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

The food available in open-air landfills, one of the most common predictable anthropogenic food subsidies (PAFS), can have a profound impact on animal biodiversity. Understanding how and to what extent PAFS affect wildlife is crucial for a sustainable management of resources. Most large gulls behave as opportunistic foragers and constitute a good avian model to analyze the effect of PAFS reduction on animal populations. Using individual data from a yellow-legged gull population of the Basque coast (northern Iberia) collected over a 15-year period, we estimated survival and reproductive parameters and used them to parameterize an age-structured population model to explore the effects of the local landfill closure. Local survival probability declined with time as a consequence of the progressive closure of the local landfill sites. The top-ranked models included a quadratic function of time, suggesting an acceleration of mortality during the later years, especially in juveniles, while survival in adults was linear. An effect more pronounced in first year birds than in older birds. Population models predict a decrease of the population and confirmed a greater sensitivity of the population growth rate to adult survival probability. Overall, our results suggest that the reduced carrying capacity of the system resulted after landfill closures have caused a population decline which is expected to continue in the near future. [ABSTRACT FROM AUTHOR]

The dynamics of migratory populations at wintering quarters can inform on population state and size because these areas act as demographic funnels, assembling birds from different origins. Previous evidence on survival probability of woodcock Scolopax rusticola wintering in northern Spain suggested a high harvesting pressure, but whether this pressure is causing a decline of woodcock occurrence at wintering quarters is still to be assessed. We used data from 3411 surveys conducted during the winter at 434 selected grasslands in the Gipuzkoa region, Northern Spain, to investigate the dynamics of woodcock occurrence probability, conditional on detection, over a period of 10 years (2009–2019). A 47% of the variation in woodcock occurrence within and across winters was explained by the monthly average minimum temperature. The remaining variation was due to a marked increase during the winters 2016 and 2017, contrary to the progressively decreasing values detected in previous years. At present, these abrupt yearly fluctuations prevent clear predictions on woodcock presence in the Gipuzkoa region. Future studies should explore woodcock occurrence probability according to scenarios of climate and habitat changes. [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]

Volunteer-based (i.e., citizen science) monitoring schemes constitute a basic piece for the long-term monitoring of bird populations. This work aims to determine whether we can reduce the sampling effort, in terms of number of sampling journeys per yearly campaign, of a long-term breeding bird monitoring ringing scheme in Spain. With that goal, we test to what extent a progressive decreasing number of journeys (from the original effort of seven visits in a season to four visits) will have an impact on indices of adult abundance and/or productivity. Reducing the number of visits did not affect the estimate of abundance of adults, either if we consider a full-period population change index which takes into account the numbers of the last survey year in relation to the first one in the series, or if we consider annual trends (with a yearly index which is referred to a reference value—1—fixed for the first survey year). By contrast, the estimation of productivity was severely affected by a reduction of the sampling effort. We attribute this result to the fact that juveniles were captured late in the season and, therefore, eliminating the last sampling journeys produced biased estimates. It is proposed that the program can reduce the effort from seven to six visits (i.e., one visit per fortnight from May to July) with little impact on the estimation of abundance and productivity. Additionally, the program may admit sites with a sampling effort of four visits, from May to June, useful to estimate trends on abundance of adults and their survival rates (but not on productivity). With this dual option, we expect to increase the spatial coverage of the program and the robustness and representativeness of at least two of the indices calculated through the program, since we might both increase the number of participants (i.e., sites) and the type of habitats covered. [ABSTRACT FROM AUTHOR]

Artificial food subsidies like landfills generate very strong impacts on animal ecology and spatial behavior. Landfills indeed have been considered to be one of the most influential factors explaining the very fast recovery of many colonial waterbird populations worldwide, as documented for the white stork Ciconia ciconia. More recently, the increase of rice fields in some regions have also been argued to be part of an influencial process underlying the spatio-temporal distribution patterns of this species over many areas in southern Europe. It remains unknown whether these two habitat factors play an important role at explaining the spatial distribution pattern of the white stork and, more particularly, whether colony funding or colony size is dependent on them. Using data from a census conducted in 2018, we aimed to assess the effect of distance to a landfill or to rice fields, among other habitat factors, on the breeding colony size of a white stork population in northern Spain. Larger colonies were more likely to appear in trees or cliff, but less likely in buildings or other artificial substrates. They were also significantly more likely with decreasing distance to landfill, and when the habitat was dominated by dry cropland and meadows close to water bodies. Rice fields did not seem to have any significant effect. Our findings fit with those from other regions in Europe, and highlight the effect landfills have on population dynamics and spatial ecology for those species which are able to feed on this type of food subsidy. Our results also show that the main habitat cover over large geographic scales still plays a role independently of landfills. The European agricultural policies associated with the type and management of crops, and the Common Agricultural Policy in particular, will still have a decisive role for the species. [ABSTRACT FROM AUTHOR]

