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.

The ecology of opportunistic foragers can be highly dependent on anthropogenic food sources, such as landfills, resulting in changes in several ecological and demographic aspects. The total closure of several landfill sites and the use of deterrence systems to prevent access to the remaining open landfill sites in a region in the northern Iberian Peninsula provided an excellent opportunity to evaluate the consequences of landfills on the trophic ecology of an opportunistic forager, the Yellow‐legged Gull Larus michahellis, using these resources. Based on stable isotope analyses, we used mixing models to estimate changes in diet before and after the closure of the majority of landfills in the breeding and the non‐breeding season. We found a decrease in the consumption of food from landfills after their closure, which was accompanied by an increase in feeding on terrestrial prey (mostly earthworms), but only in the breeding season. Interestingly, we observed no increase in marine prey consumption after the landfill closures. In winter there was a decrease in terrestrial prey consumption, whereas the consumption of marine and, despite their reduce availability, landfill resources increased. Thus, and unlike when all the landfills were open, we detected significant trophic differences between breeding and non‐breeding seasons. Additionally, we found significant trophic differences among colonies that were quite close to each other, but not between breeding adults and chicks. In conclusion, landfill closure or the use of deterrence systems had a direct impact on the trophic ecology of Yellow‐legged Gulls; loss of refuse was mainly compensated for by prey of terrestrial origin when breeding, but not in winter. Thus, this species may experience foraging constraints in winter with potential effects on other life‐history aspects including their dispersal, breeding and survival that needs further evaluation.

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%.

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ResumenEn la actualidad, con el progresivo cierre de vertederos, nos situamos en un marco experimental ideal para estudiar cómo afecta la reducción drástica de un recurso trófico en la ecología, dinámica poblacional y movimientos de una especie con alto interés en la gestión, como es la gaviota patiamarilla Larus michahellis Naumann, 1840. En este contexto, en 2016 se equiparon con GPS un total de 10 ejemplares adultos de gaviota patiamarilla en una de las colonias de cría de Gipuzkoa, de los que sólo 4 proporcionaron datos hasta el 31.07.2016. El análisis preliminar aporta información básica sobre el uso del territorio durante una parte del periodo reproductor. El porcentaje de localizaciones se distribuyó de esta manera: 60% en la colonia; 18% en otro tipo de hábitats; 12% en prados y cultivos; y 6.5% en vertederos. Se detecta, así, un relativo alto uso de los prados y cultivos del entorno de la colonia, así como de dos de los vertederos más importantes de la región. Por otro lado, parece existir alta variabilidad individual en el uso del territorio que podría reflejar diferentes estrategias en la búsqueda de alimento.Palabras clave: Dispositivos GPS, ecología espacial, especies oportunistas, Gipuzkoa, vertederos. AbstractToday, the progressive closure of landfills provides a good opportunity to study how this affects the drastic reduction of a food resource on the ecology, population dynamics and movement patterns of opportunistic species, such as the yellow-legged gull Larus michahellis Naumann, 1840. Against this background, in 2016, we captured 10 adult breeding gulls in one of the main breeding colonies in Gipuzkoa. These individuals were equipped with a GPS device. Only four of them provided data up to the end of the breeding period (31.07.2016). Preliminary analyses provide basic information about spatial use and trophic habitat during the breeding period (colony: 60%; other habitat types: 18%; grasslands/crops: 12%; dumps: 6,5%). An apparently relatively high use of grasslands and crops is confirmed, as well as the use of two of the largest landfills in the region. We also observed a very high individual variation in territory use, which might reflect different foraging strategies.Key words: GPS device, spatial ecology, opportunistic species, Gipuzkoa, dumps. LaburpenaEgun, urratsez urrats zabortegiak ixten ari direlarik, testuinguru esperimental ezin hobean gaude ikertzeko nola eragiten dion baliabide trofiko baten erabateko murrizketak maila ekologikoan, populazio dinamikan eta mugimenduetan, baliabide horren kudeaketarekin lotura handia duen kaio hankahoriari, Larus michahellis Naumann, 1840.