Search

Energy infrastructure is expanding at a global scale and can represent a major threat to wildlife populations. Power lines are one of the main sources of human-induced avian mortality due to electrocution or collision, but many species use electricity pylons as a structure for nesting. Pylon nesting results in human-wildlife conflict because it can cause power outages and structural damage to power lines. The white stork (Ciconia ciconia) is a large-size semicolonial species that increasingly nests on pylons, causing growing operational and economic issues to power companies and energy consumers. In this study, the likelihood of problematic pylon use by nesting storks was predicted using a suite of explanatory variables related to the availability of foraging habitat and human disturbance. During a five-year period (2015–2019), we assessed the distribution of stork nests removed from the highly-risky top part of transmission pylons (220–400 kV) by power company technicians in South western Spain. A total of 839 nests were removed from 11% of the transmission pylons (n = 1196) during the study period. Pylon use intensified on pylons located near to landfills, surrounded by high proportion of grassland, and when close to freshwater sources (water body or river) and other occupied pylons. Human disturbance was unlikely to deter storks from using pylons and pylon use increased in urban areas. The approach used here to predict pylon use by nesting birds has applications for both human-wildlife conflict mitigation and conservation purposes where endangered species use human infrastructure. Power companies may use this kind of information to install anti-nesting devices (to reduce power outages and avian mortality or nesting platforms on suitable pylons (to promote pylons use by endangered species), and to account for the likelihood of conflict-prone use of pylons when siting future power lines.

Birds of prey frequently feature in reintroductions and the hacking technique is typically used. Hacking involves removing large nestlings from donor populations, transferring them to captivity, feeding them ad libitum. Potentially, via the hacking method, stress of captivity and disruption of parental feeding may be detrimental. Alternatively, provision of ad libitum food may be advantageous. Although hacking has underpinned reintroduction project successes there has been no research on how the method may affect the health and nutritional status of translocated birds during captivity. We compared blood chemistry data from 55 young White-tailed Eagles, translocated from Norway as part of the species’ reintroduction to Scotland, from sampling soon after arriving in captivity and again (≈ 42 d later) before their release. Numerous significant differences between first and second samples were found, but no significant interactions showed that sexes responded similarly to captivity. According to hematological and biochemical metrics, individuals showed several changes during captivity, including in red blood cell parameters, plasma proteins and white cellular parameters related to the immune system, that indicated improved health status. Captivity with ad libitum food was associated with decreased urea and uric acid values: high values can indicate nutritional stress. Urea values became more normally distributed before release, indicating that ad libitum food had reduced nutritional differences between early nestlings in the season and later ones. Despite plentiful food, both sexes lost body mass before release, suggesting an inherent physiological mechanism to improve flight performance in fledglings. We conclude that hacking improved the health and nutritional status of released eagles which is likely to enable birds to cope with greater costs of exploratory behavior which they may require in reintroduction projects. In this context, we note the absence of survival differences between hacked and wild raptors in previous research.

SummaryAvian electrocutions are a global conservation problem. Power outages associated with electrocutions are problematic for electric utilities focused on delivering reliable electric power. We used contextual data, photographs, line voltage, outage type and assessments of power line components to quantify outage-causing avian electrocutions throughout each of Iran’s 31 provinces. We evaluated records of 222 avian-caused outages involving 235 electrocuted birds in 2018. Of these, 14.5% involved species of conservation concern, and a few (at least eight) sparked fires when the plumage of electrocuted birds ignited and fell into dry vegetation. Most avian-caused outages (96%) involved distribution voltages, and 91% involved phase-to-ground contacts attributable to grounded concrete pylons with grounded steel crossarms. These are the most common type of power line structure in Iran. Insulators were involved in 37% of outage-causing avian electrocutions, fused cutouts 29%, transformers 33%, and midspan collisions 1%. Given the numbers of these components in the electrical system, fused cutouts and transformers were involved in more outage-causing avian electrocutions than expected due to chance. The average body size of electrocuted birds was largest for incidents involving suspension insulators, smaller for birds electrocuted on other insulators, and smallest for electrocutions on fused cutouts and transformers. Given that most avian electrocutions do not cause outages and given the similarity across electric systems in the region, our findings likely indicate a much larger avian electrocution concern throughout the middle east. Retrofitting power line components to reduce avian contacts would reduce impacts to wildlife and improve the electrical system’s reliability, reduce costs associated with unplanned outages, and reduce risks associated power line ignitions of fires.

We used biochemical analyses of blood to quantify nutritional status and a standardized test to measure the response to a novel object (bold-shy test). Our aim was to examine the relationship betwe...

The present biodiversity crisis has led to an increasing number of reintroduction programs, and this conservation method is likely to be increasingly used in the future, especially in the face of climate change. Many fundamental questions in population ecology are focused on the mechanisms through which populations escape extinction. 2. Population viability analysis (PVA) is the most common procedure for analyzing extinction risk. In the use of PVA to model the trajectories of reintroduced populations, demographic values are sometimes taken from other existing wild populations or even from individuals in captivity. 3. Density dependence in productivity is usually considered in viability models, but density‐dependent variation in age of first breeding is usually ignored. Nevertheless, age of first breeding has a buffering effect on population fluctuations and in consequence on population persistence. 4. We simulated the viability of Spanish Imperial Eagle (Aquila adalberti) and Osprey (Pandion haliaetus) populations using data from established and reintroduced populations in southern Spain. 5. Our results show that reduction in the age of first breeding is critical in the success of reintroductions of such long‐lived birds. Additionally, increases in productivity allow populations to growth at maximum rate. However, without considering variation in age of breeding, and the associated increasing overall productivity, reintroduced populations seem nonviable. 6. To ignore density dependence in age of breeding in PVA means that we are seriously limiting the potential of the model population to respond to fluctuations in density, thereby reducing its resilience and viability. Variation in age of first breeding is an important factor that must be considered and included in any simulation model involving long‐lived birds with deferred maturity.

