It is a spring tradition to feed the local ducks bread - but it is potentially destroying their habitats and causing stress and misery.
Instead of "junk food", the Canal and River Trust says that oats, corn, or defrosted frozen peas should be fed to our feathered friends.
The trust claims that six million loaves of bread are thrown into canals and rivers every year, damaging hundreds of thousands of ducks' homes.
Soggy bread causes a unhealthy algae growth, spreads disease and encourages pests such as rats.
Feeding ducks with starchy snacks can also lead to overcrowding, stress and create excessive amounts of bird excrement.
Peter Birch, national environment manager for the Canal & River Trust, said: "Please come and feed the ducks but do it sensibly so your children and future generations can enjoy it too.
"The charity is asking the public to make a few simple changes. Bread's not great for a duck's health as it's nothing like their natural diet so don't over feed them with large quantities of it.
"Try to vary what you give them and swap it for healthier more natural treats like oats, corn, or defrosted frozen peas. And exercise portion control!
"Don't follow the crowds, spread the love, and visit a new family of ducks to prevent large quantities of the starchy duck 'junk food' from clogging up the same places and potentially damaging the environment."