Large Birds of Prey, Policies That Alter Food Availability and Air Traffic: a Risky Mix for Human Safety

Raptors are considered to pose one of the greatest aviation bird strike risk. We investigated raptor bird strikes reported at the largest Spanish airport (Adolfo Suárez Madrid Barajas; AS-MB) from 2009 to 2016 to determine the factors contributing to the increased incidences and develop recommendations to mitigate the risks. We hypothesized that increased raptor bird strikes resulted from changes in foraging and dispersal patterns of Iberian Peninsula vultures (Aegypius spp. and Gyps spp.) after 2004-2005. We used information on raptor bird strikes obtained from official databases and published studies, reported incidences of raptor bird strikes and their characteristics (i.e., time, location, species involved), data collected about raptor flight heights, and estimates of relative abundance of large raptors and their prey species obtained through standardized surveys conducted in the high priority aviation area around the airport to assess bird strike risks. Our field work was conducted from June 2014 to May 2016. We confirmed a direct relationship between the relative abundance of the raptors studied and their prey species in the priority aviation areas. Raptor bird strike risks increased during spring and summer when food sources were abundant in locations where flight altitudes of aircraft werenew, scarcer, and more distant food sources, enhancing the likelihood of overlap with air traffic corridors. Although further studies on aviation risk are needed, our results suggest the need implement immediate remedial management actions to alter vulture habitat quality by reducing food sources in sensitive areas, and providing alternative food resources at distances sufficiently far from commercial airports

Is it necessary managing carnivores to reverse the decline of endangered prey species? Insights from a removal experiment of mesocarnivores to benefit demographic parameters of the pyrenean capercaillie

This is an open access article distributed under the terms of the Creative Commons Attribution License.-- et al.Mesopredator control has long been used to alleviate the effect of elevated predation pressure on vulnerable, threatened or valuable species. However, the convenience of using mesopredator controls is technically questionable and scientifically-sound research is therefore required to evaluate the impact of predation on prey case by case. In this study we evaluated the effect of the alteration of terrestrial mesopredator dynamics on the demographic parameters of a relict capercaillie Tetrao urogallus aquitanicus population currently in decline for which the impact of predation has not previously been assessed. We used a six-year mesocarnivore removal experiment (2008-2013) together with seven-years of previous demographic information on capercaillies (1999-2007) within a before-after controlimpact (BACI) design to evaluate the effect of mesocarnivore removal on capercaillie demographic parameters and on spatial behaviour of the most frequent predatory mesocarnivores of the capercaillie (Martes spp. and red fox Vulpes vulpes). Using a dynamic siteoccupancy approach, the reduction of mesocarnivore population levels as a result of removal was clear for marten species, mainly during key months for capercaillie reproduction, but not for the red fox. Our results show that the breeding success of capercaillies was enhanced in areas where carnivores were removed and was inversely related to the occupation level of the studied mesocarnivores, although being only significant for Martes spp. Moreover, capercaillie predation rates were lower and adult survival seemingly higher in treatment during the removal phase. Cost-effective, long-term management interventions to ensure the recovery of this threatened capercaillie population are discussed in the light of the results. At our study area, the decision for implementing predation management should be included within a broader long-term conservation perspective. In this regard, a more feasible and sustainable management intervention in ecological and economic terms may be to balance the impact of mesocarnivores on capercaillies through the recovery of apex predators.The present work was commissioned by the Spanish Ministry of Environment, and the GALLIPYR-POCTEFA 2007 cofunded by the Generalitat de Catalunya and the European Union, who provided support in the form of salaries for authors [RM-O, IA, JP, JM-I], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. JVLB received a postdoctoral grant “Juan de la Cierva” from the Spanish Ministry of Economy and Competitiveness.”Peer Reviewe

Larger size and older age confer competitive advantage: dominance hierarchy within European vulture guild hierarchy within European vulture guild

Competition for limiting natural resources generates complex networks of relationships between individuals, both at the intra- and interspecifc levels, establishing hierarchical scenarios among diferent population groups. Within obligate scavengers, and especially in vultures, the coevolutionary mechanisms operating during carrion exploitation are highly specialized and determined in part by agonistic behavior resulting in intra-guild hierarchies. This paper revisits the behavioral and hierarchical organization within the guild of European vultures, on the basis of their agonistic activities during carrion exploitation. We used a dataset distilled from high-quality videorecordings of competitive interactions among the four European vulture species during feeding events. We found a despotic dominance gradient from the larger species to smaller ones, and from the adults to subadults and juveniles, following an age and body size-based linear pattern. The four studied species, and to some extent age classes, show despotic dominance and organization of their guild exerting diferential selection to diferent parts of the carrion. The abundance of these parts could ultimately condition the level of agonistic interactions. We discuss the behavioral organization and the relationship of hierarchies according to the feeding behavior and prey selection, by comparing with other scavenger guilds

