Gulls and garbage: the ecology, behaviour and physiology of a human-wildlife conflict

In response to an increasingly urbanised world, many animals have rapidly adapted to living in built-up environments. This includes two species of gull in the UK, herring- and lesser black-backed gulls, which increasingly nest and forage in close proximity to humans. This has led to growing numbers of reports of disturbance and nuisance, including direct attacks, hazards to aircraft and pathogen transmission, and subsequent control efforts. This is problematic, as both species are currently undergoing population declines. The proposed project takes a multidisciplinary approach to understand the behavioural and physiological mechanisms underlying the adaptation of herring and lesser black-backed gulls to anthropogenic environments, focusing on the role of early life experience. Early life experiences can have significant life-long impacts on many traits. Although this may be particularly relevant for gulls provisioning their chicks with diets increasingly sourced from urban areas, this has not been studied to date. For example, both diets of lower nutritional quality as well as variation in stress hormone levels associated with urban foraging may lead to changes in physiological and behavioural development of chicks. Studies in other species have suggested that such patterns may lead to "developmental programming" of offspring, so that they cope better in particular environments in later life. For gulls making increasing use of urban areas this may have strong effects on population dynamics, but this has not been studied.

The interdisciplinary project aims to: 1. Determine the extent to which birds breeding in coastal and urban environments utilise anthropogenic sites for feeding and how resultant dietary differences affect both egg hormone levels and physiological stress responses in chicks. 2. Determine the nature and consequences of behavioural and physiological differences between individuals hatching in different environments, specifically the ability of nestlings to cope with unfamiliar environments, and effects of this on chick development and foraging behaviour of juveniles. 3. Develop a model to predict how variation in early life experience (e.g. diet and subsequent physiological and behavioural differences) in different environments may affect site usage in later life and resulting population dynamics.