Impact of Disturbance on Waterfowl Wintering in a UK Dockland Redevelopment Area

One of the UK's largest flocks of pochard Aythya ferina and tufted duck A. fuligula winters in Manchester's busy dockland redevelopment area. I examined the effects of human disturbance on the population, and used this information to recommend minimal land-use restrictions that will help ensure the population's continued use of the site. Birds fed at the docks every night, but on 75% of days, the flock flew to suburban or rural refuges in response to disturbance. The common causes of disturbance, particularly pedestrians, did not affect the duck greatly, but disturbances associated with building and redevelopment of the site (e.g., machinery) often made duck evacuate the dock. While birds were no less likely to evacuate the docks as the winter progressed, they did show some short-term flexibility in their responses to disturbance. For example, birds appeared able to sit out disturbances throughout the afternoon if they had avoided evacuation of the docks during the morning. Birds spent only a small proportion of time feeding, and feeding activity was not heightened following periods of exclusion from the docks due to disturbance. Daytime feeding activity was elevated during periods of lowering temperatures, and despite heavy disturbance at the site, the impact of disturbance may only be significant during the coldest period of the winter. During very cold spells, it is important to limit the incidence of unusual disturbances, such as evening concerts and waterborne activities which tend to make duck evacuate the site.