The increase of the tourism and urbanization of vast areas of dunes and beaches has been accompanied by an increase in the level of disturbances to many shorebirds, especially on those species which depend on such habitats to breed. The European Kentish plover (Charadrius alexandrinus) population is declining, also in the Canarian archipelago, one of the most important touristic destinations worldwide. Using data from an intense monitoring program on Lanzarote Island and the nearby La Graciosa islet (hereafter, both referred as Lanzarote), we aimed to (1) estimate the breeding output and survival and (2) use these parameter estimates to build a population model to assess the long-term growth rate of the population and evaluate, accordingly, its conservation status. Our studied population presents a relatively high breeding success although, thereafter, the first-year apparent survival is low. Even though adult apparent survival rates are reasonably high, these seem insufficient to compensate for the low survival rates of the first-year birds. In this sense, we found a negative growth rate according to a population model estimating an annual loss equivalent to 20% (95% confidence interval: 6–35%). Local studies to account for the effects of human disturbance caused by tourist industry on survival, breeding rates, and demography are required to develop precise conservation actions for the Kentish plover population in Lanzarote. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature 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.)

Transients can have a severe impact on demographic parameter estimates. For instance, the use of visual counts or number of captures at a ringing station to assess indices of abundance may result in biased over-estimates due to the presence of transients. With the aim of contributing to understand transient dynamics within the Eurasian breeding passerines, we used data collected at a ringing station (2010–2018) in a reed bed area of northern Spain designed to sample breeding reed warblers Acrocephalus scirpaceus. Specifically, we tested for the effect of season on the proportion of transients and explored for correlations of rainfall regimens at both the winter and breeding quarters on annual fluctuations of the proportion of transients. The proportion of transients was not constant across the season; it showed relatively small values until mid-June, coinciding with arrivals from Africa and the peak of the breeding period, and then increased very steeply (means > 60%) already in July, with even ca. 90% of transients captured during the second half of July, coinciding with an influx of birds that would be already passing through the area en route to winter quarters in Africa. Analyses to estimate population trends of breeding reed warblers should take this circumstance into account; otherwise, models may show odd patterns, due to a mixture of local and non-local population that might show dissimilar demographic trends. Limiting data analyses to the breeding sub-period having a lesser amount of transients is recommended. Annual fluctuations in the proportion of transients did not correlate with any of the rainfall values in Africa (winter quarters) or meteorological conditions in Europe (NAO index; rainfall values at a local level), though it might be that we did not choose the appropriate variable/period/location combination. Our data set was relatively small; hence, this may hamper us to detect weak linear trends. Future research should contribute to answer this question and deep into the factors driving transience dynamics in bird populations. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature 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.)

Copyright of Journal of Ornithology is the property of Springer Nature 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.)

Common Crossbill ( Loxia curvirostra) populations are dependent on specific key conifer species for their primary food supply, but many of these conifers standardly show irregular cone crop production. Consequently, the species has evolved a nomadic behavior, breeding in areas with a high crop production in given years. Northern European crossbills mostly forage on Norway Spruce ( Picea abies) and migrate along a northeast-southwest gradient across Europe. In contrast, crossbills from Spain were considered to be resident until recent studies on crossbill populations in the Pyrenees showed that a fraction of the population may also migrate. The type of movements of these Spanish birds, however, remains virtually unknown. The aim of our study was to resolve the question of whether these birds displace on a small local scale or whether they actually move to a distinct non-breeding area for part of the annual cycle. We tracked 14 male Common Crossbills from the Pyrenees with light-level geolocators for an entire year. Our results suggest that these birds were resident; only one bird may have shown a west-east movement of up to 200 km along the Pyrenean axis. We conclude that movement of the Common Crossbill from the Pyrenees may predominantly consist of relocation to nearby mountain ranges in Iberia or vertically in altitude. We expect that such small-scale movements have implications for population dynamics, and we recommend further research with telemetry to resolve the details of this small-scale movement. [ABSTRACT FROM AUTHOR]

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

The illegal hunting of wild birds is still today a major threat to the conservation of biodiversity on a global scale. This activity jeopardizes the survival of several migratory species. Our aims in this work were to (1) determine the spatial and temporal distribution of illegal hunting activities affecting bird species with regard to the location of fixed hunting posts in particular, and (2) identify the most affected species in Gipuzkoa (north of Spain), situated in a bottleneck area within one of the main routes of migration between Europe and Africa. All of our data came from birds with firearm injuries that were admitted to the Gipuzkoa Wildlife Rehabilitation Center (WRC). Over a period of 8 years (2006-2013), 421 birds belonging to 53 species were registered. The number of shot birds was found to be greater in more highly populated areas and during the months coinciding with hunting periods. Moreover, shot birds were recovered close to fixed hunting posts, suggesting that the illegal shooting of birds took place near or directly from these posts. Although the figures were not comparable to the high numbers of migrants shot annually in some other southern European areas, our results show that, even in small areas like Gipuzkoa, increased levels of protection are necessary. [ABSTRACT FROM AUTHOR]

