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 examin ed the effects of human disturbance on the population, and used this inform ation 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 respons e to disturbance. The common causes of disturbance, particularly pedestrian s, did not affect the duck greatly, but disturbances associated with buildi ng 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 win ter progressed, they did show some short-term flexibility in their response s 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 feed ing activity was not heightened following periods of exclusion from the doc ks due to disturbance. Daytime feeding activity was elevated during periods of lowering temperatures, and despite heavy disturbance at the site, the i mpact of disturbance may only be significant during the coldest period of t he 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.