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how does a parrot's digestive system work?

How Does A Parrot’s Digestive System Work?

Last Updated on January 28, 2024 by Carrie Stephens

Parrots don’t chew their food like mammals. As they lack teeth, their digestive system does the work.

All organs within the digestive system are compact and lightweight. Coupled with their efficient respiratory system, this enables parrots to remain airborne while digesting their meals.

Their digestive systems are adapted to pulverize food and move it through the gut. The crop is a muscular pouch that enables parrots to store food for later consumption.

Parrots won’t survive without energy from food, so their digestive systems are fast-moving.

How Parrots Digest Food

Parrots have an efficient way of digesting food that utilizes several organs. As parrots eat foods that are hard to digest, like seeds and nuts, the digestive process has evolved to cope.

Their digestive system gleans the most nutrients from food in the shortest possible time. This is key to survival from starvation and predators who may attack when a parrot is preoccupied with eating.

The digestive process and organs involved include:

Mouth And Tongue

Once a parrot has food in its mouth, the tongue pushes it into the digestive tract. The tongue sometimes holds worms, grubs, and other insects in place.

Parrots can’t chew their food, so they drop it into their throat. The pharynx, located between the mouth and esophagus, enables parrots to swallow complete pieces of food.

Esophagus

The esophagus (situated on the right of the neck) is what food moves down toward the parrot’s stomach. The extension of the neck also assists with swallowing.

Crop

The crop is a muscular pouch in the parrot’s neck, just above the sternum.

Parrots eat when they find food because they don’t know when their next meal will come. Food can’t be digested as fast as it’s consumed, so the crop allows parrots to store the surplus.

parrot digestive problems

Proventriculus

Once the food moves from the crop, it enters the proventriculus (glandular stomach).

Parrots have a two-chambered stomach. The proventriculus is a rod-shaped organ located between the esophagus and the gizzard.

The food is softened and broken down by gastric acid, mucus, and digestive fluids.

Gizzard

The gizzard is the second chamber of the stomach, located toward the rear of the body. It comprises muscles and a thick wall that grind food into smaller pieces.

Tough pieces of food move between the proventriculus and gizzard to break it down more efficiently.

Small Intestine

Once the food is broken down, it moves into the small intestine. The liver and pancreas absorb the nutrients, and the waste products are passed through to the further stages.

The small intestine is divided into three parts:

Duodenum

The duodenum is the first part of the small intestine, located between the stomach and jejunum. It breaks down partially digested food using enzymes and begins absorbing nutrients.

It produces hormones and receives secretions from the liver and pancreas. These fluids neutralize the acidity of chyme from the stomach, preventing digestive issues and damage to the gut lining.

Jejunum

The jejunum is the middle part of the small intestine. It’s nestled between the duodenum and the ileum and comprises 40% of the intestine.

The stomach contents move through the duodenum and enter the jejunum with the assistance of pancreatic enzymes and bile produced in the liver.

It absorbs nutrients, which enter the bloodstream for distribution to the organs.

Ileum

The ileum is the final section of the small intestines. It weighs 20-50% less than the jejunum, enabling a parrot to stay in the air while flying. The ileum accounts for 60% of the small intestine’s length.

Some fat, protein, and starch absorption occurs in the ileum, but it’s mainly a water, vitamin B12, and mineral absorption site.

Large Intestine

Leftover material travels through the large intestine, primarily to reabsorb water. Compared to a mammal’s large intestine, the large intestine’s role during the digestive process is mostly redundant.

Rectum

The rectum is a short tube at the end of the intestine that connects the intestines to the cloaca. Its function is to allow undigested food to pass into the cloaca.

Cloaca

The cloaca is a reproductive organ and storage facility for feces and urine.

Waste accumulates here before being released from the body. When the body is ready to release waste, it’s expelled through a sphincter at the base of the cloaca.

Parrot Digestive Problems

The most common parrot digestive problems include:

Avian Gastric Yeast

Avian gastric yeast is caused by a fungus (Macrorhabdus sp) that can affect a parrot’s crop, proventriculus, and ventriculus.

As described by the MSD Veterinary Manual, avian gastric yeast colonizes the digestive tract of birds. Parrots with vulnerable immune systems are most affected.

The symptoms of avian gastric yeast include:

  • Chronic weight loss.
  • Regurgitation.
  • Lethargy.
  • Diarrhea.
  • Undigested seeds or pellets in the feces.

A vet will examine the parrot’s droppings under a microscope. If organisms are present in the parrot’s waste, avian gastric yeast can be treated with Amphotericin B.

The death rate in affected parrots is 10-80%, with stronger yeast strains more likely to be fatal. If it recovers, relapses are possible. Close monitoring is required for the rest of the parrot’s life.

Parrots can shed the organisms in their droppings. Therefore, the parrot’s poop (and old food) must be removed from the cage to prevent reinfection.

