The Basics of Bird Anatomy

When it comes to bird anatomy, most pet bird owners have no clue about how the organs work and how the skeletal system is formed. You might not think this topic is interesting or even relevant, but it is very complex, and if you are wanting to care better for your birds, there are some basics you should know.

The Basics Of Bird Anatomy

Here I will be looking mainly at a cockatiel’s bird anatomy as this website is mainly focussed on cockatiels, but a lot of the bird anatomy discussed here applies to all the parrot species.

Respiratory System

Cockatiels have a high oxygen demand because of their high metabolic rate. This means that they have a respiratory system that is much more efficient than the one a mammal or reptile has.

The respiratory system is divided into lungs and airbags and serves them well in their capability to fly.

The trachea divides into two bronchi. The lungs themselves are small and spongy-like. One of the interesting characteristics of the respiratory system are the air sacks. Their mission is to dissipate liquids and restore the gasses that the bird breathes.

As the liquids dissipate, the cockatiel can somewhat control his body temperature and prevent it from rising too much. As a bird breathes, air flows through the lungs to the air sacks in the tempo of the movement of the ribs and sternum – going through the vasculature twice.

As the bird flies the muscles moving the wings cause the air sacks to widen and shrink and this causes the air to rotate between the lungs and airbags.

Circulatory System

When it comes to their circulatory system, birds have a four-chambered heart, which is the same as most mammals. This means that they can get nutrients to their body as well as oxygen very easily.

A bird’s heart is going to beat much more quickly that a mammals heart, due to what they have to do to survive. They need much more oxygen in their blood to help them with flight.

Digestive System

The digestive system of birds is very interesting. Most of them have a muscular pouch that is called a crop which is formed along their esophagus.

It helps them to soften food, as well as regulates the flow of that food through the bird’s system because the food can be stored in this pouch and used as needed.

Skeletal System

The Skeletal system of a bird is interesting as well. Because the bird is intended to fly, the skeleton is adapted for this. It is very lightweight, which would allow the bird to get off the ground. On the other hand, it is very strong and pliable, so that it doesn’t break when a bird takes off or lands.bird anatomy

The bones are hollow in order to allow them to be lightweight.

Cockatiel’s sternum is quite flat, but the other side is more protruding and attached to the chest muscles. If you can’t feel the sternum with your finger, the cockatiel is probably overweight. If you can feel it too clearly, the bird is probably too skinny.

The breast bone is not very flexible in birds.

There are five lumbar vertebrae fused together, thus making the cockatiels back quite stiff as well.

Instead, the neck of the bird is very flexible thus you see it sleeping with its head turned backward with its beak embedded in its back feathers.

The skull is attached to the vertebra with one condyle that is formed from bones that are fused together. The mission of the skull is to protect the brains that are located inside the round-shaped braincase. The eye sockets are very large. The length of the skull is around 2,2-2,7cm.

Cockatiels don’t have teeth. Instead, they have a hooked beak.

The tail is attached to a stub tailbone called the pygostyle.

The forelimbs were developed through evolution and formed as wings.

Looking at the wing bone structure, you can see the same elements as the human hand would have. The wing has three fingers: the thumb, middle finger and ring finger, although these are clearly atrophied.

The legs and feet are developed for multitasking. Cockatiels use their feet to move, sit, scratch and catch objects.

The femur is very short, unlike ours which is the longest bone in the body. The knee of the bird is hidden amongst the feathers. The tibia and instep are longer. So, unlike mammals that use mostly the knee to refract their legs, birds use their ankle.

An integral part of the structure of the foot is the “intertarsal bend,” which is a fusion of the ankle bones of the calf and shin bone. It’s that larger “ball” of the leg that resembles a knee turned to the opposite direction. The whole foot structure is made for agile climbing.

Muscular System

Birds also have a wide range of muscles, usually about 175, that are going to control how the bird moves.  The largest muscles in birds are the breast muscles, which control the wings and makeup about 15 – 25% of a flighted bird’s body weight.

Urinary System

The urinary system is the bird’s waste removal system. The kidneys’ main function is to process and remove wastes from the blood.

Humans have bladders where urine is collected. Birds don’t have a bladder, instead, the waste extracted by the kidneys travels to the cloaca where they exit the body along with solid waste materials.

A bird’s high body temperature and level of activity mean that they need to conserve water. Because of this, their urinary system is designed to operate differently from humans.

The urinary systems of most animals produce urea which needs to be dissolved in large amounts of water to be excreted from the body.

Instead, birds produce uric acid that can be discharged as a thick paste along with their feces. This is the white chalky part of the bird’s droppings. A bird is able to urinate independently of defecating or passing feces, but most of the time, the bird will pass urine and feces at the same time.

