Your BIRDS Anatomy
                    and how it's Digestive Systems works



  • A Bird's skin is not so obvious as it is covered with feathers.

  • If you part the feathers you can see the skin, which is virtually transparent

  • You can see the outline of the ribcage and the muscular system below the skin

  • Modified skin cells help make up the beak, cere, claws and the scales on his feet and legs.


  • Did you know that some birds bones are hollow and made up of a honeycomb of bone tissue.

  • This is what makes them lighter and allows them to fly.

  • This also makes them more susceptible to damage and breakage

  • For this reason you must always handle your birds carefully.

  • Another adaptation for flight is that the bones of the bird's wing (which corresponds to our arm
    and hand bones) are fused together for the greater strength they need to flap.

  • Birds also have air sacs in some of their bones  (called pneumatic bones) - throughout their bodies.

    • These air sacs help lighten the bird's body and also help to cool him more efficiently.

    • Birds cannot perspire as mammals do because they have no sweat glands.

    • So this is one of the ways to help keep them cool.

  • Parrots have ten neck vertebrae compared to 7 in a human and lots of other mammals
    (even a giraffe only has 7!)

  • This makes the Parrot's neck more mobile (have you seen a Parrot do an "Exorcist impression"
    i.e. turn it's head almost 180degrees)

    • This is important in the Wild for spotting predators and food

    • And lethal in captivity when trying to catch a Parrot that doesn't want to be caught.

      • It can twist it's head right round and give you a nasty nip!!

  • During the Breeding Season, the hen's bones become more dense, as they store calcium needed to create egg shells.

  • A female's skeleton can weigh up to 20% more than normal during the Breeding Season than during the rest of the year.


  • Your bird's respiratory system is a highly efficient system.

  • It works in a very different way to yours.


A Bird breathes in a unique way - like no other animal.

Its actual lungs are relatively small in ratio to its size but it's total respiratory system is twice as big as an equivalent-sized animal.

In addition to its lungs, it has 12 air sacs distributed throughout it's body, wing and leg bones.
These air sacs keep the lungs constantly supplied with oxygen-rich air. So, it's a bit like an inflated balloon made up of separate air pockets!!

A birds' leg and wing bones are honeycombed - the "spaces" in the Honeycomb are also filled with oxygen rich air.
This helps to keep the birds body-weight light and enables them to to fly long distances at great heights and not get out of breath or suffer from Altitude sickness (lack of oxygen) as a human could.

This constant supply of oxygenated blood is also used by its vital organs and to convert carbohydrates into vital energy.

When the bird breathes in the air goes into the large lower air sacs and the lungs. When it breathes out the air sacs empty but the lungs retain a steady 10% of air at all times.

To back up the vastly bigger respiratory system - birds have a much larger heart. The smaller the bird the bigger its heart in ratio to it's size - think of the tiny humming bird and the energy it expends to flap its wings at the rate it does to hover.

If a birds respiratory system is effected in any way by : air sac mites, aspergillosis, aerosols or lethal fumes off Teflon etc., everything comes to a halt and it can seriously debilitate or kill even the bird, as the toxins invade nearly all of its body spaces as opposed to just the 2 lungs of a mammal ! Evil or Very Mad

- CLEAN AIR is essential to BIRDS more so than any other animal or mammal - this is why you should never spray aerosols in the same room as your bird or have a dusty or smoky atmosphere.

Vets' Note: We are all aware of the effects of smoking in humans but as Birdbrain pointed out, birds breathe much more effectively which means sadly, they breathe smoke in too damaging their delicate lungs. It not just birds that are affected but dogs and cats too so if you do smoke then please remember they have no choice but to breathe in your smoke. Sad

The actual process of Breathing

  • Air enters the system through your bird's nostrils (nares)

  • It passes through it's sinuses and into it's throat

  • As it does so, the air is filtered through the Choana,

    • this is a slit that can be easily seen in the roof of many birds' mouths.

  • The Choana also helps to clean and warm the air b4 it goes further into the respiratory system.

  • After the air passes the Choana

    • It flows through the Larynx and Trachea

    • Then past the Syrinx (voice box)

  • Your bird doesn't have vocal cords as a human does

  • The vibrations of the Syrinx membrane are what allows our birds to make their sounds.