The scientific discipline known as Conservation Biology was established in the early 1980s with the aim of becoming a tool for the management of biodiversity and ecosystems on the planet. The reality today is that there is no consensus among researchers even as to which species and spaces we should protect and how or what are the ecosystem services that we should preserve. I believe that Environmental Thinking is seriously affecting Conservation Biology. The two most influential schools in environmental philosophy thought have been land ethics and deep ecology. In both, especially in deep ecology, we still consider human beings as separate from nature and “bad” from a moral point of view.Intrinsic values beliefs oblige us to avoid any extinction, even if this is a necessary part of the evolutionary process. Both shortcomings are seriously limiting our ability to focus on the real problem. We should overcome the man–nature dichotomy by understanding that we are neither more nor less than a part of it. When we talk about protecting nature, we are actually talking about protecting human–nature habitats, maintaining conditions that make life possible for our species in a world full of opportunities and living beings, including ourselves.

descripción no proporcionada por scopus

Metalliferous mining, a major source of metals and metalloids, has severe potential environmental impacts. However, the number of papers published in international peer-reviewed journals seems to be low regarding its effects in terrestrial wildlife. To the best of our knowledge, our review is the first on this topic. We used 186 studies published in scientific journals concerning metalliferous mining or mining spill pollution and their effects on terrestrial and semi-terrestrial vertebrates. We identified the working status of the mine complexes studied, the different biomarkers of exposure and effect used, and the studied taxa. Most studies (128) were developed in former mine sites and 46 in active mining areas. Additionally, although several mining accidents have occurred throughout the world, all papers about effects on terrestrial vertebrates from mining spillages were from Aznalcollar (Spain). We also observed a lack of studies in some countries with a prominent mining industry. Despite >50% of the studies used some biomarker of effect, 42% of them only assessed exposure by measuring metal content in internal tissues or by non-invasive sampling, without considering the effect in their populations. Most studied species were birds and small mammals, with a negligible representation of reptiles and amphibians. The information gathered in this review could be helpful for future studies and protocols on the topic and it facilitates a database with valuable information on risk assessment of metalliferous mining pollution.

Currently, there is a demand for more energy-efficient lighting sources, however, light emitted by different lighting systems differs in primary properties such as intensity, propagation direction, and wavelength spectrum, among others, and these properties may affect insect light attraction. Despite the energetic benefits of light-emitting diodes (LED) as street light systems, their ecological impacts on insects have not yet been tested on a wide range of taxa. Using an experimental approach, we showed that LED street lights lead to a reduction in the total number of insects captured with light traps in a wide range of families. Coleoptera and Lepidoptera orders were the most sensitive groups to ecological light pollution in the study area. We suggest that LED was the least attractive light system for most of the affected groups both because of its very little emitted short-wavelength light and because of its lower light intensity. We expect that the more and more widespread use of LED lights as a measure to reduce economic costs of outdoor lighting should lead to a lower attraction to street lights in most of the affected insect taxa and to diminish the negative impacts of artificial light attraction on the ecosystems.

The most common ecological response to climate change is the shifts in species distribution ranges. Nevertheless, landscape fragmentation compromises the ability of limited dispersal species to move following these climate changes. Building connected environments that enable species to track climate changes is an ultimate goal for biodiversity conservation. Here, we conducted an experiment to determine if electric power transmission lines could be transformed in a continental network of biodiversity reserves for small animals. We analysed if the management of the habitat located inside the base of the transmission electric towers (providing refuge and planting seedlings of native shrub) allowed to increase local richness of target species (i.e., small mammals and some invertebrates’ groups). Our results confirmed that by modifying the base of the electric transmission towers we were able to increase density and diversity of several species of invertebrates and small mammals as well as number of birds and bird species, increasing local biodiversity. We suggest that modifying the base of the electric towers would potentially facilitate the connection of fragmented populations. This idea would be easily applicable in any transmission line network anywhere around the world, making it possible for the first time to build up continental scale networks of connectivit

Mixed-species colonies occur frequently, especially among seabirds, and may provide mutual benefits among associated species including antipredator advantages. The “protector” species in such associations may provide early warning signals or by aggressively defending their own nests, may expel predators from the area. We explored costs and benefits to Rockhopper Penguins (Eudyptes chrysocome) in relation to offspring production in both monospecific colonies and those mixed with Imperial Cormorants (Phalacrocorax atriceps) at Saunders Island (Falkland Islands), emphasizing differences in predation pressure. We considered behavioral responses of chicks (in creches), as well as differences in their nutritional ` condition, morphometric measurements, and survival compared among different breeding colonies. Our study revealed a paradox: High-quality adult penguins, those arriving early and occupying lower-elevation sites closer to the coast, produced better-nourished chicks earlier in the season. However, they averaged half the number of chicks fledged, compared to breeders that arrived later in the season. Late breeders were forced by unavailability of optimal habitat to nest in more elevated areas, forming mixed colonies with cormorants, which, in turn, provided them with protection from nest predators. This study provides an example of the role of luck in nature, and how it may compensate for differences in individual fitness.

their risk of collision. However, differences in efficacy between types of devices, and in some cases conflicting results, place in question the ability of these devices to reduce collision risk to birds. Here, we investigated the efficacy of three types of flight diverters in reducing avian collision with power lines: yellow spiral, orange spiral, and flapper, additionally we used unmarked spans as a control. We recorded bird collisions and estimated removal rates of bird casualties by scavengers in three different 400 kV transmission lines comprising 133 spans in southern Spain. A total of 131 dead birds from 32 species were found. The power line and the type of marker significantly affected avian mortality. The flapper flight diverter was responsible for a 70.2% lower mean avian mortality rate (95% Confidence Interval: 50e90%), followed by the orange spiral (mean ¼ 43.7%, CI ¼ 15.8 e71.6%) and the yellow spiral (mean ¼ 40.4%, CI ¼ 2.8e78%), compared to control spans. Flappers were the only marker that showed greatest reduction in relation to non-marked spans. The flapper flight diverter showed the highest reduction in mortality and the narrowest confidence interval when tested in different environmental conditions, and thus may serve as a better alternative to the more commonly used spiral flight diverters

