英國倫敦皇家公園呼籲公眾停止餵飼麵包給野生雀鳥如天鵝及鴨子等。因為人類令鳥類聚集導致過度擁擠及欺凌，並對牠們造成壓力及增加疾病傳播。麵包非野生鳥類的天然食物，並不能為牠們提供必須的維生素。剩下的麵包更會吸引老鼠及污染水源。

The Royal Parks in London are urging people to stop feeding bread to wild birds like swans and ducks. Human feeding is causing overcrowding and bullying among birds and leads to stress and disease spreading. Bread is not natural food for wild birds and doesn’t provide important vitamins for them; leftover bread also attracts rats and contaminates the water as well. 

https://www.theguardian.com/environment/2021/jun/10/dont-feed-the-ducks-royal-parks-warn-bullying-birds-lockdown-london-aoe