  • So, far it is similar to the way we breathe however now the difference begins:

    • As the air continues its journey past the syrinx and into the bronchi (your birds' lungs)

    • The Bronchi DON'T expand and contract to bring the air in

    • This is partly due to the fact that birds don't have a diaphragm as we do.

    • Instead, the bird's body wall expands and contracts

      • A bit like Fireplace Bellows

    • This action brings air into the air sacs (see note above - under Skeletal System)

    • This Bellows action also moves air in and out of the lungs.

  • This system is very efficient at exchanging gases in the system

    • 2 complete breaths are required to do the same work that a single breath does in a
      human other mammals.

  • This is why you may have noticed that your bird seems to be breath quickly esp. compared
    to us humans

  • This is also why a bird cannot cope with noxious atmospheres, sprays etc.,

    • It "Breaths" twice as much in becos it breaths twice as often.


  • Along with the respiratory system

    • Your bird's Cardiovascular (heart and blood circulation) system keeps oxygen and other nutrients moving throughout the bird's body.

  • The Blood Circulatory path in the bird's body differs from yours:

    • In the bird the blood flows from its legs; reproductive system and lower intestines then
      passes through the kidneys on its way back to the general circulatory system.


  • Has 4 Chambers

  • With 2 Atria and 2 Ventricles, just the same as we do

  • However, here is the difference:

    • A humans heart beats at approx 72 b.p.m. (beats per minute)

    • A birds Heart beats between 340 - 600 b.p.m.


  • Your bird's body is an energy efficient machine which requires a constant supply of good quality
    food to keep it running at optimum levels.

  • This is where the digestive system comes in:

    • It provides the "fuel" that helps maintain the Bird's body temperature.

    • Without food the bird can cool down - it needs food to keep warm

      • esp. chicks that can chill quickly without a constant supply of food and then die.

    • A bird's natural body temperature is higher than ours and they feel warm to the touch.

  • A bird's Digestive system begins with it's Beak.

    • The size and shape of a bird's beak depends on his breed and his food-gathering needs

      • Compare the sharp, pointed beak of an Eagle with the elongated bill of a Hummingbird to the hooked beak of your Parrot.

    • Notice the underside of your bird's upper Beak, if you can

      • It has tiny ridges in it that help a Parrot to hold and crack seeds and nuts more efficiently.

  • A Parrot's mouth works a little differently than ours and other mammals:

    •  Parrots don't produce saliva to help break down and move their food around as we do.

    • Also, their Taste Buds are contained in the roof of their mouths, unlike ours which are
      on our tongues.

    • Because they have only a few taste buds, experts seem to think that a Parrot's sense of taste is poorly developed. (open to debate)

  • After the food leaves your bird's mouth

    • It travels down the oesophagus, where it is moistened.

    • The food then travels to the Crop

    • Here it is moistened further

    • It is then passed in small portions down to the Bird's stomach.

  • After the food leaves the crop

    • It travels thru the Proventriculus, where digestive juices are added

    • Then into the Gizzard, where the food is broken down into even smaller pieces.

    • Then on into the Small Intestine where nutrients are absorbed into the blood-stream.

  • Anything that is left over i.e. indigestible particles of food

    • This carries on thru the Large intestine and into the Cloaca

      • (which is a common chamber that   collects waste products b4 they leave the bird's
        body thru it's vent in the form of a dropping.

  • The whole process from taking Food into the mouth, going thru the Digestive process and being
    passed out as a Dropping usually takes less than an hour.

  • This is why your Bird does lots of small droppings throughout the Day.

  • Along with the solid part of your Bird's droppings you will also find urine in the form of
    semi-solid urates:

  • Your bird's kidneys create urine which is then transported thru Ureters to the Cloaca for excretion.

  • These are the white/off-white parts of the birds droppings.

  • The colour of these Urates can tell you a lot about a bird's Health:

    • Yellow, green or blood-streaked - need investigation from your Avian Vet.

  • Birds do not have a bladder or a urethra as we humans do - everything passes thru the Vent.

  • Birds pass droppings approx every 15 mins!!


  • A Bird's Nervous System is very similar to ours.

  • Both N, Systems are made-up of:

    • The Brain

    • The Spinal Cord

    • Countless nerves throughout the body that transmit messages to and from the Brain


  • Feathers - birds are the only "animals" that have feathers!

  • They enable a bird to fly

  • They keep a bird warm ( when they fluff them out, warm air from their bodies is trapped)

  • They attract attention from prospective mate esp. brightly coloured male birds.