Historical variations (1966-2016) in the exposure to inorganic elements in raptors of South West Spain have been little studied. Therefore, uncertainty exists concerning whether environmental or anthropogenic inputs, as well as dietary strategy shift, may cause changes in exposure patterns. To address this gap, essential and non-essential inorganic elements were measured in Common kestrel (Falco tinnunculus) feathers from museum specimens and free-living individuals spanning a 50-year period. Moreover, stable isotopes of δ13C and δ15N were also measured as proxies of Common kestrel feeding ecology over time. In general, all elements showed significant increasing trends overtime, suggesting changes of inputs from local sources. Moreover, δ15N signatures were correlated to the variations in Al, Cr, Cu, Fe, K, Li, Mg, Mn, Ni, P, Pb, Rb, Sr, Ti, V and Zn concentrations, suggesting trophic changes in this kestrel population as well as possible biomagnification processes. Finally, some values of Cr, Mn and Pb were above the threshold concentrations of potential toxicity.

We investigated the distribution of juvenile dispersal distances of a territorial long-lived species with deferred maturity, the Spanish imperial eagle Aquila adalberti. Here we used a reintroduction program as an experimental approach to test predictions of different hypotheses about the distribution of juvenile dispersal distances: competition and wandering behavior. We determined maximal juvenile dispersal distances of 59 young eagles; 1) 30 wild non-manipulated individuals, and 2) 29 tranlocated young under an ad libitum feeding program, released with adults breeding in the area. The competitive displacement hypothesis predicts a leptokurtic distribution of distances in wild non-manipulated young as well as in released young. Under the ‘wandering’ hypothesis, however, a leptokurtic distribution is expected in wild young but a normal distribution would be expected in young released (with adults in the release area), owing to a general improvement in the nutritional status of released young that have been fed ad libitum, as is usual in reintroduction programs. Additionally, a negative relationship between hatching date and dispersal distances is expected in wild young but no relationship in released young under ad libitum feeding. Mean maximum dispersal distances for all the juvenile eagles was 142.8 km. No differences between sexes were found, nor between populations or between wild and reintroduced young. Wild young distances were not normally distributed, being closer to a Poisson distribution. In contrast, released young with adults (under ad libitum feeding) showed a normal distribution. Wild birds showed a significant negative relationship between dispersal distance and hatching date, with young that hatched late in the season dispersing shorter distances. However, released young under ad libitum feeding showed no significant relationship between hatching date and dispersal distance. These results support the ‘wandering’ hypothesis as the main driver of the distribution of dispersal distances., The reintroduction program was supported by GIASA, Fundación Santander, Fundación Migres and Junta de Andalucía.

Este artículo contiene 9 páginas, 3 figuras, 1 tabla., The depopulation of rural areas by humans (or rural exodus) in southern Europe, and the associated abandonment of cropland, had marked ecological consequences on wildlife, which became evident approximately fifteen years ago. Shrub and tree encroachment, and the expansion of forest birds and the formerly persecuted mammalian ungulates and carnivores, were highlighted as the major consequences of the rural exodus in Italy. In this report, we provide a more integrative view, and show that a rural exodus also explains other ecological phenomena that are usually treated independently. After reviewing the ecological consequences of the rural exodus that has been affecting a large part of Spain during the last six decades, we suggest that this set of ecological consequences also includes the movement of shy-selected predators and large, big game species out of their former ecological refuges, as well as increased frequencies of individuals with bolder-behaviours in recovering populations. We develop a tentative conceptual model linking the increasing approach of wildlife to anthropogenic habitats and human depopulation of rural areas. These links are created by the increasing difficulty to survive and reproduce in recovering, high-predation wild areas, due to mesopredator release and the loss of fear to humans, among other factors. We acknowledge that the recovery of formerly persecuted wildlife in depopulated landscapes has been helped by conservation policies, but we suggest that policies alone cannot explain the observed changes. Finally, we propose that the processes we analyse on a national scale could be taking place in Europe on a continental scale as well, and will most likely occur in the future in other regions of the world, with the current growth in economies., AMA received funding from Xunta de Galicia (Programa de Investigaci´on Competitiva del Sistema Universitario Gallego, ED431C 2018/57). XF thanks the financial support of Fundaci´o Barcelona Zoo and Ajuntament de Barcelona and MINUARTIA Estudis Ambientals.

Power lines are one of the mammals’ mortality factors. There are some records of electrocuted large mammals such as elephants and leopards in India, deer and cougars in the USA. In this paper, we r...

An increasing number of wildlife-vehicle collisions occur each year worldwide, which involves extensive economic costs and constitutes one of the main anthropogenic causes of animal mortality. Because of this, there is an urgent need to identify the factors leading to collision hotspots and thus implementing effective mitigation measures. By using a stratified random sampling survey, we investigated the fine-scale determinants of roadkill probability in small and medium-sized birds and mammals across a country-size region of Southern Spain, Andalusia (87,000 km), located within a global biodiversity hotspot. During two consecutive seasons, we regularly surveyed 45 road transects of 10 km each and characterized the site-specific attributes of both roadkill and random points, including traffic density, road design (embankments, medians, fences, roadside vegetation and distance to curves), and adjacent landscape matrix. Based on this information, we investigated variation in collision risk according to landscape and road features, and the life history of the affected taxa. Mortality rates of mammals and birds increased with traffic density, and were also significantly affected by the distance to the nearest curve, slope of embankments, height of roadside vegetation, and land use adjacent to roads. Road mortality of both birds and mammals was related to the presence and typology of fences and center medians, so more densely vegetated medians and smaller mesh sizes reduced roadkill probability. Overall, our results indicate that roadkill risk may vary at exceedingly small spatial scales. The information provided by this extensive survey may be used to identify taxa-specific factors associated to roadkill risk and priority points for action. Our findings will therefore be relevant for the design of safer roads for both drivers and wildlife through the application of effective mitigation measures.

