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Fishing activity generates high amounts of fishing discards, a predictable anthropogenic food subsidies used by seabirds. Although the use of discards by these predators has been well studied, there is a lack of knowledge about the ontogenetic differences in their use. We contributed to filling this gap for the yellow-legged gull (Larus michahellis), an opportunistic predator that extensively exploits anthropogenic food subsides. We investigated its foraging behaviour during the early breeding season deploying GPS devices on adults, immatures, and juveniles from the urban population of Barcelona (northwestern Mediterranean Sea) and examining the effect of fishing vessels on their spatial movements using a Vessel Monitoring System. The results revealed age-related differences in distribution and foraging behaviour at sea and an interaction with fishing vessels in this seabird. Age-related differences in behaviour were explained by the reproductive constraints of adults and the ontogenetic differences associated with lower foraging ability in immature and juvenile individuals. We did not find apparent preferences for a specific type of fishing vessel between ages. These results suggest that the reform of the Common Fisheries Policy might affect the entire population of this species, that could lead to an increase in the use of urban environments, increasing the conflicts with human activities

Interest in plastic contamination in inland aquatic environments due to human activity has been growing greatly. The amount of plastic produced generates severe environmental problems, due to long term deposition, but also because plastic breaks down into smaller pieces that persist and interact with aquatic biota. Many waterbirds (e.g. gulls) have shifted their natural behaviour to exploit constant anthropogenic resources (e.g. rubbish dumps) and may be biovectors of plastics and nutrients between terrestrial and aquatic environments. In south-west Spain Lesser black backed gull (Larus fuscus) and yellow legged gull (Larus michahellis) are opportunistic species exploiting resources at dumps and biovectoring plastics to natural environments (e.g. at Fuente de Piedra Lagoon and Odiel marshlands respectively) through pellet and faecal deposition. However, the role of gulls as plastic vectors has not been quantified so far. Using movement data acquired with GPS devices, combined with censuses and analysis of pellets and faeces collected from the wetlands, we quantify the amounts of plastics, other debris, and nutrients imported by gulls into these two internationally important wetlands. We consider possible management measures to reduce the extent of these biovectoring processes

El abaratamiento y la gran oferta de dispositivos de GPS en el mercado ha incrementado en los últimos años la posibilidad de realizar estudios de seguimiento y marcaje de fauna salvaje a una escala sin precedentes. Lo anterior, unido a la facilidad y disponibilidad de datos de seguimiento de los movimientos y actividad de los barcos de pesca, ya sean AIS (sistema de identificación automática - automatic identification system) o VMS (sistema de localización de barcos - vessel monitoring system), y al uso de herramientas de software libre, nos permite estudiar las interacciones entre la ecología de búsqueda de alimento de depredadores marinos y las actividades humanas en el medio marino. Un aspecto relevante de conocer la ecología de los animales marinos es poder evaluar el impacto que la introducción de medidas de gestión puede tener sobre estos animales. El objeto de este trabajo ha sido contribuir a llenar una parte de ese vacío de conocimiento relativo a la gaviota patiamarilla (Larus michahellis), depredador marino oportunista que tiene la capacidad de explotar diferentes recursos de origen humano, por lo que es muy conocido en las ciudades de la costa mediterránea. En este sentido, se ha investigado la ecología de búsqueda de alimento en el mar de esta especie mediante la instrumentación con dispositivos GPS de individuos juveniles, inmaduros y adultos de la población urbana de Barcelona. Además, se han caracterizado sus áreas de alimentación y el comportamiento asociado al medio marino. También se ha determinado la interacción con las flotas de pesca de cerco y arrastre, al relacionar los movimientos de las gaviotas con los movimientos de las embarcaciones mediante los datos VMS y los de los GPS de las gaviotas. Los resultados han evidenciado diferencias entre edades, tanto en la distribución espacial como en los diferentes comportamientos de búsqueda de alimento, relacionadas con distintos factores biológicos complementarios como sería la época de cría. Así, l

