(WHTM) — Ducks are common across the country and are no stranger to Pennsylvania. People young and old love to feed them at local streams and parks. But did you know that feeding ducks certain foods can be dangerous to their health?

According to Popular Science, the common practice of feeding bread or crackers to ducks is a very dangerous thing to do, as it will endanger the well-being of the ducks. This is because bread has no nutritional benefit for the animals.

All bread does for a duck is fill them up and add nothing nutritious to their diet to help them grow. If baby birds only eat bread, they can become malnourished. and can even end up with deformities. One such case is something called angel wing, which is an incurable wing deformity that makes the ducks unable to fly.

If an adult duck eats bread and carbs, they are very likely to become sick and bloated due to the less-than-nutritious bread. Other foods you shouldn’t feed ducks include things such as:

  • Onions
    • This food can be somewhat toxic to ducks, they have an inorganic compound called thiosulfate which ducks have a hard time digesting. This compound can destroy red blood cells in ducks and cause them to be anemic, according to Metzer Farms.
  • Garlic
    • The reason for not feeding ducks garlic is the same as why you should not feed them onions.
  • Avocados
    • Metzer Farms said that avocados contain persin, which can be fatal to all ducks. All parts of an avocado should be avoided when feeding ducks.
  • Citrus and Spinach
    • These foods can interfere with calcium absorption in the duck’s body, which can cause health problems later in the duck’s life.

So, what can you feed ducks?

Popular Science says the following foods are safe to feed ducks:

  • A bag of frozen mixed peas, corn niblets, and carrot pieces.
  • Grains like oats, rice, and seeds.

The above options give all the nutrients a duck needs to survive and are easy for ducks to eat whole. You can even find specially formulated waterfowl food at your local pet store. These pellets are made for these animals.

If you have leftover stale bread, keep it inside and make something with it, rather than giving it to ducks.