The aim of this study was to estimate global population trends of abundance of two endemic migratory seabird species breeding in the Mediterranean Sea, Balearic and Scopoli's shearwaters, from migration counts at the Strait of Gibraltar. Specifically, we assessed how regional environmental conditions (i.e. sea surface temperature, chlorophyll a concentration, NAO index and fish catches), as proxies of climate change, prey availability and human-induced mortality factors, modulate the interannual variation in shearwater numbers. The change in the migratory population size of both shearwater species was estimated by fitting Generalized Additive Models (GAM) to the annual counts against the year of observation. Specifically, we modelled daily counts of migrant shearwaters during the post-breeding season. Contrary to current estimates at breeding colonies, coastal-land based counts of migrating birds provide evidence that Baleric and Scopoli's shearwaters have been recently increasing in the Mediterranean Sea. Our results highlight that demographic patterns in these species are complex and non-linear, suggesting that most of the increases have happened recently and intimately bounded to environmental factors, such as chlorophyll concentration and fisheries, that are closely related to human activities. Counts of migrating birds at strategic coastal points may provide useful estimates of the global population trend, as well as an efficient and rapid assessment of these and other seabird species in the Mediterranean. Keywords: Chlorophyll, Climate change, Fisheries, Seabird, Monitoring

1. Supplementary feeding is a common practice to raise reproductive output in raptors and other species; nevertheless, its application in conservation has only recently been discussed critically. Here, we analyse the effect of supplementary feeding in territorial raptors, taking advantage of two long-term datasets for the Spanish imperial eagle (Aquila adalberti) and bearded vulture (Gypaetus barbatus). In both species, supplementary feeding was used over four years, allowing the extraction of eggs or nestlings for reintroduction programmes. 2. Both populations increased during the last 20 years. In 2001, only 10 Spanish imperial eagle pairs were found in Sierra Morena, increasing to 91 pairs in 2015 (810% of increase). The Bearded vulture population in Aragon increased from 15 occupied territories in 1988 to 67 in 2012 (347% of increase). Density-dependent breeding productivity on habitat heterogeneity was established in both populations. 3. Results of generalized linear mixed model analysis with relative productivity as the dependent variable, species and supplementary feeding as fixed factors, and territory as random factor showed a significant effect of supplementary feeding on relative productivity in both species as well as in the interaction between territory and supplementary feeding. This implied a different response among territories to supplementary feeding. Birds in poor-quality territories with low productivity levels responded more strongly to supplementary feeding than birds in territories with higher levels of natural productivity. 4. A reintroduction programme based on supplementary feeding and extraction of nestlings costs eight times less than the same programme based on captive breeding and takes 10 years less. 5. Synthesis and applications. Supplementary feeding in territorial raptors could be useful (1) in an episodic main prey collapse and (2) in poor-quality territories in a high-density population, to produce extra young for reintroduction programmes. For greatest efficiency, supplementary feeding needs to be targeted at poorer territories in which the reproductive rate has the potential to be raised by provision of extra food. The extra young produced can then be used in reintroduction programmes in which chances of recruiting to a breeding population are high.

Migration is a significant event in the annual cycle of many avian species. During migration birds face many challenges, including unfamiliar foraging and refuge habitats, resulting in a much higher rate of mortality during migration than during other seasons of the year. Weather may significantly affect a bird's decision to initiate migration, the course and pace of migration, and its survival during migration. Each of these influences may impact the counts of migrating birds at geographical convergence zones or bottlenecks. It is important to quantify the effect of short-term weather on these counts to appropriately interpret and use such counts in other analyses. To this end, we aim to assess the effects of local and regional weather conditions on the migration counts of soaring birds at the Strait of Gibraltar during post-breeding migration. We used information-theoretic approaches to analyse the influence of local weather and weather in northern Spain on the migration counts of five soaring bird species from two count sites near the Strait of Gibraltar. Migration counts were higher on days with local northerly and westerly winds, often following a day of easterly winds, on days with local high pressure systems, and often following a day of lower pressure. Weather conditions in northern Spain influenced migration counts at the Strait of Gibraltar, but the effects were much weaker than local weather conditions. We confirm that short-term weather conditions, locally and regionally, can influence migration counts and should thus be considered when these counts are used in other analyses., This study was funded by grants from the Regional Ministry for Environment of Andalusia and from Fundación Migres. We would like to thank the board of Fundación Migres for their continued support. We would like to thank Boise State University's Raptor Research Center for additional financial support to continue the collaborative development of this work.

Reintroductions have been increasingly used for species restoration and it seems that this conservation tool is going to be more used in the future. Consequently a better knowledge of consequences of this kind of management is needed. Several authors have found differences in dispersal distances among wild and reintroduced individuals; although no common explanation for this general trend ( i.e. released animals moving farther than wild ones) has been proposed. Here we compared the dates of dispersal and the distribution of maximum distances during juvenile dispersal between a natural high density population and an alternative situation where young Spanish imperial eagles ( Aquila adalberti ) were reintroduced in a new area with a very low intra-specific density, and ad libitum feeding until the onset of dispersal. Results showed that maximum dispersal distances were longer in translocated (mean = 205 km) than in control juvenile eagles (mean = 119.70 km), and the shape of the distribution changed from leptokurtic right-skewed to quasi-normal. According to our results, for reintroduced young fed ad libitum , we can predict that effective dispersal distances will be longer in reintroduced young during juvenile dispersal than in natural populations. But dispersal distances might also depend on the distance from the release area to the nearest breeding population of the species. For reintroductions close to other existing populations, immigration of released young into existing populations would be greater than expected.