The yellow-legged gull is an opportunistic and generalist bird that has colonised urban areas, where it has found very favourable trophic resources but also causes disturbance to humans and damage to infrastructure. Here, we investigated the potential role that gulls play in the dispersal of plants in Barcelona, a highly populated city of north-eastern Spain. We analysed the stomach contents of 145 chicks collected in urban nests and reported the presence of seeds of 27 plant taxa. We then developed a plant dispersal model based on the movements of 20 GPS-tracked yellow-legged gulls breeding in the city of Barcelona. We estimated seed dispersal distances, seed shadows and percentage of seeds reaching habitats suitable for seeds regurgitated in pellets and those excreted in faeces. Seven of the 27 plant taxa found in the stomachs were alien taxa to Spain. Average dispersal distances of plant seeds by gulls were around 700 m, but maximum dispersal distances reached up to 35 km. Dispersal distances and seed spatial patterns did not differ between faeces and pellet models, as most strongly depended on gull movements. About 95% of the seeds were dispersed within urban environments and between 20 and 30% reached suitable habitats for seed deposition (urban woodlands, green urban parks and urban grasslands). Urban gulls frequently dispersed seeds (including alien species) within urban habitats, both via direct consumption or via secondary dispersal after consuming granivorous birds that had ingested the seeds, such as pigeons or parakeets. Urban planning for Barcelona is based on native plant species, and thus, special attention should be paid to alien plants dispersed by birds, which could pose a risk to native biodiversity in urban ecosystems

[EN] The oceans cover about 71% of the Earth’s surface and contain about 97% of the living space on the planet and somewhere between 500000 and 10 million different species. Oceans provide humans with natural benefits such as seafood provisioning, carbon storage and climate regulation –the so-called ecosystems services. However, despite their paramount importance for the maintenance of life and human wellbeing, oceanic systems are among the most complex, poorly understood and impacted biomes. […], [ES] Los océanos cubren aproximadamente el 71% de la superficie de la Tierra, representan el 97% del espacio habitable del planeta, y alojan entre 500.000 y 10 millones de especies marinas. Los océanos son también una incalculable fuente de beneficios para los humanos, ofreciéndonos múltiples servicios ecosistémicos: constituyen una de las principales fuentes de alimentos y juegan un papel fundamental en el ciclo del carbono y en la regulación del clima. A pesar de su importancia en el mantenimiento de la vida y el bienestar humano, los océanos se encuentran entre los biomas de la Tierra más complejos, desconocidos e impactados por la presión del clima y las actividades humanas. […], [CAT] Els oceans cobreixen aproximadament el 71% de la superfície de la Terra, representen el 97% de l’espai habitable del planeta, i allotgen entre 500.000 i 10 milions d’espècies marines. Els oceans són també una incalculable font de beneficis per als humans, oferint-nos múltiples serveis ecosistèmics: constitueixen una de les principals fonts d’aliments i juguen un paper fonamental en el cicle del carboni i en la regulació del clima. Malgrat la seva importància en el manteniment de la vida i el benestar humà, els oceans es troben entre els biomes de la Terra més complexos, desconeguts i impactats per la pressió del clima i les activitats humanes. […]

Foraging distribution of flying seabirds is constrained by environmental factors influencing individual decision-making. This must be particularly true during the breeding period, when individuals face additional limitations imposed by their central-place foraging behaviour. We used GPS data loggers and Argos PTTs to track the foraging flights of Balearic shearwaters (Puffinus mauretanicus) during the chick-rearing period of 2011–2014 in the Balearic Islands (Western Mediterranean). We identified main areas used by tracked birds and characterised their productivity patterns. Based on a spatial seascape approach of flight costs varying with time, shaped by environmental processes as winds, we also estimated flight costs to reach foraging grounds in outward and return trips from the colony. Individuals repeatedly used the closest areas on the Iberian continental shelf. However, sporadic and favourable wind conditions facilitated low-cost flight to more distant and equally productive areas of the western North African shelf

