Wednesday, July 16, 2008

Fruits in Shama's Diet

Posted: Thu Mar 08, 2007 6:58 am Post subject:


I am grateful to Jeffrey Low for drawing my attention to a scientific study at Standford University on the diet on birds which includes an observation on fruits and other vegetable matter as part of an insectivorous bird's diet. The article answers my questions on an aspect of the shama's nutrition that I needed answers but I had not expected to find any study on it and, as so often happens when the mind is closed, I had not tried to look further.

Quote: Many species that are primarily insectivorous specialize in devouring one common kind of insect at one time, switch to another insect species when the first kind of bug completes its flight season (or is decimated by predators), and then move on to others until insect activity becomes less common in the fall. The birds then may begin to supplement their diets with vegetable matter such as berries, or else depart for southern climes where insects are still active (and where many species that eat insects in the north eat primarily, if not exclusively, fruit).

As Jeffrey notes, in the tropics, shamas and other insectivorous birds do not need to adapt to such situations. Pure insectivorous birds from the tropics may not have a digestive system that had evolved to accomodate fruits like their cousins in other regions with 4 seasons. Jeffrey has further noted that the guts of the insects that our birds eat, contain vegetable/plant materials that should cater for any need for nutrients from such sources. Insects feed on plant materials and the insects are eaten whole including the contents of their guts.

Jeffrey and I have both seen healthy captive shamas that were never fed fruits.

The above does not mean that Jeffrey and I disapprove of fruits being fed to shamas. Our thinking is that it may not be nessary to form part of the shamas diet. Nevertheless, there may be benefit in providing fruits and I hope that those who feed fruits will contribut their thoughts and experiences. Axel Voltz, for one, believes in the value of fruits. He cust small pieces of apple in longish pieces to simulate small worms and he says that his shamas sometimes prefers them even to mealworms.

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