By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc (Avian health)
Knowledge regarding the nutritional requirements of birds has increased dramatically over the last ten years. In the past caged birds were given a bowl of seed, fresh water, perhaps a cuttle fish bone, and if they were lucky the occasional piece of green food or fruit. We now know that dry seed diets fail to provide a complete diet leading to a shortened life expectancy and increased health problems that in the past were regarded as normal.
Basically dry seed diets are too high in fat and quite low in protein. Birds eat to satisfy their protein requirements, in the process taking in excess fat and often becoming obese. Dry seed diets also lack many essential nutrients. Vitamins such as vitamin A, B, D, E and K are all low in seed as are certain amino acids such as methionine, choline and tryptophan. The mineral content is also low particularly in regard to calcium and iodine. The level of calcium relative to phosphorous in the diet should be in the ratio of approximately 2.2 to 1, while in some seeds this ratio is 1 to 4. Low calcium levels lead to osteoporosis and reproductive problems while iodine is essential for many metabolic processes. Low dietary iodine leads to an enlargement of the thyroid gland called goiter. Interestingly pathologists report that up to 70% of all autopsied caged birds have abnormal thyroid glands.
Any adjustment to the diet that enables it to mimic more closely the wild diet contributes to the overall health of the bird. In one study of Rosellas in NSW up to 86 different varieties of vegetation were eaten in a single day.
Caged birds should be provided with a variety of fruit and greens. Essentially any fruit or vegetable that you would eat is fine for your birds (except onions, rhubarb and avocado). Particular favorites are carrot, corn on the cob, apple, silver-beet, capsicum and spinach, but also try sprouts, pomegranate, strawberries, pear, broccoli and oranges. Also many “weeds” are excellent foods. Milk thistle and dandelion (which is particularly rich in calcium and vitamin A) are excellent food sources, while the ripe and half ripe seeds on many grasses such as panic veldt grass, nut-grass, and clover are packed in vitamins and minerals. Many commercially available pellets, such as Passwells, offer another excellent way of providing a more balanced diet.
It can be hard to convert a “seed addict” to a healthier diet but there are several tricks. Most birds don’t feed at night because it is dark so they awake hungry and often feed first thing. Removing the seed in the evening and only providing fruit and veggies or pellets in the morning for the first few hours often gets them started. Alternatively mixing the new food with their seed, hand feeding , or only providing seed for say, 15 minutes twice a day while leaving the fruit and greens or pellets always available may do the trick.
For birds that consistently refuse to eat a more balanced, nutritious diet a water supplement is available that specifically contains the vitamins, minerals and amino acids known to be lacking in a dry seed diet called “Nutrivet”. It is an excellent way of supplying these nutrients while continuing to broaden their diet.