  • Feathers grow from follicles that are arranged in rows known as Pterylae.

  • A feather is a fantastic creation:

    • The base of the feather shaft, which fits into the birds skin, is called a Quill.

    • It is light and hollow (and used to be used to write with in the 19th Century+/-)

    • Very tough and resilient.

    • The upper part of the feather shaft is called the Rachis.

    • From it's branch, the Barbs and Barbules (smaller barbs) make up most of the feather

    • They have small hooks on them that enable the diff. parts of the feather to interlock with
      each other - like velcro.

Birds have several different types of feathers on their Bodies.


    • These are the colourful outer feathers on a bird's body and wings.


    • These are an under coating of feathers that help keep the bird warm


    • Found round the bird's Beak, Nares and eyelids



      • The large wing feathers that push a bird forward during flight.

      • These are the ones that are clipped if a Bird is WING CLIPPED.


      • These are the ones found on the Inner Wing and help support the bird in Flight

      • Both Primary and Secondary can operate independently of each other


      • These assist in flight by acting as a brake and a rudder to aid steering.


  • Healthy Birds spend a great deal of time fluffing and preening their feathers.


    • It is normal to see a bird picking at the base of its tail on the Top Side

    • This is how the bird removes oil from the preen gland and then spreads it onto its feathers

    • This oil also helps prevent skin conditions/infections

    • It also helps to waterproof the feathers.


    • Sometimes you will see white lines or small holes appearing on the birds large feathers
      on their Wings and/or Tails.

    • These lines/holes/imperfections are referred to as Stress Bars/Lines

    • They result from the bird being under stress (for any one of multiple reasons) when the feathers were developing

These must not be ignored and you must try and find out what the problem is/has been and try to rectify it.

  • It may be Diet-related

  • Deficiencies

  • Housing

  • Change of surroundings

  • Boredom

  • unhappy

  • incompatible mate or neighbours

  • Being bullied

  • lack of or change of Routine

  • low grade infection  etc., etc.,


  • Not usually anything to worry about

  • Some Theories are:

    • Excessive Beta Carotene

    • Old age

    • Plucked Feathers growing back Red (most probable)

Some people think it may be:

  • Medical problems suggested are :

    • PBFDS

    • Liver problems

    • Kidney dysfunction

    • systemic disease


  • They have well-developed sight

  • Birds can see detail and can discern colours

  • Be aware of this when selecting your birds Cage, Accessories, Toys and Food Dishes

  • Birds can react in different ways to colours esp. if they have become used to one colour Feed dish,  and then you change it

  • Because their eyes are located on the sides of their heads

  • Most birds rely on monocular vision

    • This means they use each eye independent of the other

  • If a bird really wants to study an object you will often see it tilt his head to one side to examine the object with just one eye.

  • Birds aren't really able to move their eyes around very much and have to move their heads to
    see things.

  • They compensate by having a very mobile neck - which can turn their heads 180degrees.

  • Like Cats and Dogs Birds have 3rd eyelids called "Nicitating membranes

    • You will sometime see this eyelid flick across the eye.

    • It's purpose is to help keep the eyeball moist and clean

    • If you see this membrane for more than a brief second - be aware

    • You may nee to see your Avian Vet to make sure all is well.

    Birds don't have eyelashes

    • In their place are small feathers called "Semiplumes"

      • these help keep dirt and dust out of the Bird's eyeball.


  • A Bird's ears are largish holes in the side of a bird's head and are covered by feathers

  • A. Greys have about the same ability to distinguish sound waves

  • and determine the location of sound in a similar way as people do

  • Birds seem to be less sensitive to Higher and Lower pitches than humans.


  • Birds seem to have poorly developed sense of Smell and Taste.

  • Because smells often dissipate quickly in the air  (where flying birds spend a lot of time)

  • Birds have fewer Taste buds than we humans

  • A bird's Taste buds are located in the roof of their mouths

  • Not on their tongues as in humans.


  • This is well developed in parrots

  • Parrots use their feet and mouths to touch and test their surroundings.

  • Young birds, in particular, see to test everything with their beaks to check what it is and if it's safe.

  • Parrots feet are very tactile

  • 2 of it's feet point forward

  • 2 toes face backwards

  • this is called Zygodactyl and allows a Parrot to hold food or Toys etc., in its feet.

  • It also allows a Parrot to climb around easily.


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