Greylag geese have colonised urban parks across the UK, where human feeding creates welfare problems including nutritional deficiency, overcrowding and habituation to humans that removes normal behaviour.
Goslings fed bread during development may develop angel wing, preventing flight and making them permanently dependent on human-provisioned habitat. Overcrowded park waterbodies have elevated disease pressure. Geese that have lost natural flight responses cannot escape predators effectively and face reduced welfare. Dependent populations develop abnormal behaviours and reduced physical fitness compared to wild populations.