Abstract
Parrots in their natural habitat feed to meet their energy requirements. The captive bird becomes obese by overeating simply because the wrong diet is offered or, to relieve boredom, it eats compulsively. Unfortunately, there is a lack of basic knowledge of the requirements of the psittacines' diet. Amazons in the wild feed at all levels. There are the tree top feeders, those that find food on or in the ground and those that feed in between on scrub and bush. Many seek fruit in order to eat the kernel, berries, pollen or nectar together with buds and shoots and whatever insects or grubs are present, so a great variety of fresh food is sought.Where the land has been cultivated, the parrot has learned to feed on crops, but cultivated land provides its main source of food only where natural and more profitable habitat has been completely destroyed.
This occurs mainly on small islands where the parrot has, over many years, adapted to a specialized diet. In some species this is very limited and cultivation, in the long term, must interfere with natural selection, or the survival of the fittest. The benefits of providing a good balanced diet are obvious. If the ratio of energy to protein are correct, and the amino acid profile and mineral and vitamin levels are suitable, birds do not become obese. Such well fed birds look good, they have good plumage, good disease resistance and spend a reasonable part of the day in normal feeding activities; the rest, hopefully, preparing for breeding, and will live to a ripe old age. Consideration given to providing the right foods is vital in any captive breeding project. More information is needed to improve the understanding in some of these areas. For the moment, much has to be based on extrapolated information. Deficiencies occur when birds are fed a restricted diet. They then often develop fads and further restrict their own diet. Pet psittacines are often kept indoors and denied access to natural light. This causes vitamin 03 deficiency unless additional dietary 03 is given.
Many years ago we decided to change the sunflower based diet that we were feeding our parrots. I had been able to do some field studies and became aware of the types of bulky food consumed by Amazon parrots. We decided to undertake feed trials, so groups of birds were set up. The group fed mixed pulses, fruit and vegetables with some added calcium, not only looked magnificent hut produced far more fertile eggs and vibrant chicks.
The legumes and grains are soaked for 24 hours and the water must he changed several times, as some of the nutrients will enter the solution and encourage bacterial growth. For the same reason, seeds should he rinsed and drained before feeding.
To encourage sprouting, legumes and seeds are trayed for a further 24 hours. The depth of trayed legumes and seeds should not he more than % of an inch. They are washed and drained a further couple of times during this period.
Sprouting of legumes and pulses raises the digestibility. Some of the relatively indigestible carbohydrates such as starch are converted into more digestible dextrins, etc., and even into protein as the sprout grows. The vitamin levels also rise slightly, especially vitamin C. although not enough to be relied on as a major source.
Germination also makes the seeds of the legumes safer by reducing some of the toxic or anti-nutritive factors present in them. Soya beans, for instance, contain a trypein inhibitor which reduces the digestion of proteins. The simple act of soaking also makes it easier for the birds to break up the seed for digestion.
During warm weather, sprouted seed components tend to spoil. Care must be taken to replace spoiled food. If left, it will encourage the growth of aspergillus. The climate will influence the nature of the diet fed to captive parrots. Most Amazons relish green food we favor-alfalfa, landcress, dandelion and watercress, together with green shoots from· suitable non poisonous trees. Not only are these materials nutritious hut provide an interest for the captive parrot.
There are several pelleted diets now being marketed. We have tried to use some. However, our charges did not take to them. I felt sympathy at their reluctance to accept them. Most are well researched and certainly better on purely nutritional values than many diets fed to parrots. But I feel they should be supplemented with some fresh fruits and vegetables.
It will be difficult to convince European a viculturists that a natural type diet can be superceded by an artificial one.
Many birds eat nothing but dry seed simply because it is more convenient and less time consuming for the owner, so there is justification for converting the birds to a pelleted diet. Often it is harder for the owner to convert the seed junkie to a more suitable diet simply because of the owner's concern that the bird might fast completely. So tact on the keeper's part will overcome this. Complete withdrawal of food, except fruit, for periods will help, then offering food three to four times a day for periods of 30 minutes or so will often persuade the reluctant feeder to try the new experience.
Vitamins and minerals necessary to the parrot are Vitamin A, Calcium and Vitamin D3, Vitamin E, and B Vitamins.
Vitamin A is the most common vitamin deficiency seen in parrots.The supply of this vitamin relies on the bird converting B carotene available in fruit and vegetables into Vitamin A. Some supplementation is advisable.
Calcium and Vitamin D3 is a major problem to birds on a seed only diet. The first signs of deficiency are often soft shelled eggs and egg binding. Chicks will also have soft bone structure. Calcium absorption requires the presence of Vitamin D3, so parrots kept indoors are most at risk and require a reliable supplement. Fish liver oil is not recommended because of its instability.
Vitamin E is needed for good hatchability and is found in green plant food, whole grain cereals, soya beans, eggs and vegetables. Great care must be taken not...