Individual strategies of dabbling ducks: a circum-annual perspectice

Very little is still known about the ecology of dabbling ducks on staging areas in spring, despite the fact that this is a crucial period of the year when birds refuel during migration and prepare for subsequent reproduction. This lack of knowledge translates into the current inability to predict the consequences of changes in the environment and harvesting for the population dynamics of ducks. We have launched a joint project to study dabbling ducks in the flyway connecting wintering grounds in France with breeding areas in Sweden. The aim is to study individual dabbling ducks in a circumannual perspective. We are assessing food resource limitation, density-dependent effects and the role of competition by estimating available food, by using a reference functional response curve and by recording the foraging behaviour of wild individual dabbling ducks. We also study survival probability and breeding success, and we will assess inter-individual variation. Birds are captured, weighed, marked and subsequently observed in order to study foraging behaviour and potentially measure the changes in body mass across time through recaptures. Ducks are fitted with nasal marks for individual recognition. Eventually, we will provide a model to predict the number of young that a female duck will produce after simple measurements such as its date of arrival on the breeding grounds and its body-mass at this date. Duckling foraging efficiency and survival will be measured and the relationship with corresponding estimates for their mother will be explored.