We examined the relationships between different environmental factors and the alpha and beta-diversity of terrestrial vertebrates (birds, mammals, amphibians and reptiles) in a Mediterranean region at the landscape level. We investigated whether the mechanisms underlying alpha and beta-diversity patterns are influenced by energy availability, habitat heterogeneity and temporal variability and if the drivers of the diversity patterns differed between both components of diversity. We defined alpha-diversity as synonym of species richness whereas beta-diversity was measured as distinctiveness. We evaluated a total of 13 different predictors using generalized linear mixed model (GLMM) analysis. Habitat spatial heterogeneity increased alpha-diversity, but contrastingly, it did not significantly affect beta-diversity among sites. Disturbed landscapes may show higher habitat spatial variation and higher alpha-diversity due to the contribution of highly generalist species that are wide-distributed and do not differ in composition (beta-diversity) among different sites within the region. Contrastingly, higher beta-diversity levels were negatively related to more stable sites in terms of temporal environmental variation. This negative relationship between environmental stability and beta-diversity levels is explained in terms of species adaptation to the local environmental conditions. Our study highlights the importance of temporal environmental variability in maintaining beta-diversity patterns under highly variable environmental conditions.

The Osprey (Pandion haliaetus) is an emblematic example of conservation. Currently, the species is progressively recovering in population size and range after dramatic reductions as a consequence of human persecution and the use of pesticides in the nineteenth and twentieth centuries. Here, we analysed the population trend and productivity in relation to the nesting substrate (artificial structures or trees) and the protection status of the nest location (inside or outside protected areas) in the eastern German population of Ospreys. The Osprey population steadily grew during the study period (2000–2009), accompanied by the increased use of artificial structures for nesting, possibly due to the scarcity of suitable natural nest sites in the region. Pairs nesting in trees showed higher variance in productivity than those nesting on artificial supports during the study period. Further, the productivity recorded in Ospreys nesting on natural sites decreased during the study period, regardless of the protection status of the nest location, whereas it did not vary for pairs nesting on artificial structures. The productivity of Ospreys was also related to the protection status of the nest location since pairs breeding inside protected areas, either in natural or on artificial nest sites, showed higher productivity than pairs nesting outside protected areas. These findings suggest that the protection of the nest location and the type of substrate used for nesting are relevant factors underlying the breeding performance in this Osprey population and are therefore key to its management.

Many threatened species in Europe have been expanding their distributions during recent decades owing to protection measures that overcome historical human activity that has limited their distributions. Range expansion has come about via two processes, natural expansion from existing range and reintroductions to new ranges. Reintroductions may prove to be a better way to establish populations because individuals are less subject to competitive relationships lowering breeding success than individuals expanding from existing populations. Whether this is true, however, remains uncertain. We compared success of breeding pairs of an expanding and a reintroduced population of spanish imperial eagles monitored for over 15 years in the south of Spain. We found significant differences in productivity between breeding pairs of each population. Newly established territories in reintroduction areas were almost three times more productive than new territories established as individuals expanded out from an existing population. We conclude that among these eagle populations reintroduced to new areas may fare as well or better than individuals expanding out form existing populations.

1. Endangered species subjected to reintroduction programmes often occur as small and isolated populations with local high density and depressed fecundity. Variation in territory quality may lead to this low fecundity owing to increasing occupation of suboptimal territories as population density grows, known as the habitat heterogeneity hypothesis (HHH). In this context, food supplementation in poor territories may be used to produce extra young which could be allocated to reintroduction programmes. 2. We analyse the density-dependent fecundity pattern and the underlying mechanism in a small population of bearded vultures Gypaetus barbatus in Aragon (northeast Spain). We then use population simulations to examine the viability of a hypothetical reintroduction programme using extra young produced by supplementary feeding on poor-quality territories and the effect on the donor population. We also compare the economic cost of such a reintroduction programme in relation to the cost of a traditional captive breeding programme. 3. The wild population showed clear negative, density-dependent fecundity regulation driven by the HHH mechanism. Simulations showed that extractions for translocations had no relevant long-term effects on the donor population viability, but a marked population reduction during the extraction period. However, the implementation of supplementary feeding to produce extra young for translocation lessened significantly this expected initial population reduction. 4. Analyses showed that the annual budget of a captive breeding programme for this species could be seven times more expensive than the translocation of extra young produced by food supplementation. 5. Synthesis and applications. Reintroduction programmes based on translocation of wild-reared individuals, after a supplementary feeding programme oriented to poor-quality territories, provide a source of young at least seven times cheaper than those from captive breeding programmes. The use of this approach would decrease initial effects on donor population avoiding public criticism. Increasing the number of young released during the first years of the reintroduction decreases total financial cost and increases the final population size in the new area.

This study examines the responses to human presence of the most abundant shorebird species in an important coastal migration staging area (Los Lances Beach, southern Spain). Long-term census data were used to assess the relationship between bird abundances and human densities and to determine population trends. In addition, changes in individual bird behaviour in relation to human presence were evaluated by direct observation of a shorebird resident species. Our results show that a rapid increase in the recreational use of the study area in summer has dramatically reduced the number of shorebirds and gulls which occur, limiting the capacity of the site as a post-breeding stop-over area. In addition, the presence of people at the beach significantly reduced the time that resident species spent consuming prey. Negative effects of human presence on bird abundance remain constant over the study period, showing no habituation to human disturbance in any of the studied species. Moreover, although intense human disturbance at Los Lances Beach occurs mainly in summer, the human presence observed is sufficient to have a negative impact on the long-term trends of a resident shorebird species. The impacts of disturbance detected on shorebirds and gulls may be reversible through management actions that decrease human presence. We suggest a minimum distance of 80 m for any track or walkway from those areas where shorebirds are usually present, particularly during spring and summer, as well as an appropriate fencing in the most sensitive area.

Satellite tracking is an invaluable tool in the study of bird movements. However, the normally small sample size it involves makes it difficult to obtain data spanning the entire range of migratory behaviour found in particular populations. We recently reported that Spanish immature Short-toed Snake Eagles leave their winter quarters in sub-Saharan Africa to occupy summering areas in northern Africa (north of the Sahara), in contrast to previously reported behaviour of a young French eagle which remained during the summer in the sub-Saharan wintering range. A more recent increase in the sample size of tracked young snake eagles further extends our knowledge of the summering behaviour of this species with one immature reaching the European range but occupying four widely-separated areas during the course of the summer. In the short-term, technology progress may provide the normal use of representative samples to increase accuracy in movement ecology studies.

