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Important biological parameters, such as movement and survival, can differ substantially between sexes, driving the demographic patterns of a population. Sex-dependent spatial segregation at the foraging grounds can evolve as a mechanism to reduce competition for resources between sexes, among other causes. Investigating such segregation, especially in scenarios of decreasing food availability, can contribute to understanding how birds adapt to a fast-changing world. The aim of the present study was to determine whether year-round movements and survival varied between sexes within a resident Yellow-legged gull Larus michahellis population. To this end we used live encounter data on colour-ringed Yellow-legged Gulls in northern Spain in the period 2009–2017. We used Generalized Linear Models to analyse distance to the colony of origin and multi-state models to estimate both survival and year-round movements, which did not provide evidence supporting an effect of sex on movement and survival. In contrast, distances travelled from the natal colony varied between seasons and all gulls were more likely to move greater than 100 km from natal sites. Juveniles showed lower survival rates (0.55) than older birds (0.90). Future research with GPS data might help to reveal, if existing, the occurrence of local spatial segregation between sexes that otherwise remains undetected. [ABSTRACT FROM AUTHOR]

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Determining the age of specimens is of great help in wildlife management, especially for rare or threatened species in which each individual has a high value. In birds, differences in moulting pattern between juveniles and adults may in some cases allow determination of a bird's age from the examination of its plumage. In the present study, we analyse the moult of 19 breeding individuals of White-backed Woodpecker Dendrocopos leucotos lilfordi captured for GPS tagging in the Pyrenees, in order to describe, for the first time, the moulting pattern of this endangered woodpecker. Two well-differentiated groups of adult birds were identified: those that underwent a partial moult, and were classified as second-calendar-year birds, and those that performed a complete one and were classified as older. The first group had renewed most lesser and median coverts, all primaries and the innermost greater coverts, thus showing clear moult limits between the primaries and secondaries and within the greater coverts. Some individuals also replaced up to two more greater coverts (GC5–6). Individuals classified as older birds showed all feathers to be of a single generation, indicating that they had undergone a complete moult. A few individuals in this category retained a few unmoulted secondaries and primary coverts, however. A recapture of a bird with a complete moult, which had been captured a year before showing a partial moult, would confirm these moult sequences to be age dependent. This moulting pattern is very similar to that described for other spotted woodpeckers, and allows researchers to determine the ages of breeding individuals during the nesting season. [ABSTRACT FROM AUTHOR]

Copyright of Ardeola is the property of Sociedad Espanola de Ornitologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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. [ABSTRACT FROM AUTHOR]