Urbanization of the Silver Gull: Evidence of Anthropogenic Feeding Regimes from Stable Isotope Analyses

Auman, Heidi J.; Bond, Alexander L.; Meathrel, Catherine E.; Richardson, Amm

doi:10.1675/063.034.0108

Cited by 29 publications

(18 citation statements)

References 42 publications

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“…Among marine predators, some gull species of the genus Larus are particularly successful within the current context of human-induced global change (Vidal et al, 1998). Resource acquisition plays a major role in explaining the expansive population dynamics of these winning species (Auman et al 2011). Indeed, some gull populations have exponentially grown over the last decades, in part due to their ability to exploit food resources derived from human activities (e.g.…”

Section: Introductionmentioning

confidence: 99%

Individuals within populations: No evidences of individual specialization in the trophic habits of an opportunistic predator

Lopezosa

Forero

Ramírez

et al. 2019

Estuarine, Coastal and Shelf Science

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Human activities can affect species in different ways, with some species being unable to cope with the human-driven changes, while others can persist and even benefit from these alterations. The main factors explaining the population dynamics of successful species include their use of food resources derived from human activities and the adaptability in their feeding behavior. Among marine predators, some gull species of the genus Larus, such as the yellow-ledged gull Larus michahellis, are particularly successful within the current context of human-induced global change. While the yellow-ledged gull is considered a generalist and opportunistic predator at the population level, some individuals may show specialisation in feeding habitat and diet. Here, we examined the degree of individual specialisation in the trophic habits and temporal variation in food resource utilisation within a population of this gull in the southwestern Iberian Peninsula. We analysed the isotopic composition (d 15 N and d 13 C) in blood and different feathers molted throughout the annual cycle for reconstructing the diet of individuals and quantifying the degree of individual specialisation. Individuals of this species in the studied population preferably fed on demersal fish throughout the entire annual cycle, with a low consumption of terrestrial prey and human-related resources. Isotopic values also revealed a generalist feeding behavior in this gull species with a very small proportion of individuals acting as specialists throughout the annual cycle. Taking into account the generalist strategy of this population, management measures should mainly be focused on controlling the availability of demersal sources from fishery discards. Future research should prioritise multispecific approaches to study how general or flexible the behavior is in this winning species.

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Section: Introductionmentioning

confidence: 99%

Individuals within populations: No evidences of individual specialization in the trophic habits of an opportunistic predator

Lopezosa

Forero

Ramírez

et al. 2019

Estuarine, Coastal and Shelf Science

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“…Humans have had profound effects on past and present wildlife population demography, genetic diversity, and biogeography (Boivin et al, 2016;Erlandson et al, 2014;Grayson, 2001;Hofman et al, 2015a;Lorenzen et al, 2011;Storey et al, 2013;Zeder, 2015). A growing body of evidence demonstrates that people have also influenced the foraging ecology of ancient and modern wild animals (Auman et al, 2011;Bentzen et al, 2014;Kristan et al, 2004;Merkle et al, 2011;Newsome et al, 2010Newsome et al, , 2015bWiley et al, 2013). The diets of wild animals can be altered through intentional (direct feeding) or unintentional (scavenging of human refuse) provisioning by humans (Auman et al, 2011;Merkle et al, 2011;Newsome et al, 2010) or due to anthropogenic changes to ecosystems and resource availability (e.g., landscape clearing and burning, plant and animal introductions) (Wiley et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Tracking the origins and diet of an endemic island canid (Urocyon littoralis) across 7300 years of human cultural and environmental change

Hofman

Rick

Maldonado

et al. 2016

Quaternary Science Reviews

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Understanding how human activities have influenced the foraging ecology of wildlife is important as our planet faces ongoing and impending habitat and climatic change. We review the canine surrogacy approach (CSA)-a tool for comparing human, dog, and other canid diets in the past-and apply CSA to investigate possible ancient human resource provisioning in an endangered canid, the California Channel Islands fox (Urocyon littoralis). We conducted stable isotope analysis of bone collagen samples from ancient and modern island foxes (n=214) and mainland gray foxes (Urocyon cinereoargenteus, n=24). We compare these data to isotope values of ancient humans and dogs, and synthesize 29 Accelerator Mass Spectrometry (AMS) radiocarbon dates that fine-tune the chronology of island foxes. AMS dates confirm that island foxes likely arrived during the early Holocene (>7300 cal BP) on the northern islands in the archipelago and during the middle Holocene (>5500 cal BP) on the southern islands. We found no evidence that island foxes were consistently using anthropogenic resources (e.g., food obtained by scavenging or direct provisioning by Native Americans), except for a few individuals on San Nicolas Island and possibly on San Clemente and Santa Rosa islands. Decreases in U. littoralis carbon and nitrogen isotope values between prehistoric times and the 19 th century on San Nicolas Island suggest that changes in human land use from Native American hunter-gatherer occupations to historical ranching had a strong influence on fox diet. Island foxes exhibit considerable dietary variation through time and between islands and have adapted to a wide variety of climatic and cultural changes over the last 7300 years. This generalist foraging strategy suggests that endemic island foxes may be more resilient to future changes in resource availability.

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“…Thus, breeding sites in northwestern Australian deserts may be important for Banded Stilt population functioning, not only for their more regular filling frequencies but also their isolation from human urban population centers, which provide artificial food sources that potentially elevate Silver Gull abundance (Temby ; Auman et al. ). Strategies to mitigate the impact of Silver Gull predation at Banded Stilt nesting colonies in South Australia have included the poison baiting of gulls with Alpha Choralose at nesting colonies on certain occasions (Baxter ).…”

Section: Discussionmentioning

confidence: 99%

Long‐distance flights and high‐risk breeding by nomadic waterbirds on desert salt lakes

Pedler

Ribot

Bennett

2017

Conservation Biology

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Urbanization of the Silver Gull: Evidence of Anthropogenic Feeding Regimes from Stable Isotope Analyses

Cited by 29 publications

References 42 publications

Individuals within populations: No evidences of individual specialization in the trophic habits of an opportunistic predator

Individuals within populations: No evidences of individual specialization in the trophic habits of an opportunistic predator

Tracking the origins and diet of an endemic island canid (Urocyon littoralis) across 7300 years of human cultural and environmental change

Long‐distance flights and high‐risk breeding by nomadic waterbirds on desert salt lakes

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