britain and Ireland, central western Europe (with a centroid in the Benelux region), eastern Europe, and the western Mediterranean. [ABSTRACT FROM AUTHOR]

Wildlife conservation policies directed at common and widespread, but declining, species are difficult to design and implement effectively, as multiple environmental changes are likely to contribute to population declines. Conservation actions ultimately aim to influence demographic rates, but targeting actions towards feasible improvements in these is challenging in widespread species with ranges that encompass a wide range of environmental conditions. Across Europe, sharp declines in the abundance of migratory landbirds have driven international calls for action, but actions that could feasibly contribute to population recovery have yet to be identified. Targeted actions to improve conditions on poor-quality sites could be an effective approach, but only if local conditions consistently influence local demography and hence population trends. Using long-term measures of abundance and demography of breeding birds at survey sites across Europe, we show that co-occurring species with differing migration behaviours have similar directions of local population trends and magnitudes of productivity, but not survival rates. Targeted actions to boost local productivity within Europe, alongside large-scale (non-targeted) environmental protection across non-breeding ranges, could therefore help address the urgent need to halt migrant landbird declines. Such demographic routes to recovery are likely to be increasingly needed to address global wildlife declines. [ABSTRACT FROM AUTHOR]

Studying the individual or population response of species to variations in weather is gaining impetus due to increased interest in quantifying the effect of global change on biodiversity. Our goal here was to test the role of meteorological conditions (particularly extreme weather) on the activity budget of a generalist seabird species during its breeding season. To this end we used data from GPS-tracked adult yellow-legged gulls (Larus michahellis). Precipitation and wind had a significant impact on spatial use, reducing foraging distances and forcing gulls to spend a longer period within the colony and promoting a change in habitat use. The results suggest that rainfall and wind forced breeding gulls to desist from the area and habitats used under favourable weather, which might affect chicks' food provisioning. In a future with increasing rainfall and a higher number of extreme bad weather events, investigation should be conducted to establish the extent to which reduction in spatial use may negatively impact reproduction and, hence, demography. [ABSTRACT FROM AUTHOR]

Suspended moult is a relatively common phenomenon in birds, but it has remained relatively ignored for a long time in studies dealing with moulting process. Furthermore, the new and increasing number of models used to estimate moult duration systematically omit the fact that suspended moults can occur and that they significantly alter parameter estimates. Taking suspended moults into account is critical to obtain reliable moult-associated parameter estimates, which is fundamental given the demographic and evolutionary consequences of moult in birds. The main goal of this work is to develop a standardised method useful for characterising the main moulting parameters (such as the duration and starting date) of bird species that perform suspended moults. Additionally, with the aim of delving into our understanding of when and why suspended moults happen, we study their relationship with the occurrence of second breeding attempts in summer. We used data obtained from a Red Crossbill population in the Pyrenees during a period of 17 years. We observed that the percentage of crossbills undergoing suspended moult was approximately 50% during summer (July–August) and that moult suspension ultimately gives rise to a lengthened moulting period. Underhill–Zucchini models assume a time-linear replacement of feathers, overestimating the moult duration. Based on these same modelling approaches, we proposed a method to calculate the real moult duration after removing the time during which the moult was suspended. We also obtained evidence supporting the idea that crossbills suspend their moult as a strategy that could increase their breeding output in summer. The method proposed here can be used as a tool for working with species that undergo suspended moults. [ABSTRACT FROM AUTHOR]

The management of game species relies on robust estimates of hunting-related mortality. A relative measure of this mortality can be obtained by comparing survival estimates of animals across similar areas with different hunting pressures. We conducted live recapture-dead recovery analyses on wintering Eurasian Woodcocks Scolopax rusticola (hereinafter "Woodcock") in provinces of Gipuzkoa (GIP) and Álava (ALA), two neighboring regions of northern Spain. The two regions have a similar number of hunting licences issued on a per day basis, but while hunting is limited to 3 days per week in ALA, in GIP it is allowed on a daily basis, resulting in a ca. 50% longer period of exposure of game species to hunting-related mortality here. We used a model based on monthly survival estimates to test whether the mortality of Woodcock varied between the two regions. Mean (± SE from a time-constant model) annual survival of Woodcocks was estimated to be 0.37 (± 0.04) and 0.56 (± 0.04) in GIP and ALA, respectively. If we assumed that this difference was only due to the longer period of exposure to hunting, mortality was increased by ca. 10% per additional day of hunting per week. Moreover, we also found that survival was positively associated with temperature in one of the study zones (ALA), suggesting that a high hunting pressure can override the effect of climate-dependent fluctuations. However, further research into fecundity and dispersal is necessary to assess the viability and sustainability of the wintering Woodcock populations under the current hunting regimes in these two zones. [ABSTRACT FROM AUTHOR]

The type of ring (i.e. its colour combination: the colour of the alphanumeric characters and the base colour of the ring) used in population dynamics studies could have an effect on parameters such as resighting probability ( p); for instance, we might expect a lower p value when using rings with white characters than when using rings with dark characters. We performed an experiment using two types of colour rings (white or black characters on a dark base) in Yellow-legged Gulls in order to test our hypothesis. To do this, we used Cormack-Jolly-Seber (CJS) models incorporating variation in p among the birds. We obtained no evidence supporting an effect of type of ring on either survival or p. [ABSTRACT FROM AUTHOR]