Increasing human activities have detrimental consequences on marine ecosystems and their impact can have cumulative effects. Within marine ecosystems, seabirds respond to ecosystem variability and face multiple human pressures, especially threatened species. In long-lived species, juveniles and immatures could represent up to 50% of the total population, but their migratory movements remain largely unknown. Here, we depict the migratory patterns of juvenile Balearic shearwaters Puffinus mauretanicus, the most threatened European seabird, using miniaturised satellite transmitters. At the end of the 2012 breeding season, five tagged juveniles left the breeding colonies of Eivissa Island (western Mediterranean) the first week of July. They moved westwards to reach the Atlantic Ocean between 3 and 13 days afterwards. Juveniles showed a twophase migratory pattern: they first travelled slower close to the breeding colonies, and then moved towards their wintering areas in the Atlantic Ocean by rapid directional movements. Environmental cues (e.g.,marine productivity, water mass distribution, frontal systems) might have a prominent role in driving the migratory patterns of juvenile Balearic shearwaters, moving from warm and poor marine areas in the Mediterranean Sea to cooler and rich non-breeding grounds in the Atlantic Ocean. Based on observational findings, we observed certain spatial overlap of juvenile Balearic shearwaters with areas of high human impact, but the relationship between flying travel speed and both fishing effort and cumulative human impacts were not statistically significant. These results suggest that more research is needed to assess whether the movement patterns of migrating juveniles are affected by human activities. Therefore, understanding the at-sea spatial ecology of juveniles should be a priority for research and conservation due to the importance of this population component in long-lived species, as well as assessing their vulnerability to mul

In the scope of the Copernicus Hyperspectral Imaging Mission (CHIME) support activity, absolute radiometric field measurements were carried out to cross-calibrate data response of the airborne AVIRIS-NG, spaceborne DESIS and PRISMA, and UAV hyperespectral sensors. Near-simultaneous field spectral data were collected at invariant targets in Doñana National Park and Ríotinto mining area (Huelva, Spain) on 25 June 2021. Sand dune surface and uniform benign residuals of treated mine waste were selected as invariant target sites, respectively. These dataset consists of the field spectral data. High spectral resolution field surface reflectance data were acquired using the Analytical Systems Devices (ASD) spectrometers measuring between the visible (VIS) to short wave infrared (SWIR) (400-2500 nm) ranges within ± 1 hour from the airborne data acquisition, which occurred at local noon. Collection methodology is described in Malthus, Ong et al. 2019. Inter-comparisons between these sensors are being examined as a precursor to raw materials and natural resources managements applications

Research focused on evaluating how human food subsidies influence the foraging ecology of scavenger species is scarce but essential for elucidating their role in shaping behavioral patterns, population dynamics, and potential impacts on ecosystems. We evaluate the potential role of humans in shaping the year-round distribution and habitat use of individuals from a typical scavenger species, the yellow-legged gull (Larus michahellis), breeding at southwestern Spain. To do this, we combined longterm, nearly continuous GPS-tracking data with spatially explicit information on habitat types and distribution of human facilities, as proxied by satellite imagery of artificial night lights. Overall, individuals were mainly associated with freshwater habitats (mean proportion, 95% CI: 40.6%, 36.9%–44.4%) followed by the marinerelated systems (40.3, 37.7%–42.8%), human-related habitats (13.5%, 13.2%–13.8%), and terrestrial systems (5.5%, 4.6%–6.5%). However, these relative contributions to the overall habitat usage largely changed throughout the annual cycle as a likely response to ecological/physiological constraints imposed by varying energy budgets and environmental constraints resulting from fluctuations in the availability of food resources. Moreover, the tight overlap between the year-round spatial distribution of gulls and that of human facilities suggested that the different resources individuals relied on were likely of anthropogenic origin. We therefore provide evidence supporting the high dependence of this species on human-related food resources throughout the annual cycle. Owing to the ability of individuals to disperse and reach transboundary areas of Spain, Portugal, or Morocco, international joint efforts aimed at restricting the availability of human food resources would be required to manage this overabundant species and the associated consequences for biodiversity conservation (e.g., competitive exclusion of co-occurring species) and human interests (e.g., a