Knowledge of spatio-temporal animal distribution patterns is one of the main chapters of wildlife research, not only due to its biological and ecological importance but also its usefulness in the conservation and management of animal populations. Iberia is a target wintering region for the Eurasian woodcock ( Scolopax rusticola). The aim of the present work is to determine which factors shape woodcock distribution patterns during the winter period. To ascertain this, we used data collected over three consecutive years (winter of 2010/2011-2012/2013) in a region from northern Iberia (Gipuzkoa). Woodcock numbers ( W) were modeled using generalized linear mixed models. The models that best fitted our data included a significant effect of latitude, land uses, sampling year, and type of meadow on W (once weighted for the number of visits and the area of each meadow). Overall, W tended to be lower in sites from southern Gipuzkoa, in those areas where there was a higher proportion of tree plantations, in grazed mountain pastures, and during the winters of 2011 and 2012 in relation to 2010 (mean ± SD values in 2010, 0.4 ± 0.5 woodcocks/ha; 2011, 0.2 ± 0.3 woodcocks/ha; 2012, 0.2 ± 0.4 woodcocks/ha). Part of the observed variance was due to the 'year' effect, which could include several potential explanatory variables. Future research should try to add variables such as year-associated meteorological conditions, at both breeding and non-breeding quarters. Locally, a mosaic of some forest/woodland with abundant meadows would allow numbers of woodcocks to reach an optimum within the region. Moreover, the species was more abundant in the north; hence, the zones close to the coast had more importance from a conservation standpoint. [ABSTRACT FROM AUTHOR]

The development of increasingly small devices for the satellite tracking of small birds allows us to explore aspects of avian migration that have never been studied before. Here, we provide the results of using 12- and 9.5-g platform transmitter terminals (PTTs) to track game birds of 300-385 g. Attaching PTTs to 20 Woodcocks ( Scolopax rusticola), wintering in Spain from 2006 to 2012, allowed us to explore (1) migration strategies (timing, velocity and stopovers), (2) the identity of the breeding grounds; (3) inter-year site fidelity to wintering grounds. We provide details of the route, speed and timing of migration and the location of remote breeding sites that were unknown prior to this study. The departure from winter quarters (median date) was completed by 20 March. The spring migration period lasted 40 days, and our birds were found to travel from >5,000 to >10,000 km, with a mean total migratory speed (i.e., including stopovers) of 170 km/day. Woodcocks followed fairly direct routes of migration. Stopover duration tended to be shortened when birds were closer to their breeding areas, which were located further east than previously stated. The only bird that provided long-term data (>1 year) was observed to return to the same wintering area, suggesting high winter site fidelity. The use of small PTTs opens new research lines related to the study and management of small to medium-sized migratory birds. [ABSTRACT FROM AUTHOR]

In birds, spatial segregation between age or sex categories during the non-breeding period is a common phenomenon. The main single-factor hypotheses that have been stated to explain this are: (1) body-size variations (that result in more or less cold tolerance) interact with local climate, which promotes age- or sex-associated distributional optima; (2) the dominant age or sex monopolizes high-quality areas; and (3) the age or sex overwintering closer to breeding quarters does so due to the benefits of earlier arrival at the breeding quarters. Southern European countries host millions of birds from northern Europe during the winter period each year. In this work, we aimed to determine the ultimate causes (geographic location and distance to obligate migratory pathways, temperature and land use as a surrogate for food availability) explaining spatial segregation of Reed Buntings ( Emberiza schoeniclus) by age and sex in winter. We used data from 38 sampling points across Iberia during the winter of 2011-2012. Reed Bunting abundance did not fit any of our possible models better than the null model, so we were unable to predict bird numbers across Iberia. Moreover, males were found to be predominant at sites close to presumably obligate migratory pathways (western/eastern Pyrenees). Body mass was higher in first-year birds and males, and tended to increase with distance to obligate migratory pathways, land use (in particular with a decreasing proportion of open habitats and urban areas), increasing minimum temperature, and decreasing mean temperature. Our data suggest that the increase in the proportion of males close to obligate migratory pathways is associated with the advantage to males in wintering as close as possible to breeding quarters. [ABSTRACT FROM AUTHOR]

