Grit – What Is It and Who Needs It?
You have a bird – and you've heard of grit. You've noticed these bags of "sand" in your bird supply aisle of the store. You may have offered it to your bird because you thought it was what you were supposed to do. Or maybe you've heard it's dangerous. But in actuality, you don't really know what – if anything – you are supposed to do.
Grit – What is it?
Grit is made primarily from ground up minerals and sand. Some of the substances used are insoluble and cannot be digested. These include silicates and sandstone. Soluble, and therefore digestible, grit is primarily made of limestone, which is calcium carbonate. The soluble grit can be made from cuttlebones or from ground up oyster shells.
Grit for birds is specially formulated and is not the same thing as offering sand from a sandbox or small pieces of gravel. If you plan to offer your bird grit, buy only manufactured grit from a reputable company. There have been some reports of lead contamination from improperly collected oyster shells. If you limit your purchases to reputable brands, contamination is unlikely.
What Does Grit Do?
Birds in the wild tend to eat a significant amount of food. After all, they burn a lot of calories flying throughout the day. Birds are not too particular and will ingest some items that are easy to digest and some items that are not. The purpose of grit is thought to help the bird grind up difficult to digest items. By grinding, it is thought that these food items become better utilized by the bird. The grit is mostly undigestible material. It will stay in the ventriculus, or gizzard, for months to years until it is passed in the stool.
The gizzard is the primary grinding organ. This muscular part of the digestive system attempts to grind up large particles, such as husks and shells. With the assistance of rocks or sand, the grinding becomes easy and more effective.
For birds in captivity, their diets are selected for them. Most seeds are already husked or shelled and can be easily broken up by the bird's beak and gizzard. The ideal diet of pellets is even easier to digest. Whether or not birds in captivity need grit is a question of ongoing debate.
Who Needs Grit?
Since the primary purpose of grit is to help remove husks and shells from seeds, birds that ingest whole seeds, like doves, would likely be the best candidates for needing grit in their diets.
In the psittacine world, most parrots are able to remove the husks and shells with their beaks. For this reason, these species do not require grit in their diets. In the passerine world, canaries, finches, etc, are also usually able to remove the shells with their beaks and do not typically need grit to help in digestion. And, as mentioned earlier, birds on pelleted diets don't need grit.
Whether or not you offer your bird grit is a personal choice. Many birds have lived long healthy lives without ever ingesting grit. When fed an easily digested, appropriate diet, grit is not a dietary requirement.
If you feel that grit will help your bird, or if your veterinarian has recommended grit to help with digestive problems, make sure you offer the grit sparingly. Don't just fill a cup with grit and allow your bird free access. Over-ingestion of grit has caused intestinal obstructions and impactions. One suggestion is to offer a very small amount of grit, such as 1/8 – 1/2 teaspoon every 2 years. (Yes, every 2 years). Since insoluble grit will remain in the gizzard for months to years, very little is needed, if any at all. Some people recommend a small amount of soluble grit every few weeks. Consult your veterinarian to determine which is best for your specific bird.
What To Watch For
Grit is a controversial issue because of the problems it can cause. Overuse can lead to impactions and obstructions. Some grit formulations have charcoal included. Try to avoid these mixtures since charcoal can affect the absorption of certain necessary vitamins and minerals.