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Contribución del anillamiento al conocimiento y conservación de las aves en España: pasado, presente y futuro.
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This annual report from the Bird Ringing Station of the Fuente del Rey Pond presents the results obtained during 2023. The station, located in Dos Hermanas, Seville, is part of a long-term ornithological monitoring project initiated in 2019, with the primary goal of studying the evolution of the wetland bird community through scientific ringing. In 2023, 23 ringing sessions were conducted, resulting in the capture of a total of 1,226 birds from 38 different species, including 966 new ringings and 260 recaptures. This year is notable for the inclusion of data in national and international projects and the continued training of new scientific ringers. Additionally, notable cases were documented, such as recapturing a Phylloscopus collybita (Common Chiffchaff) with a Belgian ring and completing two consecutive migratory cycles in the lagoon. The data collected provides key information for conserving and understanding species dynamics in response to environmental changes.
El anillamiento es un método que aporta una interesante información sobre la biología de las aves y permite realizar investigaciones en las que se apoya la gestión y la conservación, no sólo ornitológica, sino del medio ambiente en general. Pero el método requiere la participación de numerosos científicos y aficionados que desarrollen el marcado de las aves y el trabajo de campo. Y, para conseguir que exista suficiente número de éstos y de aquéllos, es necesario, previamente, alimentar su curiosidad y despertar su interés por el medio ambiente, por los animales y, particularmente, por las aves, además de potenciar actitudes respetuosas con el entorno y fomentar la sensibilidad como valor. Las vocaciones científicas nacen en las etapas previas a la universidad y las Ciencias Naturales entrañan un atractivo incuestionable para muchos jóvenes. Pero su aprendizaje encuentra, en nuestro actual modelo, un conjunto de dificultades ligadas a los cambios sociales. Especialmente complejo, resulta el proceso de enseñanza y aprendizaje en la etapa correspondiente a la adolescencia, en la que, a los cambios físicos del individuo, se unen las modificaciones de conducta que se traducen en la necesidad de reivindicarse frente a los adultos y en una natural rebeldía.
El anillamiento puede ser una buena herramienta para despertar el interés de los adolescentes por la naturaleza y sus efectos sobre los alumnos son lo suficientemente gratificantes como para superar las dificultades de su aplicación en las programaciones de los centros y poner en marcha su aplicación. Con esta
actividad se consigue que los alumnos muestren una mayor motivación ante el estudio de las Ciencias y ante el trabajo de campo; permite su acercamiento a la naturaleza y los hace más sensibles ante los problemas ambientales; potencia el compromiso en la conservación de la naturaleza; justifica la necesidad de trabajar con rigor y de forma metódica; fomenta la solidaridad y el aprecio por el trabajo en grupo, y facilita el reconocimiento del trabajo de los demás, algo muy necesario (y, lamentablemente, menos habitual de lo deseable) en cualquier actividad humana, incluida la investigación.
Natural sounds, and bird song in particular, play a key role in building and maintaining our connection with nature, but widespread declines in bird populations mean that the acoustic properties of natural soundscapes may be changing. Using data-driven reconstructions of soundscapes in lieu of historical recordings, here we quantify changes in soundscape characteristics at more than 200,000 sites across North America and Europe. We integrate citizen science bird monitoring data with recordings of individual species to reveal a pervasive loss of acoustic diversity and intensity of soundscapes across both continents over the past 25 years, driven by changes in species richness and abundance. These results suggest that one of the fundamental pathways through which humans engage with nature is in chronic decline, with potentially widespread implications for human health and well-being.
Carotenoid staining has been repeatedly shown to serve as a sexually selected individual quality signal. In different species, individuals that show brighter carotenoid-based signals have been found to have superior feeding abilities, recover faster from disease, and generally enjoy better body condition. In the common crossbill (Loxia curvirostra), the colour has also been related to the different populations, with northern and central European populations being described as redder than those in the Mediterranean region. A study in the Pyrenees showed that long-winged individuals had lower apparent survival, and the proportion of red individuals was higher in long-winged birds, concluding that they could be nomadic birds (that travel long distances). A priori, if the red crossbills are more mobile than the yellow and orange ones, their apparent survival will be lower. However, in our study, red males showed a greater survival than males of other colours and almost double than that of the yellow ones. These results suggest that red coloration is linked to higher quality individuals regardless of their mobility.
