Bird Respiratory System: Amaze-wing Facts On Respiration For Kids

Birds are classified as omnivorous vertebrates, as they survive on both plant and animal-based food, and have a spinal cord that controls their nervous system.

Most of their body functions and structure are similar to mammals, but scientists have discovered that whilst the respiratory system of birds is mostly similar to that of mammals, it is actually quite sensitive.

It is believed that birds have the best and most efficient respiratory systems. There are some organs in a bird's respiratory system that cannot be found in mammals, which makes it easier for the birds to consume a lot of fresh air to generate the energy required for flying.

Paired lungs and connected air sacs make up the respiratory system of a bird.

After reading this article which reveals facts about the thin-walled air sacs present inside the lungs of a bird, why not check our macaw facts and our fascinating facts about bantam breeds.

How does a bird's respiratory system work?

Birds have a four-chambered heart like mammals and a set of lungs in their respiratory system. But apart from the lungs, these species also have several air sacs instead of a diaphragm, which help them hold larger amounts of air when breathing.

The air sacs also ensure that only fresh air or oxygen-rich air passes through the lungs, hence the level of oxygen intake in the avian respiratory systems is much higher compared to mammalian lungs.

When a bird inhales air through its nose, or more aptly the opening called nares, this air passes through the trachea, which separates into two bronchi openings. The lung tissues in birds are made from thousands of bronchi air capillaries which are then connected to the posterior air sacs.

The fresh air full of oxygen travels through the air capillaries of bronchi to the posterior air sacs, and they expand as the bird inhales.

When the bird exhales during breathing, the air sacs deflate, and due to that pressure, the air moves from the posterior air sacs to the inside of the lungs and then from the lungs, the air pumped into the heart and blood.

During double respiration in birds, air passes twice through the lungs allowing for double absorption of oxygen.

When the bird inhales again, this filtered, or used air which contains carbon dioxide gets pushed into the anterior air sacs after another expansion and then moves back through the trachea and out of the nose on the final step of exhalation of one whole breath.

Hence, unlike mammals who have a bidirectional pattern of respiration, birds breathe in a unidirectional manner.

Why do birds have one of the most efficient respiratory systems?

Unlike in mammals or human beings, the airflow that occurs in the respiratory system of birds is unidirectional, i.e. the air flows in a single direction without getting mixed with impure or used air.

During this process, the sternum moves forward and downward. As explained above, a single breath of air remains in a bird’s body for two consecutive respiration cycles, hence birds gain a lot of energy out of the air they breathe compared to humans and other animals.

These air sacs which are spread in almost the whole of the avian body enable them to intake a huge amount of air compared to their small sizes. Compared to the human respiratory system, which takes up only one-twentieth of the body, a bird’s respiratory system takes up at least one-fifth of its bodily system.

Humans complete one cycle of breathing in a two-step process of inhalation and exhalation, whereas birds have a four-step process that includes two inhalations and two exhalations to complete a single cycle of breathing.

This is what makes them super-breathers. In addition, the respiratory tract which includes air capillaries and numerous air sacs ingeniously separates the fresh blood from the stale blood and passes it through the lungs only once, when it is full of oxygen.

Surrounded by capillary networks, alveoli are the sites for gas exchange, oxygen, and carbon dioxide. The air that has been inhaled travels down every primary bronchus and is then divided.

This air, which is now mostly composed of carbon dioxide, does not mix with the fresh air as it does with mammals, who always have some impure air in their lungs which they do not exhale. Only fresh air remains in the bird’s body giving it an advantage of purer air circulating through its body.

During ventilation in birds, no residual air is left in either lung.

How does a bird's respiratory system enable them to fly?

A bird’s respiratory system is composed of organs, which facilitate the inhalation of air through the trachea, which passes through the bronchi to get separated into thousands of different air capillaries of bronchi. This air goes directly through the lung to the posterior air sacs.

From there, due to the expansion and dilation of the lung muscles and air sacs caused by inhalation and exhalation of the bird, the air goes through the lungs to the anterior air sacs, and from then lungs it exits through the trachea again.

A bird’s body is anatomically adapted perfectly for flight. Due to its air sacs, a bird is able to draw in a lot of oxygen which generates the energy which a bird needs to fly.

As only fresh air full of oxygen can enter the lungs, the bird obtains a large amount of air compared to other animals and human beings who have a bidirectional respiration system.

The extensive amount of energy that occurs from the air they breathe through the lungs powers the muscles of the chest and feathers, which help them fly. Also, more oxygen ensures that pure blood flows and that it reaches every tissue of a bird’s body to give them more energy.

What is special about bird bones?

In a bird, the bones are extremely light so as to help the bird fly from the ground with ease, yet still support its weight in flight.

The bones in a bird’s body are generally hollow, which reduces a lot of weight compared to other mammals and human beings. Also, instead of heavy teeth and jawbones for a mouth, birds have beaks, which are made from a similar substance which forms our nails.

These beaks are lightweight but strong for applying pressure for breaking hard nuts or even using them as a weapon in fights. There are certain special struts inside a bird’s hollow bones, which makes them stronger compared to mammals.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for bird respiratory system: amaze-wing facts on respiration for kids then why not take a look at bald eagle Vs golden eagle: a difference fact guide between two eagle, or chameleon lifespan: interesting facts on their age revealed!