Seasonal variation in habitat use, daily routines and interactions with humans by urban-dwelling gulls

Plenty of rooftops with few neighbours occupied by young breeding Yellow‐legged Gulls (Larus michahellis): Does this occur at the expense of their health condition?

“…In our case, the urban colony of Porto had a large variation in the hatching success from 2018 to 2019 (from 56% to 88%), exactly when the distance to the nearest nest decreased from 26 to 14 m. This probably resulted from population growth, evidenced by the increase in rooftop‐nest removal requests received by Porto City Council between 2016 and 2018 (Pais de Faria et al . 2021b).…”

Fatty acids composition in yellow-legged (Larus michahellis) and lesser black-backed (Larus fuscus) gulls from natural and urban habitats in relation to the ingestion of anthropogenic materials

“…We acknowledge that some individuals in each habitat may not be strict urban or natural dwellers as we stated, because the movement ecology of each individual before capture is unknown. However, our previous research indicates that gulls from Porto are largely urban dwellers year-round (Pais de Faria et al, 2021aFaria et al, , 2021b, and those from Ria Formosa forage mostly in interaction with fishing activities also year-round (Calado et al, 2021).…”

“…In addition to other areas, PBGaia mostly serves the Metropolitan Area of Porto, where Porto is the second largest city of Portugal (PORDATA, 2011) that lies on the right side of the mouth of the Douro River, close to sea. A known population of urban gulls dwell in the city of Porto throughout the year, using certain areas of the city to rest (Pais de Faria et al, 2021a), and public and private buildings to construct their rooftop nests (Lopes et al, 2020). On the contrary, RIAS serves mostly the Ria Formosa Natural Park which has five barrier sandy islands and two peninsulas that form a narrow strip of dunes that separate the lagoon from the Atlantic Ocean (Ceia et al, 2010), and is located relatively far from metropolitan and populated urban centres.…”

“…Both YLG and LBBG, adults and immatures, males and females, are known to benefit from reliable and predictable food sources, either by interacting with fishing boats and feeding on marine species with higher nutritional value (i.e. fishery discards; Calado et al, 2018Calado et al, , 2021Mendes et al, 2018), mainly in natural habitats, or by feeding on human meal leftovers collected from trash containers or in nearby landfills, in urban habitats (Lopes et al, 2021;Pais de Faria et al, 2021a;Spelt et al, 2019). Also, in this study, we compared FA composition between adults and immature gulls (1-3 years), and we did not consider fledglings.…”

“…Large gulls Laridae, among them the yellow-legged gull (YLG; Larus michahellis) and the lesser black-backed gull (LBBG; Larus fuscus) have become more common in urban areas, with established breeding populations around the world, benefiting from a more temperate and stable microclimate and fewer natural predators than in natural habitats (Auman et al, 2008;Huig et al, 2016;Méndez et al, 2020;Pais de Faria et al, 2021a;Spelt et al, 2019). As opportunistic foragers, gulls use a wide variety of foraging habitats and strategies, being capable of exploiting different food types, especially anthropogenic food remains collected in landfills and within urban habitats (Gyimesi et al, 2016;Matos et al, 2018;Pais de Faria et al, 2021b;Parra-Torres et al, 2020;Ramos et al, 2009;Spelt et al, 2019).…”