Summary. Birds of prey have been, in comparison to other avian groups, an uncommon study model, mainly due to the limitations imposed by their conservative life strategy (low population density and turnover). Nonetheless, they have attracted a strong interest from the point of view of conservation biology because many populations have been close to extinction and because of their recognised role in ecosystems as top predators and scavengers and as flagship species. Today, after more than a century of persecution, and with the exception of some vultures still very much affected by illegal poisoning, many populations of birds of prey have experienced significant recoveries in many regions of Spain and the European Mediterranean. These changes pose new challenges when addressing the conservation of raptors in the coming decades. On this basis, and from a preferentially Mediterranean perspective, we have focused our attention on the need of describing and quantifying the role of these birds as providers of bo... Resumen. Las aves de presa han sido, en comparación con otros grupos de aves, más raramente utilizadas como sujeto de estudios en ecología en razón de las limitaciones que impone su estrategia de vida (baja densidad de población, alta longevidad y baja natalidad). Por el contrario, han suscitado un gran interés desde el punto de vista de la biología de la conservación, debido a que sus poblaciones en muchos casos se han aproximado a la extinción, así como al reconocimiento de su papel en los ecosistemas como superpredadores y carroñeros como especies bandera. Hoy en día, tras más de un siglo de persecución, y con la excepción de algunos buitres todavía muy afectados por envenenamientos ilegales, muchas especies de aves de presa han experimentado importantes crecimientos poblacionales en muchas regiones de España y del Mediterráneo europeo. Este escenario plantea nuevos desafíos para abordar la conservación de las rapaces en las próximas décadas. Sobre esta base hemos focalizado nuestra atención en la nece...
Moult is one of three major events in the annual cycle of birds. However, in contrast to breeding and migration, relatively few studies have been carried out on this topic. This is particularly the case with the large group of birds of prey and is partly a consequence of a general lack of appreciation of the relevance of moult within the life cycle of species. This factor is exacerbated by the difficulty in obtaining large enough sample sizes in this group, since some species are scarce and birds of prey are almost always difficult to trap. Nevertheless, moult is an energy-demanding process that takes longer than the breeding cycle and, contrary to the latter, it occurs every year. We stress the importance of the annual moult process for providing a “fixed image” of an individual's biology and underline its utility in furthering knowledge of the life history of each species. In this review we first outline the basic definitions necessary for understanding the moult process, and discuss current information on the moult sequence of European birds of prey, as part of a comprehensive review of the mechanisms of the moult in each group. Secondly, we summarise the main methods used to study, analyse and understand the moult, and indicate how to use these to obtain relevant information. Thirdly, we explain the importance of the moult in the life cycle of birds of prey, and how we can use this information to advance our understanding of the ecology of each species. Finally, we include a view of possible strategies that may be used to improve future research, thanks to advances in knowledge of the moult process. —Zuberogoitia, I., Zabala, J. & Martínez, J.E. (2018). Moult in birds of prey: a review of current knowledge and future challenges for research. Ardeola, 65: 183–207.
Evolution by natural selection depends on the relationship between individual traits and fitness. Variation in individual fitness can result from habitat (territory) quality and individual variation. Individual quality and specialization can have a deep impact on fitness, yet in most studies on territorial species the quality of territory and individuals are confused. We aimed to determine if variation in breeding success is better explained by territories, individual quality or a combination of both. We analysed the number of fledglings and the breeding quality index (the difference between the number of fledglings of an individual/breeding pair and the average number of fledglings of the monitored territories in the same year) as part of a long term (16 years) peregrine falcon (Falco peregrinus) monitoring program with identification of individuals. Using individual and territory identities as correlates of quality, we built Generalised Linear Models with Mixed effects, in which random factors depicted different hypotheses for sources of variation (territory/individual quality) in the reproductive success of unique breeding pairs, males and females, and assessed their performance. Most evidence supported the hypothesis that variation in breeding success is explained by individual identity, particularly male identity, rather than territory. There is also some evidence for inter year variations in the breeding success of females and a territory effect in the case of males. We argue that, in territorial species, individual quality is a major source of variation in breeding success, often masked by territory. Future ecological and conservation studies on habitat use should consider and include the effect of individuals, in order to avoid misleading results.