Specialist foragers depend on specific prey commonly associated with limited habitat, which is often patchily distributed. Understanding how specialists use habitat patches is important to their conservation. Crossbills ( Loxia spp.) are one of the best examples of a foraging specialist, because they exploit population-specific conifer species. In this work, we used morphology and stable isotopic analyses (δH) to test the use of two different key conifer species ( Pinus spp.) by crossbills. This study was conducted in Spain to test whether a small patch of Aleppo pine ( P. halepensis) from the Ebro Valley hosted native, resident common crossbill ( L. curvirostra) populations or, by contrast, if it was used just as a 'stopover' or a passage site between the two main mountain ranges situated to the north and south of this valley, which is mostly occupied by Scots pine ( P. sylvestris). Crossbills caught at the Ebro Valley used this zone only temporarily, thus supporting the lack of a stable, strictly resident population. Morphological and isotopic analyses revealed that these birds were likely to belong to an Aleppo pine-associated population, and likely not to Scots pine crossbills moving between the Pyrenees and the Iberian System. Therefore, we observed evidence supporting high foraging specialization and population-specific use of key conifer resources in Spain. This work highlights the usefulness of combining morphological and stable isotopic analysis to infer the origin and possible movement patterns of crossbill populations. [ABSTRACT FROM AUTHOR]

Seasonal fluctuations in marine prey availability around breeding colonies are one of the major factors affecting resident behaviour in seabirds. This is particularly applicable to large gulls ( Larus spp.). The effect of refuse management on large gulls has been studied chiefly in relation to breeding dynamics, but it is less understood with regard to movement patterns. Our aim was to test whether the closure of one large dump and the use of falconry to deter gull access to two others, within the southeastern Bay of Biscay area, affected the foraging distance of local yellow-legged gulls ( Larus michahellis). During a period of seven consecutive winters between 2005 and 2011, the proportion of gulls that moved less than 50 km from their natal site was 70 %. However, during the winter of 2010, when they were deterred from accessing refuse tips within the region, gulls were found to travel longer distances. This result was explained neither by a decreasing survey effort near colonies nor by a decrease in apparent availability of marine prey, thus supporting the hypothesis that refuse management within the region influenced the movement patterns of local gulls. [ABSTRACT FROM AUTHOR]

The impact of nomadism on animal population dynamics (e.g. survival) is poorly understood. This factor is not inconsequential because our current view on animal survival rates could suffer from biases if it is ignored. The degree of nomadism in Common Crossbills ( Loxia curvirostra) is reported to differ population-specifically, and thus they constitute a good model for the study of survival in nomadic species. Southern Europe hosts resident birds, probably also local vagrant birds and non-local, vagrant, northern European Crossbills. The impact of vagrants on the estimation of apparent survival rates has never been determined in areas where Crossbills have been reported as resident. We hypothesise that transients (birds for which survival from year t to year t + 1 is zero) will be detectable if a majority of vagrants remain at a particular site for just a few months. Alternatively, if vagrants remain for longer, transients will be absent by definition, so apparent survival estimation will be lower than would be if transients did not exist. As wing length in vagrants is commonly longer than in residents, we can expect a negative effect of wing length on survival, as long-winged (vagrant) Crossbills emigrate from the area after a few years, thus demonstrating lower apparent survival rates than resident, local birds on a local scale. Alternatively, if vagrants have a negligible impact on the estimation of local apparent survival rates (i.e. if residents clearly outnumber vagrants), we should not detect transients nor find any effect of wing length on survival. To test this hypothesis, we used data collected over a period of 16 years at a site located in a Scots pine ( Pinus sylvestris) forest in northern Iberia. Capture-recapture data were analysed with Cormack-Jolly-Seber (CJS) models. Although transients were not detected, the CJS models showed that survival was negatively affected by wing length. Our results support the hypothesis that vagrants occurred in the area for more than 1 year before subsequently disappearing, and that their presence has a strong impact on local survival estimation. Accordingly, if the presence of vagrants is not considered, this can lead to the underestimation of local survival rates of resident Crossbill populations. [ABSTRACT FROM AUTHOR]

Meteorological conditions, fuel load and date in the season can affect the departure decisions among migratory birds. However, it is poorly understood to what extent the departure decisions are more influenced by some parameters in relation to others, and how they interact with each other. We explored here how fuel load, date, rain and wind (measured on the ground and at high altitude, codified as a tailwind component) influenced the departure decisions of migratory Blackcaps ( Sylvia atricapilla) from a stopover site. We used mark-recapture data of 947 Blackcaps collected during the autumn migration period 2005 at a stopover site in northern Iberia, estimating the emigration likelihood with Cormack-Jolly-Seber models, in which we tested for the effect of these four study variables. Best models fitting data showed an additive and positive effect of tailwind and fuel load on the emigration likelihood. [ABSTRACT FROM AUTHOR]

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