Most of us know that we should be persuading our parrots to eat vegetables that are high in Vitamin A, such as sweet red peppers, carrot and broccoli. The leaves and roots of dandelion are also valuable sources of this vitamin.

A deficiency of Vitamin A or Vitamin B can result in a retained sheath on wing or tail feathers. Abnormal feathers, including those that are brittle and frayed, can also be caused by a mineral deficiency which can easily be avoided with the correct use of a mineral supplement. Parrots visiting clay licks might also be seeking minerals. In Peru, Blue-headed Macaws regularly visit mineral licks on the Rio Urubamba, in addition to visiting clay licks.

I believe that we should also offer our parrots grit – as a source of minerals and for digestive purposes. Even lories, that do not eat hard seeds, are known to consume grit in the wild. In one case known to me, a cockatoo fed on seed was found to have its gizzard compacted with unshelled pine nuts after death, almost certainly because it was not offered grit. This is used for grinding down hard foods. I suspect that macaws not offered grit swallow small particles of nut shells for the same purpose.

In Puerto Rico the fruit of the sierra palm (Prestoea montana) is a major food source of the Puerto Rico Amazon. We cannot acquire these fruits, but the fleshy berries of some trees, such as hawthorn, introduced to various parts of the world, make a good substitute that are greatly enjoyed by many parrot species. Even cultivated plants like roses have useful fruits. In Europe many breeders collect enough rosehips in the autumn to freeze them for use throughout the year.

It is worth mentioning that parrots native to different continents might be eating the same foods, because no country is free of introduced plant species, and parrots are highly adaptable and do not only feed from native trees. Many parrots in South America, including Military Macaws, feed on the seeds of the China tree, called Paradise tree in Spanish (Melia azerdarach), from Asia. Yellow-collared Macaws were feeding on these seeds.

On the island of Tobago I watched Orange-winged Amazons eating the contents of cocoa pods. They eat them in the green stage and when the beans are riper. This makes them deeply unpopular with the local people. After watching these birds I understood why many Amazon parrots relish green beans. Their natural food includes something that looks and tastes similar.

Strangely enough, the Purple-bellied Parrot (Triclaria malachitacea) shares with the spectacled bear a passion for feeding on bromeliads. We all know that bears love sweet things, and apparently bromeliads are full of sweet sugars. Eating bromeliads might be a common practice for canopy-dwelling parrots. I have watched Mitred Conures eating these flowers.

We associate parrots from South America with such habitats as rainforest, dry forest and seasonally flooded areas such as the Pantanal. Some parrots also occur in steppe habitat – that is, treeless plains covered in grasses. In Argentina, Patagonian Conures occur here, feeding on large thistles (Carduus mariana) and other weeds of temperate climates. Many keepers of this species could offer them their natural foods. The fruits of another common noxious plant, the blackberry, are eaten by parrots in the Andes, such as the Brown-breasted Conure (Pyrrhura calliptera), and can be offered to any parrots kept outdoors. Indoors, the juice will paint your walls red! Another common plant whose seeds are a highly valuable food for many parrots, is dock. It will be eaten in the green stage, especially by those birds rearing young, and the ripe seeds are eagerly consumed by parakeets and others.

For the long-term health and breeding success of our parrots we should take the trouble to learn about their diet in the wild. It is true that this is poorly known in many species, but reference to books such as Parrots of the World and volume 4 of Handbook of the Birds of the World will provide a lot of information.

It is well known that peanuts form an important part of the diet of Red-fronted Macaws. The natural vegetation has been replaced by crops throughout most of their range in Bolivia, thus they are forced to feed on peanuts and corn. Peanuts are legumes, not nuts. They are often unsafe for captive parrots, despite their inclusion in most parrot mixtures. Only unshelled high-grade nuts from health stores should be fed, and then sparingly. The risk of contracting aspergillosis from mould spores within the shell is a serious threat that has killed many parrots. Peanuts in shell found in parrot mixtures are often of poor quality, have been incorrectly stored, and explode with mould spores when opened, thus increasing the risk of aspergillosis.