© 2014 Dipartimento di Biologia, Università di Firenze, Italia. Siblicide may be >facultative> or >obligate>. When food resources provided by the parents are insufficient to rear a whole litter successfully, dominants may kill their subordinate siblings, either directly by physical damage, or indirectly through enforced starvation. This phenomenon is termed >facultative siblicide> and occurs in a wide range of bird species and at least one mammalian species. In contrast, when the lowest ranking sibling is routinely killed by its dominant brood mate or littermate this is called >obligate siblicide>, and seems to affect in particular large, long-lived species characterized by intense competition for breeding sites. This >obligate siblicide> has intrigued researchers for decades, trying to find an evolutionarily satisfactory explanation for this extreme behaviour. We review all scientific literature concerning sibling aggression published in the last 66 years. A bibliography search resulted in 104 references during the last 66 years, where birds represented 88% of the total published papers. Eleven hypotheses have been formulated for explaining these results, finding that siblicide is a complicated behaviour not controlled only for parents or chicks or environmental changes, but for a whole range of factors. These hypotheses have been identified and discussed according to actual supporting data. The relationship between food resources and brood reduction was widely documented; a sustained increase in food availability led to a highly significant decrease in both frequency and intensity of aggressiveness of the older chick towards its younger sibling in facultative species, also finding similar results in obligate siblicidal species. These results would suggest siblicide is an adaptive behaviour. This review tends to show that there is probably more than a single cause behind this behaviour. We conclude that more aspects must be considered in the design of future studies in order to understand the potential evolutionary sense of aggressive behaviour among siblings, especially those concerning food allocation decisions by parents.

We study the effects of heat loss and nest site quality on fecundity in a chinstrap penguin (Pygoscelis antarctica) colony on Deception Island, Antarctica. During the austral summers of 1990-1991, 1993-1994, and 1995-1996, 441 randomly selected nests were analyzed. Penguins breeding in the center of subcolonies hatched significantly earlier and had larger broods and than those nesting near or at the edge of the subcolonies. These differences, however, were significantly affected by interaction between year and nest location, being highly significant in colder years, when peripheral nests produce fewer young. Analysis of the rate of heat loss showed that penguins breeding at the edge of subcolonies lost heat twice as rapidly as those breeding in the interior of the subcolony. In a re-occupation experiment, evacuated center nests were re-occupied almost ten times as rapidly as edge nests. An analysis of mean fecundity in the period 1991-1996 and mean wind chill suggested that most of the variability in fecundity among years was related to differences in the rate of heat loss. Subcolonies tend to be as circular as possible, thereby decreasing the proportion of edge nests as the size of subcolony increases. Our results support the site-dependent fecundity hypothesis. © 2014 Springer-Verlag Berlin Heidelberg.

The aim of this study was to assess the exposure and potential effects of the toxic elements released by the Aznalcollar spillage on the fecundity of the booted eagle (Hieraetus pennatus) population of Doñana National Park. We measured As, Cd, Cu, Pb, Zn, Sb and Tl levels in the blood of 24 individuals after the accident and also used data of reproductive performance of the species from 1976 to 2000. While As, Sb and Tl were below their detection limits and only 3 samples were above detection limit for Cd (0.02–0.04 μg/dl), mean levels of Cu, Zn and Pb (μg/dl) were found to be 38.736, 532.937 and 0.719, respectively, in fledglings; and 66.112, 652.571 and 1.825, respectively, in adults. These levels were higher in adults, but they did not differ significantly between age classes and were at safe levels. In addition, a positive relationship between relative fecundity and the combination of Cu, Zn and Pb was observed. Following the mining spill, the mean population fecundity was lower (0.536 fledglings per pair in the population) than before (1.093). However, the decrease in fecundity over time was also related to the increase of breeding pairs, suggesting a density-dependent regulation and nullifying the mining spillage effect. Thus, although raptors have proved to be highly valuable biomonitors of environmental pollution, we must be especially cautious and go beyond the apparent effects that sometimes we quickly believe to detect, leading us to reach mistaken conclusions that could affect our management plans., This work was supported by funding from Fundación Migres through a collaboration project with Cobre Las Cruces, S.A. (CLC). Field work was included in the wildlife monitoring project (16/98, CSIC). Thanks to the author of the booted eagle picture of the graphical abstract (Artemy Voikhansky/CC-BY-SA-3.0). The picture of the accident of the graphical abstract is from the report “Ciencia y Restauración del Río Guadiamar” published by “Consejería de Medio Ambiente de la Junta de Andalucía”.

[Capsule] In Black-browed Albatrosses Thalassarche melanophris nutritional condition is correlated between parents and their offspring., [Aims] To test resource allocation hypotheses analysing the relationship between parental and offspring nutritional condition., [Methods] We measured blood chemistry parameters related with nutritional condition in 24 parents and their nestlings in a colony of Black-browed Albatrosses., [Results] There were no significant differences in blood parameters between sexes or location of the nest within the colony, neither among adults nor among nestlings. We found a significant positive correlation between parents and the nutritional condition of their offspring, measured as urea, uric acid and beta-hydroxybutyrate concentrations in blood., [Discussion] These relationships demonstrate that condition of the young seems to be merely a reflection of parental condition. An interesting relationship between alkaline phosphatase concentration in adults and nutritional condition of their nestlings was found, suggesting that age of the parents would be a key factor explaining quality of the nestling., Fundacion Migres supported the present study.

Blood chemical reference values and variations in them in long-lived endangered birds are of metabolic, veterinary, ecological and/or taxonomic interest. In the present study, we for the first time provide such reference values and test the influence of sex, age, and nest location on up to 11 plasma values in nesting black-browed albatrosses (Thalassarche melanophrys) that we sampled in 2015 on the Falkland Islands. Our results showed that differences between sexes were not significant for any of the parameters for which we tested. We found insignificant differences in metabolically related parameters in nestlings being raised in the middle of nesting colonies and those being raised at the edges of the colonies indicating that nest location did not affect the nutritional status or health of young, developing albatrosses. Conversely, age had a significant effect on a number of metabolites, inorganic ions and enzymatic activity. In particular, age-related differences in glucose, triglyceride, urea, and uric acid suggested that the relative metabolic rate was higher in nestling than in adult albatrosses., Fundacion Migres supported the present study.

