Are Natural Diets Nutritional?

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Q: There is a lot of controversy over what is the proper diet for different types of parrots. You have studied many different birds in their natural habitats, and I am sure that you know that they seek out specific foods. It seems to me that it would be a simple matter to analyze their natural diets and put the controversy to rest. Why has this not been done?

A: In many instances, this has been done. Unfortunately, in most cases, the information gained is of limited value unless the species being studied is a “mono-eater” (that is, a living thing that exists mainly or exclusively on one type of food). An example of this in parrots would be the red-bellied macaw. The majority of parrots, however, exist on a varied diet.

Determining the nutritional content of their natural foods is the easy part. The problem comes when you wish to determine what percentages of their daily food intake are made up of each of these various natural foods. This is something that is impossible to learn from observation.

As we all know, despite their ability, most parrots do not choose to be efficient eaters. Unlike most living things, parrots do not swallow everything that they put into their mouths. We have all seen parrots “pretend” to eat a particular food, only to find out upon close examination that they did nothing more than take it out of their dish and pulverize it onto the floor. How much they choose to swallow, of any given food in any given circumstance, depends on many variables.

This is further complicated by the fact that they are very intelligent and, therefore, vary drastically from one individual to the next as to their personal likes and dislikes. The only way to acquire this type of information accurately is to go out into the jungle and kill a group of birds. It is not good enough to kill just one or two. A reasonable sampling would have to be “harvested” in order to yield relevant statistics. A large sampling would be needed to reduce the influence on the statistics of birds whose tastes were not within the norm.

Of course, a horrible act such as this would be completely out of the question. In the past, actions such as this have been done in the name of science. Many people do not realize that every mention of “crop contents examined” in reference books concerns birds that were killed in order to make this examination.

The next problem is seasonal dietary change. As the year progresses, the food that is available changes. The nutritional value of what the birds are eating during one part of the year is completely different than what is available six months later. Some natural crops are available in large quantities for a short period of time, while others are in short but continual supply.

We must also consider the fact that the availability of crops can vary drastically from one year to the next. Years that are much wetter or drier than normal will have foods available in much different ratios than in “normal” years. In many of the more temperate zones that parrots inhabit, there is another yearly variable. The availability of some foods will vary depending on the amount of cool weather the crop-bearing trees endure during the mild winters. What if we choose to do our study in an off year? The birds might be forced to live on a deficient diet for that year yet show no outward symptoms of a deficiency.

This brings us to the most important point of all. Just because they are doing it “naturally” does not make it good. There are populations of birds and animals in habitats all over the world that survive and reproduce on grossly deficient diets. All a pair of living things has to do in order to maintain a population is survive long enough to produce two offspring that, in turn, survive long enough to reproduce. Living a long, healthy life has nothing to do with this.

Quite a few years ago, I was asked to go to Bangladesh to oversee the health and care of over 10,000 ringnecked parakeets that were to be captured for export. These birds had become major pests in the agricultural areas where the country’s rice was grown. This is a country where there are people starving from the lack of food, and they needed to reduce the wild ringneck population. The decision was made to export rather than exterminate. The particular population that they wished to control were living almost exclusively on “paddy” rice. This was not a case where due to habitat destruction the birds were forced to raid agricultural crops. These birds had expanded from their historical range in order to take advantage of this available bounty. They were so prevalent in the rice fields that young boys with fishing cast nets were used to capture them.

During the time period between capture and export, approximately 150 birds out of the 10,100 that were collected died. About half of these died from injuries that were sustained during capture or transport. Another 25 percent of the 150 died because they refused to eat. The remainder succumbed to miscellaneous problems. I did a gross necropsy on all 150 of them. I was shocked to find that approximately 70 percent of these had visceral gout. This is a nutritional disease where white uric acid crystals are deposited on the internal organs. This percentage also held up when I only considered those birds that I believed had died from injuries.

From this experience, I believe that it is fair to say that a large percentage of the Indian ringneck population in that part of Bangladesh is dying of a lethal nutritional disease. Despite this, the birds were able to live long enough to not only replace themselves, but to increase their overall population to “pest” proportions. After the birds cleared quarantine in the United States, some of the younger birds were endoscoped in order to determine if they were young males or females. A large percentage of this group, as well, showed the symptoms of this disease. After one year of good nutritional support, the birds were re-examined and appeared to be cleansed of the problem.