Cockatiel Vision

As all the birds do, cockatiels have brilliant vision, in fact far superior to our own.

cockatiel anatomyA parrot’s eyes work without depending on each other. The retina is huge and bright. The fact that the eyes are positioned to the sides of the head means that the field of vision is wide.

A small blind spot forms to the very front and back of the head but this little “flaw” is replaced with a very flexible neck.

Humans have trichromatic vision. This means that we have three types of pin cells. Parrots have tetra or even pentachromatic vision, meaning that they have at least one pin cell type more than we do – and this means that they can see a whole color dimension that we can’t.

Whereas a human can see red, green and blue light, parrots see red, green, blue and ultraviolet light reflections. So, they can see UV colors. It is also said that they may see colors we aren’t even aware of.

Ultraviolet colors matter when choosing what to eat, especially when they live in the wild.

Cockatiels can detect 1,200 pictures in a second (Forbes, 2007), comparing to humans who can see about 20 pictures per second and even less in dim light.

All in all, the anatomy of the cockatiel is very interesting and also very different from that of mammals.

If you are going to be a bird owner, and if you are going to know everything there is to know about your pet bird, it is very important that you do all that you can to make sure you understand how your bird’s body works.

If you understand bird anatomy you will better understand your pet and how to handle him.


  1. Wow! This is indeed a knowledge enricher and I cannot deny the fact that I have learnt quite well through this post about bird anatomy. Seriously, learning about one’s pet always give a greater advantage as to know the vital organs that requires less handlings and pressure especially when playing with them to avoid injuring the bird pet. I have a friend who owns a parrot and I will gladly share this post with her. Thanks

  2. Hello Michael,

    I have a 22 year old Lutino Cockatiel named Mr. Kingie, he is a bit on the heavy side as you can tell just by looking at him. I will do a sternum check as you suggest, yes that works too.

    Funny thing is I have had other birds like love birds, cockatiels, budgies and they all have developed abdominal lumps and die. I used to feed these guys bread, corn, rice and basically processed food which I am almost positive caused the problems.

    Mr. Kingie was also fed the same food but is the lone survivor. He is a tough guy and is still going strong. We don’t feed him that crap anymore. I am a type 2 diabetic and now understand how nutrition is a very important factor in humans and anything living.

    Anyway back to your post, well written and great informative information. You are the birdman of birdmen.



    1. Thanks for stopping Jimmy and you are quite right about nutrition being the most important thing when it come to longevity in both birds and humans. 

      You must be doing something right if your cockatiel has made it to 22 years old. 

  3. My cockatiel just passed away on the 3rd of this month. There were no signs of his being sick until he started being constipated and poop stuck to his underside We dealt with it for a week with no avail as he got worse we took him to the vet where he died in his sleep. We were told he had an infection in his lung and a tumor and the doctor wanted to keep him overnight for antibiotics got a call in the early morning that he died in his sleep. We had no warning this was happening and the doctor said even if we had taken him in sooner he could not have saved him. We took excellent care of him and he was never sick until this one time and did not live through it. I do not understand and I miss him so much.

    1. Unfortunately, cockatiels can disguise when they are ill and often it is too late to treat them by the time we notice they are sick. It is always so sad to lose a pet, especially when they have been with you for years. No matter how well you look after them, sometimes it is just the way life chooses to play out.
      Thinking of you.

  4. Wonderful article on cockatiel anatomy, thank you! I have a pied 8 yr cockatiel that recently had wing and nails trim. He has been a very animated little guy and I love him very much.

    When I got him home after the trim, his behavior was weird. He kept falling off his perches and cage. I attributed this to maybe the nails were trimmed too short, I waited and watched for several days and no change.

    His eating habits were also affected, and he seemed like someone else’s bird, not mine. I took him to the vet after I saw that he wasn’t looking at his mirrored toys and doing the things he normally did. Also his foot “collapsed” instead of being strong to hold onto perch, and he wasn’t “monkeying over” to different areas in the cage. I identified him for sure as my bird. He was traumatized and suffered neurological damage, a stroke on left side and my bird cannot see out of either eye. I am beside myself.

    My question, is it possible that his eyesight may recover and that his foothold become stronger? Please advise, thank you:)

    1. Hi and sorry your cockatiel had to go through this. He was either highly traumatized or hurt by the people who did the job.
      I have never had to get my cockatiels nails done and I always do the wings myself to keep them calm. If you feel his nails are getting too long try buying a perch that is especially designed to keep his nails short and he won’t need to go through the clipping process. It almost looks like sandpaper on the perch.

      I am not sure he will recover if he had a stroke, but there is always hope and each bird handles trauma differently.

Leave a Reply

Your email address will not be published. Required fields are marked *

This website contains affiliate links, which means that commissions will be paid to the owners of this website if any purchases are made. This is at no extra cost to the buyer of the products.