Migration monitoring may allow us to detect population trends over large geographic areas because the pattern of change in migrant counts may be expected to follow the pattern of change in population size. We analysed recent regional European population trends of migratory soaring birds from rates of change in migration counts over the Strait of Gibraltar (Spain) during the years (1999–2013). An additional bottleneck (Organbidexka, France) within the same migratory route and period was also considered. We estimated count trends by fitting a log-generalized linear model to the time series of each species counts. The counts in Organbidexka were used to test the consistency in the observed trends over the Strait of Gibraltar. Migration counts of White and Black Storks, Black Kites, Short-toed and Booted Eagles as well as Egyptian Vultures showed a linear increase over the Strait of Gibraltar throughout the 15-year period. In contrast, Honey Buzzard numbers remained stable. Trends were highly consistent with those recorded in Organbidexka. We suggest that the larger slopes for the trends in Organbidexka when compared with the Strait reflect an increasing tendency in these species to overwinter in southern Europe. A combination of complementary data sets collected at different bottleneck sites within the European–African flyway system may become a fundamental tool for the investigation of migratory patterns and population trends and changes of soaring migrant birds all over Europe.https://doi.org/10.1007/s10531-016-1047-4, The data counts from the Strait of Gibraltar analyzed in the study were collected in field monitoring campaigns 1999/2012 funded by grants of the Consejeria de Medio Ambiente of the Junta de Andalucía (Spain)

Wind is increasingly being used as a renewable energy source around the world. Avian mortality is one of the negative impacts of wind energy and a new technique that reduces avian collision rates is necessary. Using the most frequently-killed species, the griffon vulture (Gyps fulvus), we studied its mortality at 13 wind farms in Tarifa, Cadiz, Spain, before (2006-2007) and after (2008-2009) when selective turbine stopping programs were implemented as a mitigation measure. Ten wind farms (total of 244 turbines) were selectively stopped and three wind farms (total of 52 turbines) were not. We found 221 dead griffon vultures during the entire study and the mortality rate was statistically different per turbine and year among wind farms. During 2006-2007, 135 griffon vultures were found dead and the spatial distribution of mortality was not uniformly distributed among turbines, with very few turbines showing the highest mortality rates. The 10 most dangerous turbines were distributed among six different wind farms. Most of the mortalities were concentrated in October and November matching the migratory period. During 2008-2009, we used a selective stopping program to stop turbines when vultures were observed near them and the griffon vulture mortality rate was reduced by 50% with a consequent reduction in total energy production of by the wind farms by only 0.07% per year. Our results indicate that the use of selective stopping techniques at turbines with the highest mortality rates can help to mitigate the impacts of wind farms on birds with a minimal affect on energy production. © 2011 Elsevier Ltd.

Summary 1. Wind farms generate little or no pollution. However, one of their main adverse impacts is bird mortality through collisions with turbine rotors. 2. Environmental impact assessment (EIA) studies have been based on observations of birds before the construction of wind farms. We analysed data from 53 EIAs in relation to the actual recorded bird mortalities at 20 fully installed wind farms to determine whether this method is accurate in predicting the risk of new wind farm installations. 3. Bird data from EIAs were compared with bird collisions per turbine and year at functional postconstructed wind farms to identify any relationship between pre- and post-construction studies. 4. Significant differences in birds recorded flying among the 53 proposed wind farms were found by the EIAs. Similar results were obtained when only griffon vultures Gyps fulvus and other raptors were considered. There were significant differences in indexes, including the relative index of breeding birds close to proposed locations, among the 53 proposed wind farm sites. 5. The collision rate of birds with turbines was one of the highest ever recorded for raptors, and the griffon vulture was the most frequently killed species. Bird mortality varied among the 20 constructed wind farms. 6. No relationship between variables predicting risk from EIAs and actual recorded mortality was found. A weak relationship was found between griffon vulture and kestrel Falco sp. mortality and the numbers of these two species crossing the area. 7. Synthesis and applications. There was no clear relationship between predicted risk and the actual recorded bird mortality at wind farms. Risk assessment studies incorrectly assumed a linear relationship between frequency of observed birds and fatalities. Nevertheless, it is known that bird mortality in wind farms is related to physical characteristics around individual wind turbines. However, EIAs are usually conducted at the scale of the entire wind farm. The correlation between predicted mortality and actual mortality must be improved in future risk assessment studies by changing the scale of these studies to focus on the locations of proposed individual wind turbine sites and working on a species specific level.

Over the past 40 years, the study of animal populations has shifted from a relatively simple science that assumed the most crucial regulating mechanisms were the intrinsic properties of breeders, to a more complex and refined discipline that reflects a greater understanding of populations and their dynamics. Part of this shift has been the explicit recognition of the importance of a previously overlooked nonbreeding component of animal populations, the so-called floaters. Here we review and discuss the various effects that pools of floaters can have on the structure, dynamics and persistence of bird populations. Under some circumstances floaters can be both active intruders that can alter the breeding performance and behavioural traits of territory owners, as well as secretive presences reducing the extinction risk of populations. Floaters are crucial elements in conservation biology, and knowledge of their behaviour and dynamics in avian communities can be a key factor in the success of conservation strategies. Firstly, larger pools of floaters are associated with more stable breeding populations, even in cases where breeding output could be impacted through interference by floaters. Secondly, the effects of habitat loss and mortality rates are frequently ignored in areas where floaters settle, and consequently conservation measures tend to overlook these sites, potentially leading to increased risks of mortality among floaters. Thirdly, because an increase in the proportion of juveniles in the breeding component of a population may be because of increased pre-adult and/or adult mortality rates, a change in the age of breeders has the potential to function as a warning of an imminent decline in breeding populations. Most population studies have only considered the breeding components of animal populations, so it is time now to focus attention on the floater component, wherein the solution to many conservation issues may be found.