El incremento del solapamiento entre la muda y la reproducción en el carbonero común está ligado a un aumento en la frecuencia de segundas puestas: ¿Un posible efecto del calentamiento global?
El ascenso de las temperaturas debido al cambio climático está relacionado con un aumento de la duración de la temporada reproductiva de muchas especies de aves. Esto permite que más parejas intenten poner dos puestas durante la temporada reproductiva y conlleva que terminen sus actividades reproductivas más tarde; por tanto, estas actividades se podrían solapar con la muda postnupcial. Hemos comprobado si esto ocurre en dos poblaciones de carbonero común (Parus major) de España. La proporción de parejas con segundas puestas se ha incrementado del 1 % al 32 % durante el periodo de estudio en una de las poblaciones (Sagunto, 1995–2019), mientras que en la otra no ha cambiado (Quintos, 2006–2019; media 5 %). No hemos encontrado ninguna tendencia temporal en cuanto a la fecha de inicio de muda de los individuos que están criando en fechas tardías en ninguna de las dos poblaciones. La proporción de individuos de ambos sexos cuya muda y actividad reproductiva se solaparon se ha incrementado en Sagunto. En esta última población, el sexo y la edad, pero no el tipo de puesta, contribuyeron a explicar la variabilidad en la probabilidad de solapamiento entre los reproductores tardíos, ya que esta es mayor en los machos de primer año y menor en hembras adultas.
Stochasticity in food availability influences vital rates such as survival and fertility. Life-history theory predicts that in long-lived organisms, survival should be buffered against environmental stochasticity showing little temporal variability. Furthermore , to optimize survival prospects, many animal species perform migrations to wintering areas where food availability is larger. Species with large latitudinal distribution ranges may show populations that migrate and others that are resident, and they may co-occur in winter. One example of these species is the predatory raptor buzzard Buteo buteo. Here, we test whether temporal variability in the density of five small mammal species of prey inhabiting different habitats (shrubland and forests) influences local annual survival of buzzards in a wintering area depending on their age and residency status (resi-dents versus wintering individuals). We found that prey density explained a considerable amount of annual changes in local survival, which was higher for older and resident birds. This difference in local survival likely corresponded to philopatry to the wintering area, which was larger for residents and increased when prey density was larger. The total density of prey inhabiting open shrublands was the variable explaining more variance in temporal variability of local survival, even though the study area is mostly occupied by woodlands. Temporal population dynamics of the different small mammals inhabiting shrublands were not synchronous, which suggests that buzzards preyed opportunistically on the most abundant prey each winter. Generalist predation may buffer the impact of resource unpredictability for pulsed and asynchronous prey dynamics, typical of small mammals in winter.
Oceanic archipelagos are excellent systems for studying speciation, yet inference of evolutionary process requires that the colonization history of island organisms be known with accuracy. Here, we used phylogenomics and patterns of genetic diversity to infer the sequence and timing of colonization of Macaronesia by mainland common chaffinches (Fringilla coelebs), and assessed whether colonization of the different archipelagos has resulted in a species-level radiation. To reconstruct the evolutionary history of the complex we generated a molecular phylogeny based on genome-wide SNP loci obtained from genotyping-by-sequencing, we ran ancestral range biogeographic analyses, and assessed fine-scale genetic structure between and within archipelagos using admixture analysis. To test for a species-level radiation, we applied a probabilistic tree-based species delimitation method (mPTP) and an integrative taxonomy approach including phenotypic differences. Results revealed a circuitous colonization pathway in Macaronesia, from the mainland to the Azores, followed by Madeira, and finally the Canary Islands. The Azores showed surprisingly high genetic diversity, similar to that found on the mainland, and the other archipelagos showed the expected sequential loss of genetic diversity. Species delimitation methods supported the existence of several species within the complex. We conclude that the common chaffinch underwent a rapid radiation across Macaronesia that was driven by the sequential colonization of the different archipelagos, resulting in phenotypically and genetically distinct, independent evolutionary lineages. We recommend a taxonomic revision of the complex that takes into account its genetic and phenotypic diversity.