Reconciling the conservation of endangered species with economically important anthropogenic activities: interactions between cork exploitation and the cinereous vulture in Spain

Limitation of disturbing activities around the breeding areas of protected species is not always possible, if these activities are economically important and have, in addition, positive effects on protecting the habitats of those protected species. Searching for optimal solutions making commercial exploitation of natural resources compatible with biodiversity conservation is thus of concern to managers and policy makers. This is the case of the cinereous vulture Aegypius monachus, breeding primarily in cork-oak woodland, and cork exploitation, a traditional socio-economic activity carried out in several Mediterranean countries, and critical for the maintenance of this important habitat. We studied the effects of this anthropogenic activity on the behaviour and breeding success of breeding cinereous vultures in Spain. For the adults, the probability of nest abandonment was dependent on the distance of workers from the nest and the level of noise; activities within 500m from the nest were likely to cause abandonment of the nest by adults, if the level of noise was intermediate or loud. Neither the size of the working group nor the use of machines per se, had any effect on the probability of nest abandonment. Pairs in an area of the colony exposed to intrusive anthropogenic activity had 20% lower breeding success than those in the same colony that were not exposed to these disturbances. If the application of buffer zones of 500m is not possible (as is likely given the economic losses involved), several alternatives are recommended based on our results to minimize the impact of these activities, in particular to diminish the noise level of cork extraction activities. Observational studies like this help understanding the magnitude of the problem and finding alternative solutions for harmonizing conservation and economic development.This study was carried out within the framework of the monitoring programme of the LIFE 03/NAT/E/0050 project ‘Conservation of the Spanish imperial eagle, cinereous vulture and black stork’, implemented by the Fundacion CBD-Habitat in conjunction with the autonomous communities of Castilla-La Mancha, Extremadura and Madrid and the Ministerio de Medio Ambiente, Medio Rural y Marino.Peer Reviewe

Conservation of the Cinereous Vulture Aegypius monachus in Spain (1966-2011): a bibliometric review of threats, research and adaptive management

Detecting and quantifying threats and researching and implementing management actions are key to improving the conservation status of endangered species. Bibliometric analysis can constitute a useful tool for the evaluation of such questions from a long-term perspective. Taking as a case study the Cinereous Vulture Aegypius monachus in Spain, we tested relationships between population dynamics, research efforts, existing threats and conservation milestones. The population growth of the species (from 206 pairs in 1976 to 2,068 in 2011) was parallelled by the increase in the total number of publications, the number of articles in SCI journals and the number of published works dealing with aspects of conservation, threats and management. These results are discussed in terms of cause-effect relationships taking into account that the influence of other non-mutually exclusive factors could also probably explain such associations. Similarly, we analysed the trend of the Cinereous Vulture breeding population with respect to different threats and indices of food availability, obtaining a positive correlation with the increase in big-game hunting bags in Spain. With respect to conservation milestones, we concluded that the current situation is positive in terms of the protection of the species and its habitat, with the situation in relation to food availability being unclear. Finally, we reviewed the main conservation actions that have been taken for the species in Spain and how these have been progressively modified based on new scientific and technical evidence, as an example of adaptive management applied to conservatio

Fumarel Cariblanco, Chlidonias hibrida

Peer Reviewe

La cigüeña negra, Ciconia nigra, en concentraciones postnupciales y migratorias ibéricas : fenología, actividad y estructura de edades

Las concentraciones migratorias y postnupciales de cigüeña negra han sido objeto de estudio en 22 localidades de las provincias de Ciudad Real, Cáceres y Badajoz (centro y oeste de España). Entre 2003 y 2006 se visitaron periódicamente distintos tipos de humedales con presencia habitual de la especie durante los pasos migratorios, desde el 21 de julio hasta el 10 de octubre. En 174 de las 339 visitas realizadas se detectó la presencia de cigüeña negra. El número promedio registrado de ejemplares por bando resultó de 11,3 ejemplares. Las fechas en que se contabilizaron más individuos, tanto en valores absolutos como relativos, correspondieron al período del 11 al 20 de septiembre. La mayor parte de los ejemplares datados (69,1%) resultaron adultos (plumaje de más de 3 años de edad), seguidos por jóvenes del año (20,2%) e inmaduros-subadultos (10,6%, 2-3 años de edad). A lo largo de todo el período migratorio se mantuvo constante la proporción de edades, salvo en el mes de octubre, cuando se incrementó la presencia aves juveniles. Durante las horas centrales del día se registró el mayor número relativo de aves sedimentadas en los humedales estudiados. Entre las 13:00 h y las 16:00 h (GMT + 2h) se censó el 62,7% de las cigüeñas negras presentes. Alrededor de la mitad de los individuos (52,5%) emplearon las áreas de concentración estudiadas para descansar y sestear