Background: Human activities have profoundly altered the spatio-temporal availability of food resources. Yet, there is a clear lack of knowledge on how opportunistic species adapt to these new circumstances by scheduling their daily rhythms and adjust their foraging decisions to predicable patterns of anthropic food subsidies. Here, we used nearly continuous GPS tracking data to investigate the adaptability of daily foraging activity in an opportunistic predator, the yellow-legged gull (Larus michahellis), in response to human schedules. Methods: By using waveform analysis, we compared timing and magnitude of peaks in daily activity of different GPS-tracked individuals in eleven different habitat types, in relation to type of day (i.e., weekday vs. weekend). Results: Daily activity rhythms varied greatly depending on whether it was a weekday or weekend, thus suggesting that gulls’ activity peaks matched the routines of human activity in each habitat type. We observed for the first time two types of activity as modelled by waveforms analysis: marine habitats showed unimodal patterns with prolonged activity and terrestrial habitats showed bimodal patterns with two shorter and variable activity peaks. Conclusions: Our results suggest that gulls are able to fine-tune their daily activity rhythms to habitat-specific human schedules, since these likely provide feeding opportunities. Behavioral plasticity may thus be an important driver of expansive population dynamics. Information on predictable relationships between daily activity patterns of gulls and human activities is therefore relevant to their population management

Time Series water turbidity derived from Landsat TM, ETM+ & OLI in the Path 202 Row 34 (Doñana). Also, the product and its metadata are freely available to consult or downloaded in the LAST-EBD Cartography Server: http://mercurio.ebd.csic.es/imgs/ Teh methodology is described in the paper: Empirical models to estimate water turbidity from reflectance data from TM or ETM+ Landsat sensors in shallow wetlands such as Doñana marshes. See the reference: Bustamante, J. et al. 2009. Predictive models of turbidity and water depth in the Doñana marshes using Landsat TM and ETM+ images. Journal of Environmental Management. 90:2219-2225.https://doi.org/10.1016/j.jenvman.2007.08.021

Scheduled routines of human activities can modify feeding behaviour of opportunistic and generalist scavenger species, that largely rely on anthropogenic food subsidies. Here, we used GPS tracked technology to investigate the adaptability of daily foraging activity in the yellow-legged gulls (Larus michahellis) in response to human weekly working schedule. By waveform analysis, we compared timing and magnitude of peaks in activity of 18 individuals breeding at the “marismas del Odiel” (Huelva, Spain) in 11 different habitats types, in relation to the day of the week (i.e. working day vs. weekend). We observed two types of activity model waveforms (unimodal and bimodal) in marine and terrestrial habitats. Marine habitats showed unimodal patterns with and more prolonged activity. Terrestrial habitats showed bimodal patterns with two shorter and variable activity peaks. Gulls activity peaks matched the schedules of human activity at each habitat type, to the point that the daily activity rhythms vary greatly depending on whether it is a working day or weekend. Our results suggest that gulls are able to fine-tune their daily activity rhythms to habitat specific human activities since these likely provide feeding opportunities, being that behavioral plasticity a driver of seagull expansive population dynamics. Information on predictable relationship between daily activity patterns of gulls upon human activities is of relevance for their population management

Wildlife that exploit human-made habitats hosts and spreads bacterial pathogens. This shapes the epidemiology of infectious diseases and facilitates pathogen spill-over between wildlife and humans. This is a global problem, yet little is known about the dissemination potential of pathogen-infected animals. By combining molecular pathogen diagnosis with GPS tracking of pathogen-infected gulls, we show how this knowledge gap could be filled at regional scales. Specifically, we generated pathogen risk maps of Salmonella, Campylobacter and Chlamydia based on the spatial movements of pathogen-infected yellow-legged gulls (Larus michahellis) equipped with GPS recorders. Also, crossing this spatial information with habitat information, we identified critical habitats for the potential transmission of these bacteria in southern Europe. The use of human-made habitats by infected-gulls could potentially increase the potential risk of direct and indirect bidirectional transmission of pathogens between humans and wildlife. Our findings show that pathogen-infected wildlife equipped with GPS recorders can provide accurate information on the spatial spread risk for zoonotic bacteria. Integration of GPS-tracking with classical epidemiological approaches may help to improve zoonosis surveillance and control programs