The infection can be transmitted between parrots. If you own two or more parrots, avoid spreading the infection by quarantining the infected bird.

Candidiasis

Thrush is an environmental fungus caused by Candida albicans yeast, usually found in small amounts in the parrot’s digestive tract. The symptoms include:

  • Regurgitation of food.
  • Lack of appetite.
  • A swollen, mucus-filled crop.
  • White spots in the mouth.

Candidiasis is more common in young, unweaned parrots on antibiotics because they have undeveloped immune systems and are more susceptible to illnesses.

Adult parrots with malnutrition or on antibiotics are most vulnerable. It can spread from adult to juvenile parrots or through a contaminated environment. Candidiasis affects a parrot’s:

  • Crop.
  • Stomach.
  • Intestines.
  • Skin.
  • Respiratory tract.
  • Central nervous system.

A vet will recommend a reduced feeding program to empty the crop and antifungals, like nystatin.

Proventricular Dilatation Disease (PDD)

Also known as macaw wasting disease, this condition affects the nervous and digestive systems.

It stretches the stomach and prevents the normal function of the muscles required for digestion. The damaged nervous system stops nutrients from being absorbed and digested.

Proventricular dilatation disease is caused by an avian-bornavirus that occurs after exposure to the feces of infected parrots, usually when sharing a cage. The signs of PDD include:

  • An initial increase in appetite.
  • Chronic weight loss.
  • Undigested food in the feces.
  • Smelly stools.
  • Regurgitation.
  • Convulsions.
  • Head tremors.
  • Weakness.
  • Incoordination.
  • Blindness.
  • Difficulty perching.
  • Leg paralysis.

Proventricular dilatation disease is incurable, but it can be controlled with palliative care. The cage must be disinfected to remove the infection, and ventilation can reduce transmission rates.

Pacheco’s Disease

The psittacine herpes virus causes Pacheco’s disease, leading to liver inflammation. This leads to:

  • Lethargy.
  • Diarrhea.
  • Ruffled feathers.
  • Sinusitis.
  • Anorexia.
  • Conjunctivitis (red eye).
  • Neck, wings, and leg tremors.
  • Discolored urine and feces.

The disease is contagious and transmitted through contaminated feces and nasal discharge. It can also spread through contact with sick birds and contaminated food and water.

Pacheco’s disease can lead to pink, cauliflower-like growths called papillomas. Papillomas grow in the mouth and digestive tracts, causing wheezing, open-mouthed breathing, and difficulty swallowing. 

Papillomas that grow in the digestive system can cause vomiting and appetite loss. They sometimes protrude from the vent and can be observed when the parrot strains while defecating.

The surgical removal of papillomas is required. Growths may recur, so palliative treatment is needed.

Gastrointestinal Parasites

Intestinal parasites in parrots include:

Giardiasis

Giardiasis (bird giardia) occurs when microscopic single-celled parasites called protozoa attach themselves to the intestines of parrots.

They’re common in cockatiels and budgerigars but affect most species. Adult parrots are often carriers. Transmission occurs through infected water or consuming contaminated feces.

The symptoms of giardiasis include:

  • Diarrhea.
  • Malnutrition.
  • Inability to absorb nutrients.
  • Itching, which causes the parrot to pull or dig at its feathers.
  • Abnormally large droppings.
  • Thinness.
  • Poor feathers.
  • Excessive crying.

Oral medications, like metronidazole and ronidazole, are used to treat giardiasis.

how parrots feed and digest food

Trichomoniasis

Trichomoniasis (frounce or canker) is a protozoan infection that causes whiteish-yellow lesions on the mouth and throat lining, crop, and esophagus.

While the lesions aren’t always visible, infected parrots experience increased salivation and regurgitation. The disease is transmitted through direct contact or contaminated food and water.

Treatment involves taking antibiotics, like metronidazole, twice daily for 5-7 days.

Roundworms

Roundworm is transmitted when a parrot eats roundworm eggs (larvae). Affected parrots show signs of weakness and emaciation, which can lead to death if roundworms block the intestines.

A vet will examine the feces for parasitic eggs and prescribe ivermectin, fenbendazole, or piperazine. If roundworms obstruct the intestines, surgical removal may be necessary.

Tapeworms

Parrots become infected by eating food contaminated with tapeworm eggs. Once they reach the bowels, the tapeworms grow a ribbon-like body with eggs that enter the digestive system.

The eggs exit the body through the parrot’s droppings, and insects consume the eggs. In turn, the insects are eaten by parrots, continuing the cycle. The symptoms of tapeworms include:

  • Weight loss.
  • Quietness.
  • Loose droppings.
  • Nutritional deficiencies.
  • Change in appearance.
  • Loss of appetite.

A vet will administer praziquantel or epsiprantel for tapeworms. Also, the cage will need deep cleaning.