Effect of Methodological and Ecological Approaches on Heterogeneity of Nest-Site Selection of a Long-Lived Vulture

The application of scientific-based conservation measures requires that sampling methodologies in studies modelling similar ecological aspects produce comparable results making easier their interpretation. We aimed to show how the choice of different methodological and ecological approaches can affect conclusions in nest-site selection studies along different Palearctic meta-populations of an indicator species. First, a multivariate analysis of the variables affecting nest-site selection in a breeding colony of cinereous vulture (Aegypius monachus) in central Spain was performed. Then, a meta-analysis was applied to establish how methodological and habitat-type factors determine differences and similarities in the results obtained by previous studies that have modelled the forest breeding habitat of the species. Our results revealed patterns in nesting-habitat modelling by the cinereous vulture throughout its whole range: steep and south-facing slopes, great cover of large trees and distance to human activities were generally selected. The ratio and situation of the studied plots (nests/random), the use of plots vs. polygons as sampling units and the number of years of data set determined the variability explained by the model. Moreover, a greater size of the breeding colony implied that ecological and geomorphological variables at landscape level were more influential. Additionally, human activities affected in greater proportion to colonies situated in Mediterranean forests. For the first time, a meta-analysis regarding the factors determining nest-site selection heterogeneity for a single species at broad scale was achieved. It is essential to homogenize and coordinate experimental design in modelling the selection of species' ecological requirements in order to avoid that differences in results among studies would be due to methodological heterogeneity. This would optimize best conservation and management practices for habitats and species in a global context

Scavenging patterns of generalist predators in forested areas: the potential implications of increase in carrion availability on a threatened capercaillie population

The increases in ungulate populations and hunting bags throughout Europe and North America have resulted in higher carcass numbers available for mesocarnivore species in temperate and boreal forests. The increase in food resources can sustain denser predator populations, potentially affecting prey species such as the threatened western capercaillie Tetrao urogallus. We investigated the ungulate population trends in recent decades and the carrion use by facultative scavengers in areas of the Pyrenees occupied by capercaillie to assess the potential effects on predation of nests and adult birds, and on its population trend. We found a significant increase in the number of ungulates harvested during the period of sharp capercaillie population decline. Carrion was provided experimentally in forested areas occupied by capercaillie showing that remains were mainly consumed by red fox Vulpes vulpes, followed by wild boar Sus scrofa and marten species (Martes sp.). Season (cold or warm) was the most important factor determining scavenging activity in most species. Main predators of capercaillie nests and adults were martens and red fox, with no predation by wild boar. Our data show that main predators of capercaillie are the same species that mainly consume carrion, especially in winter, and that plentiful carrion resources could maintain higher populations of these species, potentially increasing predation pressure on the capercaillie population. This study shows that managing carrion arising from hunting activity in areas of capercaillie distribution is a necessary management action to reduce the available carrion biomass and so reduce the impact of mesocarnivores on capercaillie conservation.We acknowledge the forestry rangers of Generalitat de Catalunya for field work. The comments of two anonymous reviewers improved the previous version. This work was funded by the Spanish Ministry of Science, Innovation and Universities (RTI2018-099609-B-C22) and the Spanish Ministry for the Ecological Transition and the Demographic Challenge

Evidence that vulture restaurants increase the local abundance of mammalian carnivores in South Africa

Vulture restaurants are used worldwide as a conservation tool to provide threatened vultures with a source of supplementary carrion free from anthropogenic contaminants such as poisons and veterinary drugs. While the impacts of supplementary feeding sites on ecosystem and scavenging community dynamics have been investigated in Europe, no information is currently available for southern Africa. This study presents evidence that providing supplementary carrion for vultures stimulated an increase in local abundance of two species of mammalian carnivores, the brown hyaena (Hyaena brunnea) and the black-backed jackal (Canis mesomelas). These findings require that the wider impacts of providing supplementary carrion for conserving threatened species are fully investigated