We tested some predictions of parental investment theory by studying the aggressive behaviour of colonial nesting chinstrap penguins (Pygoscelis antarctica) against human intruders into their nesting territories. We tested for differences in the aggressive behaviour of penguins according to offspring age (eggs vs. chicks), offspring number, nest location in the colonies (central vs. peripheral) and sex. Offspring age was the main factor influencing nest defence, although nest location and sex were also important. Chicks were defended more strongly than eggs, in accordance with changes in the reproductive value of offspring, and this increase in aggressiveness was not related to revisitation of the same individuals. The level of aggression of penguins breeding in central sites was higher than that of peripheral birds, a difference that could be due to the lower residual reproductive value of central-nesting, probably older, birds. The stronger aggressiveness of males could be due to a combination of factors related to sexual selection and life-history traits. Offspring number did not affect the level of nest defence.

The Coscoroba Swan (Coscoroba coscoroba) is an unusual member of the Anatidae found in South America, from the Falkland Islands and Tierra del Fuego through Chile and Argentina, Uruguay, and Paraguay as far north as Mato Grosso do Sul in Brazil. The species is not threatened globally, but some local populations have declined and the status of others is unknown. The objective of this study was to quantify the plasma chemistry of a wild population of Coscoroba Swans in southern Brazil during their molting period. We captured 12 chicks, 14 juveniles, and 31 mature birds. The following blood parameters were measured: glucose, cholesterol, triglycerides, HDL cholesterol, uric acid, creatin-kinase, aspartate amino transferase, alanine-aminotransferase, alkaline phosphatase, amylase, and pancreatic amylase. Significant differences between males and females were not observed for any of the parameters, and only the levels of alkaline phosphatase differed significantly among age groups. © Wildlife Disease Association 2010.

Markov chains have been frequently used in community ecology to model successional changes, but little attention has been paid to its application in population ecology as a tool to explore the outcomes of species interactions. Markov models can be regarded as >null models> that provide predicted values under a no-change scenario against which the consequences of changes in variables of interest can be assessed. Here we explore Markov chains' potential to project population trends of competing species and derive sensible management strategies. To do that we use six years of field data on territory occupancy and turn-over of two competing top predators in a Mediterranean landscape: the golden and Bonelli's eagles. The results suggest that long-term coexistence of both species in the study area is likely, with the main limitation for their coexistence being the difficulties Bonelli's eagles have in colonising new territories that become available. To avoid future declines in the population of Bonelli's eagle, it is important to take into account that the positive effects of conservation strategies focused on encouraging colonization (e.g. decreasing disperser mortality) are likely to be larger than those focused on avoiding territory abandonment (e.g. decreasing adult mortality). Markov chains are likely to be useful to evaluate the relative merit of alternative management options in other territorial species when patterns of territory occupancy are the only reliable data available, as often happens with large predators. © 2008 Springer Science+Business Media B.V.

Brood reduction, the death of one or more chicks through siblicide or starvation, can occur through density-dependence in fecundity. Brood reduction may arise in territorial breeding systems either as a response to a high level of territorial interference in a situation of high density or as a result of habitat heterogeneity. To test the predictions of the two main hypotheses that attempt to explain how density-dependent fecundity is generated, the Habitat Heterogeneity Hypothesis (HHH) and the Individual Adjustment Hypothesis (IAH), we analysed the relationship between density and fecundity in an expanding population of Booted Eagles in Donana National Park, Spain, using an 18-year data series. We also studied the occurrence and frequency of brood reduction in the same Booted Eagle population to appreciate further its effects and the factors that influence its occurrence and frequency. Our results support the HHH in the present situation of high density, as fecundity in the better territories (older and more frequently occupied) was higher than in low quality territories and was not affected by population density in high density periods. Nevertheless, the fecundity of high quality territories was affected (although not significantly) by population density in periods of low density, suggesting that the IAH was supported when only high quality territories were occupied. Older territories were used more frequently and chicks in these areas hatched earlier and suffered lower mortality than in new territories. We found a significant negative relationship between mean fecundity and its skewness, a finding that also supports HHH. During years of food shortage, less frequently occupied territories suffered higher rates of brood reduction. Brood reduction in this Booted Eagle population was a consequence of the heterogeneous structure of the habitat, with some territories having a higher probability of brood reduction than others. Parental nutritional condition did not affect brood reduction. The effect of brood reduction on nestling quality and population dynamics is also discussed.

4 pages., he aim of this comment is to review the ecological issues concerning the role of individual and habitat heterogeneity as possible mechanisms explaining density-dependent fecundity in animal populations. Our intention is to discuss different approaches to determine whether or not studied populations are subjected to density-dependent processes and which mechanisms are involved. We show that because individual quality (e.g. measured in terms of age of breeding individuals) and territory quality can be correlated, untangling both effects on fecundity is frequently a difficult task. We discuss the misuse of statistical methods and other problems related to the specific characteristics of the studied populations that can have a strong influence on the conclusions reached by researchers working in this field., Thank you very much to K. Schmidt for their valuable suggestions that helped improving this manuscript throughout the reviewing process and also thanks to L. Svensson for editorial assistance. JB was supported by the Spanish Ministry of Education and Science through the post-doctoral program ‘‘Juan de la Cierva’’.

The dispersal behaviour of 30 radio-tagged young Spanish Imperial Eagles Aquila adalberti was studied in southwestern Spain in 1986–1990. The dispersal process involved first departure from the natal population, exploratory movements, temporary settlements and returns to the natal population. The dispersal process lasted for the whole of the immature period studied, and behaviour was radically different from that displayed by territorial adults. Movements between temporary settling areas and the natal population occurred continually throughout the dispersal period. Return to the natal population could be used by the young to explore the possibilities for pair formation where a vacancy may have occurred in the breeding population.