Interactions between hosts and pathogens are dynamic at both ecological and evolutionary levels. In the resultant ‘eco‐evolutionary dynamics’ ecological and evolutionary processes affect each other. For example, the house finch Haemorhous mexicanus and its recently emerged pathogen, the bacterium Mycoplasma gallisepticum, form a system in which evidence suggests that changes in bacterial virulence through time enhance levels of host immunity in ways that drive the evolution of virulence in an arms race.
We use data from two associated citizen science projects in order to determine whether this arms race has had any detectable effect at the population level in the north‐eastern United States.
We used data from two citizen science projects, based on observations of birds at bird feeders, which provide information on the long‐term changes in sizes of aggregations of house finches (host population density), and the probabilities that these house finches have observable disease (disease prevalence).
The initial emergence of M. gallisepticum caused a rapid halving of house finch densities; this was then followed by house finch populations remaining stable or slowly declining. Disease prevalence also decreased sharply after the initial emergence and has remained low, although with fluctuations through time. Surprisingly, while initially higher local disease prevalence was found at sites with higher local densities of finches, this relationship has reversed over time.
The ability of a vertebrate host species, with a generation time of at least 1 year, to maintain stable populations in the face of evolved higher virulence of a bacterium, with generation times measurable in minutes, suggests that genetic changes in the host are insufficient to explain the observed population‐level patterns. We suggest that acquired immunity plays an important role in the observed interaction between house finches and M. gallisepticum.
Aim
In temperate mountain ranges, sharp spatial variations in habitat heterogeneity and climate provide a perfect study setup to assess genetic and phenotypic differentiation in bird populations. In this paper, we analysed morphological divergence patterns across geographical and environmental gradients, in correlation with genetic differentiation and geographical isolation, in the breeding grounds of a long-distance migratory passerine.
Location
Northwestern Iberian mountains.
Taxon
The Iberian bluethroat, Luscina svecica azuricollis.
Methods
We collected a sample of 625 Iberian bluethroats across their whole breeding range to measure body weight and tarsus length, as well as wing length and pointedness. Morphological differentiation across geographical (latitude and elevation) and environmental (climate and vegetation) gradients was assessed using generalized linear mixed models. Additionally, the role of genetic distance and geographical isolation as drivers of morphological differentiation was evaluated with Mantel tests.
Results
Bird morphology varied significantly with latitude and elevation, but not with climate or vegetation. In the case of latitude, morphological differences in body size were contrary to Bergmann's rule statements. All biometric and morphometric variables diverged among localities. A similar trend was found for genetic clusters, except for wing shape. Body weight and wing length were both correlated with geographic distance, while only the former varied with genetic differentiation. The greatest genetic and phenotypic differentiation was detected in the southernmost mountain range, that holds the most geographically isolated genetic group.
Main conclusion
Evidence suggests that the strong morphological differentiation observed in the Iberian breeding bluethroat across geographical gradients results from the combination of unambiguous deterministic forces, such as ecological selection mechanisms, and other factors, such as geographical isolation, that can be either deterministic, stochastic or both, all acting at different scales.
The management of mixed municipal waste can have an impact on wildlife and ecosystems. Previous studies have investigated how opportunistic species like gulls can react very fast to new landfills; however, the impact of landfill closure on bird populations is less investigated. Yet, there is a need to understand how fast and to what extent, animal populations can be adapted to new scenarios where the waste will not be deposited in landfill sites anymore. The aim is to determine the influence of landfill closures on apparent survival of a resident Yellow‐legged Gull (Larus michahellis) population, used as a model species showing short‐distance foraging movements, and with a high dependence on local food subsidies. Complementarily, we built some basic population growth models in order to determine how potential changes in survival (before/after landfill closure) will impact on population growth rate. Using a data set of 4,437 Yellow‐legged Gull chicks ringed in four colonies over a period of 13 years, we obtained evidence supporting that the apparent survival was affected by landfill closure, especially if the landfill was located within a buffer of 10 km around the colony. Landfill closure affected the survival of first‐year gulls (with a mean decrease of ~ 0.5–0.36), but not of older birds. Consequently, we did not detect a remarkable effect of landfill closures on population growth rate, probably due to the lack of effect on adult survival rates except for one of the surveyed colonies, where we found an annual decline of 7%. Food‐waste accumulation in landfills offers the opportunity for opportunistic species to feed on it. Population trends indicate that colonies located near landfills decrease their growth capacity or directly decrease due to lack of food.