Manitoba bird experts are warning the public to think twice about feeding bread to wild birds after two mallards were seen at Winnipeg’s St. Vital Park with signs of a condition known as angel wing — a syndrome that affects aquatic birds like ducks and geese and can permanently deform their wings.

Angel wing is caused by a nutritional deficiency that comes from humans feeding wild birds foods high in carbohydrates and sugar, such as bread.

“As a result, the growing feathers are too heavy and cause the bone to start hanging and twisting outwards,” said Angie Furniss, rehabilitation manager at Wildlife Haven Rehabilitation