The study of juvenile migration behaviour of seabird species has been limited so far by the inability to track their movements during long time periods. Foraging and flying skills of young individuals are assumed to be inferior to those of adults, making them more vulnerable during long-distance migrations. In addition to natural oceanographic effects and intrinsic conditions, incidental seabird harvest by human fisheries is one of the main causes of worldwide seabird population declines, and it has been hypothesized that juveniles are particularly vulnerable to bycatch during their first weeks at sea after leaving the nest. We used solar-powered satellite tags to track the at-sea movements of adults and juveniles of Scopoli's shearwater (Calonectris diomedea) after the autumn departure from their breeding colony in Chafarinas Islands (southwestern Mediterranean Sea). Eighty per cent of juvenile tags stopped transmitting during the first week at sea, within 50 km of their natal colony, in an area with one of the highest concentrations of fishing activities in the Mediterranean Sea. All adult birds tagged and only 20% of juveniles migrated into the Atlantic and southwards along the coast of West Africa. The two age groups showed different habitat preferences, with juveniles travelling farther from the coast, in windier and less productive waters than adults. We conclude that Scopoli's shearwater juveniles are particularly vulnerable to mortality events, and we highlight that fisheries, along with differential age-related behaviour skills between adults and juveniles, are likely causes of this mortality. Overall, our study highlights the importance of conducting tracking studies during the first stages of juvenile migration

Waterbird communities are potential indicators of ecological changes in threatened wetland ecosystems and consequently, a potential object of ecological monitoring programs. Waterbirds often breed in largely inaccessible colonies in flooded habitats, so unmanned aerial vehicle (UAV) surveys provide a robust method for estimating their breeding population size. Counts of breeding pairs might be carried out by manual and automated detection routines. In this study we surveyed the main breeding colony of Glossy ibis (Plegadis falcinellus) at the Doñana National Park. We obtained a high resolution image, in which the number and location of nests were determined manually through visual interpretation by an expert. We also suggest a standardized methodology for nest counts that would be repeatable across time for long-term monitoring censuses, through a supervised classification based primarily on the spectral properties of the image and a subsequent automatic size and form based count. Although manual and automatic count were largely similar in the total number of nests, accuracy between both methodologies was only 46.37%, with higher variability in shallow areas free of emergent vegetation than in areas dominated by tall macrophytes. We discuss the potential challenges for automatic counts in highly complex images.

Spring sea ice phenology regulates the timing of the two consecutive pulses of marine autotrophs that form the base of the Arctic marine food webs. This timing has been suggested to be the single most essential driver of secondary production and the efficiency with which biomass and energy are transferred to higher trophic levels. We investigated the chronological sequence of productivity pulses and its potential cascading impacts on the reproductive performance of the High Arctic seabird community from Svalbard, Norway. We provide evidence that interannual changes in the seasonal patterns of marine productivity may impact the breeding performance of little auks and Brünnich’s guillemots. These results may be of particular interest given that current global warming trends in the Barents Sea region predict one of the highest rates of sea ice loss within the circumpolar Arctic. However, local- to regional-scale heterogeneity in sea ice melting phenology may add uncertainty to predictions of climate-driven environmental impacts on seabirds. Indeed, our fine-scale analysis reveals that the inshore Brünnich’s guillemots are facing a slower advancement in the timing of ice melt compared to the offshore-foraging little auks. We provide a suitable framework for analyzing the effects of climate-driven sea ice disappearance on seabird fitness