How Do Cardinals Use Glucose to Survive?

how do cardinals use glucose to survive

Cardinals use glucose as stored energy. During cellular respiration, they use up the energy inside the glucose to stay active and warm.

Carbohydrates are an important part of Northern Cardinal’s diet. Glucose, a simple sugar, is especially important in the winter.

Read on to learn more about how cardinals need carbohydrates and which glucose-rich foods you can place in their bird feeder.

What Is Glucose?

Glucose is a simple sugar, also called a monosaccharide. It is the main source of energy in animals, including birds.

Glucose is made by plants as a product of photosynthesis. Plants then transform the glucose into starch which is the main source of energy for plants.

When humans and animals consume a food containing starch, the body breaks down the starch into either glucose or glycogen. Glycogen is the form of glucose that is stored in our body, ready for energy release when the body needs it.

Why Do Cardinals Need Glucose in Winter?

Cardinals need glucose year-round but it is extra important during cold winters. They need the glucose for energy – to be able to hop around, fly, breed, build nests etc.

In the fall, non-migratory birds increase their food intake to build a thicker layer of fat which helps to keep them warm in the winter. Cardinals look for energy-rich foods so that they can better survive the winter when food is scarce.

Which Glucose-Containing Foods Can Cardinals Eat?

Glucose is a carbohydrate in its simplest form. The digestive system of cardinals will break down complex carbohydrate foods into glucose.

Below is a list of foods containing glucose that are also safe for cardinals to eat.

What Not to Feed Cardinals

Although cardinals need glucose for energy, too much glucose is not healthy for them, either. Like in humans, eating too many sugary foods can cause diabetes mellitus.

That is why you should be selective in the types of carbohydrates you put in the bird feeder. Even foods that may not seem too sugary, such as bread, are not the best food source for small birds.

A general rule of thumb is to only provide foods that they would naturally eat in the wild. This removes any processed foods from the list, including certain pre-made bird feeder mixes.

Examples of foods not to feed cardinals include:

  • Bread
  • Microwave popcorn
  • Honey
  • Baked goods
  • Potato chips
  • Dairy products

Frequently Asked Questions:

What Do Cardinals Eat?

Cardinals are omnivores, they eat insects but also seeds, fruit and certain parts of plants. They love to eat sunflower and safflower seeds, berries, peanuts and insects such as beetles and grasshoppers.

How Can Starch in Sunflower Seeds Help Cardinals Survive the Winter?

Sunflower seeds are rich in carbohydrates. In preparation for winter, cardinals eat excessive amounts of food, including seeds, so that the carbohydrates are stored in their body as fat. The extra layer of fat acts as insulation against the cold of winter.

How Can You Help Cardinals Survive the Winter?

The best way to help cardinals survive a cold winter is providing them with enough sources of food. Place bird feeders in your yard, preferably near bushes and where there isn’t much foot traffic.


Glucose, the simple sugar in carbohydrates, is an important element in the diet of cardinals. It is a source of energy year-round but in the winter it serves an extra function.

During the fall, Northern Cardinal birds fatten themselves up by eating foods rich with carbohydrates and protein. The extra layer of food keeps them warm in the winter and the storage of glucose provides them with a source of energy when food sources are scarce.

Humans can support Northern Cardinal populations by placing winter bird feeders in their backyard. Excellent foods for cardinals include sunflower seeds, safflower seeds, suet and peanuts.

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