Captive or pet birds generally prefer their rearing diet, at least for the first 5-6 weeks so correct early nutrition is extremely important. Add as great a variety as possible after fledging to prevent food 'fads' from developing.

Birds have a particularly high metabolic rate (as compared to other animals). They have made some special adaptations to enhance this. Firstly their jaw has developed into a beak for de-husking and of course they don't have teeth which saves chewing food and adding muscle weight to a 'chewing' jaw.

Food passes into the crop which is a storage and soaking area. Crop milk, produced by a few specie such as the pigeons and doves, is actually the lining of the crop which sloughs off and is fed to their young for the first 3 or 4 days. and is not a 'milk' as such. Young budgerigars are fed on fluid from one of the hen's stomach chambers and is particularly high in protein. Food passes from the crop into the stomach where digestion begins. The first area is the proventriculus which secretes digestive aids and this continues as the food passes into the ventriculus (commonly called the gizzard). Food is broken down further here by the ingestion of grit. Food then passes into the small intestine and most foods then are completely broken down and absorbed through the intestinal wall. The large intestine's function is mainly water reabsorption. Food transit time for the budgerigars and finches is approx. 3-6 hours. Birds have a low requirement for water, this being a weight lowering factor. Urine and faeces is voided together via the cloaca where the ureters and large intestine exit.

In the wild, birds generally forage twice a day — in the early morning and the early evening, so it is best to feed them twice a day. Check what a bird is actually eating, rather than what they are offered. They often ignore some food, hoping to be offered “treats”. Birds are often 'conservative’ eaters and shun anything unfamiliar. They need to see a new food many times before they will try it. Acceptance is improved if foods are served in 'mixes' e.g. cooked multi-grain mix or a fresh food mix of chopped vegetables, greens, cooked beans, fruit.

Food intake may diminish if there is a rise in temperature above that of which the bird can cope via the usual respiratory tract and skin evaporation. Fresh water is essential (a Budgerigar consumes 3-5 mls daily. Canaries are sensitive to lack of water). Inadequate water intake makes droppings appear dark green.

The primary energy source of seed-eating birds is starch although fat is important for newly hatched chicks Birds are fat sensitive and will regulate their metabolism to cope. An excessive fat intake can cause diarrhea and may make calcium and iron unavailable to the bird.

Essential Fatty Acids are essential for birds, deficiencies in chicks will retard growth, the skin becoming rough and flakey and increasingly permeable this forcing the bird to increase its water uptake. Always provide a variety of seeds including linseed which is a good source of linoleic acid.

Protein requirements rise during chick development, moulting, reproduction during egg laying and 'crop milk'. Otherwise feed should contain 10% – 16% protein. A teaspoon of complete protein daily would be enough for a medium size parrot. White millet and rapeseed contain high levels of the amino acids necessary for feather development.

Budgerigars always seem to consume a lot and they do — approx. 500–1000 seeds a day!

Food sources vary in their content of “complete” protein, which contains all the essential amino acids. Essential amino acids are those which the bird cannot manufacture itself from other ingredients, so must be provided in the food. Corn protein is “incomplete” as it lacks many of the essential amino acids, whereas eggs, chicken, fish, dairy products and other animal proteins are high quality protein foods. Other good protein sources are garbanzo beans, lentils, soy beans, pinto beans, red kidney beans, split peas and white kidney beans. If beans are fed with whole grains, animal protein is not needed — otherwise provide some animal protein. Parrots are often claimed to be lactose intolerant, but can digest low to moderate amounts of dairy products. If the droppings are loose and watery, reduce the amount given.

Calcium and phosphorus are essential. Imbalances show as rickets (when fed only high fat/oil seeds), some cases of soft shells, some cases of egg binding, chronic deficiencies in appetite loss, feather chewing, weakness and lethargy. Sources: — refer Nutrition, provide shell sand, limestone grit, and cuttlefish.

Iodine — deficiency results in goiter, respiratory difficulty, regurgitation of food, lack of activity. Cod liver oil contains high levels of iodine.

Manganese — deficiency in poultry results in slipped tendon. Seeds are naturally low in this mineral.

Zinc — deficiencies — poor wound healing, skin problems, reproductive capability loss, excess can inhibit growth, cause anemia. Take care with zinc toxicity due to zinc oxide ingestion from newly galvanised aviary netting.

Vitamin A — most seeds are deficient — can be caused by overfeeding sunflower seeds. Supplement with a little cod-liver oil, dandelion etc. Generally other vitamin sources are adequate if a diverse diet is given.

Nuts are high in both fat and protein and also contain minerals — perhaps the best snack food for birds.

Fruits provide carbohydrates and may help to maintain the acid / alkaline balance, but is generally low in protein, vitamins and minerals. If too much is eaten, the bird may neglect more nutritious foods, so should be limited to no more than 10% of the diet.

Non-oily seeds and grains are nutritious. These include millet, canary seed, buckwheat, oats, rye, barley, wheat, quinoa, spelt, kamut, amaranth and rise, which can be fed soaked, sprouted or cooked. Some can be fed raw. Sunflower, safflower and peanuts are too high in fat and low in calcium, vitamins and protein.

Foods high in fat, sugar and salt 'pervert' the appetite. Highly processed foods such as pellets should also be restricted. At least 50% of the diet should be in fresh, live, raw food.

Fresh vegetables and leafy greens — particularly dark green and yellow are important.