MY THOUGHTS ON THE WILD-CAUGHT WHITE-RUMPED SHAMA IN CAPTIVITY - PART II

THOUGHTS ON FEEDING THE CAPTIVE WHITE-RUMPED SHAMA

Facultative insectivorous wild birds of temperate regions will switch between feeding on insects and other food sources depending on seasonal availabilities. Unlike these birds, the food sources of the tropical wild shama is not affected by climatic fluctuations in the same way. Hence, it has evolved to be a specialist feeder that feeds only on insects and small invertebrates that are found in its habitat throughout the year. When taken into captivity, the specialist feeder will not willingly feed on unfamiliar food items (such as dry pellets), even when forced by extreme hunger. This feeding instinct of the newly wild-caught shama that is so well tailored to its natural habitat will have to be altered by its keeper if it is to survive in captivity. Its digestive system that is so well adapted to its natural food sources will have to be adjusted to accommodate and utilize the captive diet. It has also to be conditioned to eat sufficiently from the captive diet that must also provide adequately in order for it to thrive.

Although it is not difficult these days for the keeper to provide a captive diet that is made up of commercially farmed insects, this alone will not be adequate. Commercially farmed insects are nutritionally inferior in comparison to the natural prey items found in the wild. The lack of variety in commercially farmed insects will also render such a diet to be nutritionally inadequate. The commonly available farmed crickets and mealworms are high in fats and chitin and lacking in many other nutrients. Such a diet will quite certainly cause nutritional deficiencies in the long run. Therefore, the novice keeper should not think that by providing such a diet, he will be providing one that will be closest to the natural diet of the wild shamas.

Within the group of birds classified as insectivores (specialist feeders), the dietary habits and digestive capabilities may still differ to some extent, from one species of this group to another. Their different habitats that support different types of prey items could possibly be the reason behind these slight differences of their digestive adaptations. Therefore, when one species of insectivorous bird thrives on a certain captive diet, it is not necessarily so that all other insectivorous species will do well on this similar diet. An example from my own observations of the commonly kept insectivorous birds shows that the digestive capabilities of the white-rumped shama and that of its relative, the oriental magpie robin can be quite different. When both are fed on a captive diet that is high in chitin, shamas will regurgitate substantial amount of indigestible chitin throughout the day. Regurgitating pellets of undigested chitin is a common behavior of many species of insectivorous birds in the wild. However, the observation that chitin is better retained by the magpie robin and allowed to pass through its digestive tract, suggests that the magpie robin, when compared to the shama, may have a digestive system that is far better equipped to utilize the chitin component of the diet. In the case of the shama that do not retain them in its digestive tract at all, quite clearly, chitin has little or no nutritional value for this species.

Apart from the purpose to expel indigestible matter through the mouth, there are really no other significant benefits to birds from the behaviour of regurgitating indigestible food. In captivity therefore, there is no reason to encourage this natural behaviour in birds like the shama. Hence, if its captive diet comprises of too much indigestible chitin, it will be of no benefit, since it is also shown that shamas do not utilize whatever food value that may be present in these. On the contrary, regurgitation requires convulsive efforts and in the case of the shama, there seem to be significant amount of discomfort associated with this effort. They also seem to be affected by the presence of indigestible pellets that had formed in their crops and are yet to be ejected, often becoming inactive and unwilling to sing or eat until these are regurgitated. Even though the discomfort associated with a high chitin diet may not adversely affect the health of the captive shama, it will at the least, interfere with the performances of a male shama that is raised for the arena. Therefore, it is in my opinion that unlike some other insectivores, the shama should not be fed on a diet that is high in chitin. For this reason, food such as crickets and mealworms which are high in chitin should only be used sparingly when included in the captive diet of the shama.

Certain brands of dry pelleted food for insectivorous birds that are popular in the west may not necessarily be good for the captive shama. For one thing, some of them are tailored to the needs of insectivores from the temperate region and will include substantial amount of dried fruits. Although the digestive system of the captive shama can be conditioned to accomodate such an inclusion in its diet, it is however not a species that will thrive on nutrient dilute food such as fruits. Unlike the temperate insectivore whose digestive system is adapted to consuming nutrient dilute food during certain time of the year, the white-rumped shama, being a specialist feeder that feeds on a nutrient compact diet throughout the year, is by nature, a small eater that do not have the required capacity in its apettite for a nutrient dilute diet. Some of these pelleted dry food contains substantial percentage of crude fibre, often advertised to be necessary to simulate the chitin component of an insectivore's diet. In the case of the captive shama, I do not think that this is beneficial.