The Canal and River Trust conducted a survey and found that around six million loaves of bread had been thrown into the UK’s waterways in 2014.
Bread is the equivalent of junk food, doesn’t contain much in the way of nutrients, and fills the ducks up on carbohydrates instead of eating the food they would naturally eat. Feeding ducks small quantities of bread is unlikely to be harmful but judging how small this small quantity should be is the problem. No one really knows.
However what’s more harmful is what happens when the bread is left to float around in the water for some time – algae and bad bacteria start to grow on the soggy bread, then when eaten it can cause the duck harm. Mouldy bread can also cause fatal lung infections.
Ducks will always go for the easy option and take food from humans instead of foraging, if available. This can mean ducklings won’t learn how to feed themselves, and also adults may lose their sense of fear, something which nature gave to keep them safe. Ducks are certainly charming creatures and if you still want to feed them and not miss out, the best things to give them are: corn, oats, cooked rice, or defrosted peas.