Methylmercury (MeHg) is the most bioavailable and toxic form of the globally distributed pollutant Hg. Organisms of higher trophic levels living in aquatic ecosystems have potentially higher concentrations of MeHg. In this work, we analysed both MeHg and inorganic Mercury (Hg(II)) concentrations from dorsal feathers of chicks from ten colonies of Yellow-legged Gull (Larus michahellis) in the south-eastern part of the Bay of Biscay. Overall, we detected a high mean MeHg concentration that, however, differed among colonies. Additionally, based on stable isotopes analysis (δ13C and δ15N) and conducting General Linear Mixed Models, we found that chicks which were mostly/mainly fed with prey of marine origin had higher levels of MeHg. We propose Yellow-legged Gull as a reliable biomonitor for Hg species, as it is easy for sampling and in compliance with the Minamata convention on Mercury. • Methylmercury (MeHg) is the most bioavailable and toxic form of Hg. • MeHg and Hg(II) concentrations were analysed from chicks' feathers of Larus michahellis. • A high mean MeHg concentration was detected that, however, differed among colonies. • Chicks which were mostly/mainly fed with prey of marine origin had higher levels of MeHg. • Yellow-legged Gull is proposed as a reliable biomonitor for Hg species. [ABSTRACT FROM AUTHOR]

Carotenoid-based ornaments are often considered reliable (honest) individual condition signals because their expression implies physiological costs unaffordable for low-quality animals (handicap signals). Recently, it has been suggested that efficient cell respiration is mandatory for producing red ketocarotenoids from dietary yellow carotenoids. This implies that red colorations should be entirely unfalsifiable and independent of expression costs (index signals). In a precedent study, male common crossbills, Loxia curvirostra , showing a red plumage reported higher apparent survival than those showing yellowish-orange colors. The plumage redness in this species is due to ketocarotenoid accumulation in feathers. Here, we correlated the male plumage redness (a 4-level visual score: yellow, patchy, orange, and red) and the body morphology in more than 1,000 adult crossbills captured in 3 Iberian localities to infer the mechanisms responsible for color evolution. A principal component analysis summarized morphometry of 10 variables (beak, wing, tarsus length, etc.). The overall body size (PC1) and the length of flight feathers regarding body size (PC3) showed significant positive relationships with plumage redness. Plumage redness was barely correlated with bill shape measures, suggesting no constraint in acquiring carotenoids from pine cones. However, large body sizes or proportionally long flying feathers could help carotenoid acquisition via social competition or increased foraging ranges. Proportionally longer flight feathers might also be associated with a specific cell respiration profile that would simultaneously favor flying capacities and enzymatic transformations needed for ketocarotenoid synthesis. Such a phenotypic profile would agree with the hypothesis of ketocarotenoid-based colors acting as individual quality index signals., (© The Author(s) 2022. Published by Oxford University Press on behalf of Editorial Office, Current Zoology.)

The dynamics of wild populations are governed by demographic rates which vary spatially and/or temporally in response to environmental conditions. Conservation actions for widespread but declining populations could potentially exploit this variation to target locations (or years) in which rates are low, but only if consistent spatial or temporal variation in demographic rates occurs. Using long-term demographic data for wild birds across Europe, we show that productivity tends to vary between sites (consistently across years), while survival rates tend to vary between years (consistently across sites), and that spatial synchrony is more common in survival than productivity. Identifying the conditions associated with low demographic rates could therefore facilitate spatially targeted actions to improve productivity or (less feasibly) forecasting and temporally targeting actions to boost survival. Decomposing spatio-temporal variation in demography can thus be a powerful tool for informing conservation policy and for revealing appropriate scales for actions to influence demographic rates., Competing Interests: We declare we have no competing interests., (© 2022 The Authors.)

Crimean-Congo hemorrhagic fever virus (CCHFV) was detected in Spain in 2010. The presence of CCHFV in Hyalomma marginatum ticks from migratory birds passing through Morocco during the spring migration strengthened the hypothesis of the arrival of infected ticks transported by birds to the Iberian Peninsula. Furthermore, Hyalomma species are vectors of bacterial infections such as spotted fever rickettsioses. CCHFV and Rickettsia were screened in Hyalomma ticks from Spain attached to patients (n=12) and birds (n=149). In addition, Rickettsia was investigated in 52 Hyalomma ticks from Morocco (previously reported as CCHFV-infected). No sample collected in Spain showed an infection with CCHFV. Two ticks removed from patients (16.7%), as well as 47 (31.5%) and 4 (7.7%) from birds, collected in Spain and Morocco respectively, were infected with Rickettsia aeschlimannii. Rickettsia sibirica subsp. mongolitimonae was also found in 2 ticks from birds collected in Spain (1.3%). The risk of CCHFV-infected ticks attached to migratory birds to reach the North of Spain is low. This study corroborates the presence of R. aeschlimannii in Spain and Morocco, and supports that H. marginatum can be a potential vector of R. sibirica subsp. mongolitimonae in the Iberian Peninsula., (Copyright © 2016 Elsevier GmbH. All rights reserved.)