Lately there has been some debate going on whether or not parrots need of grit. This is a common question of concern to bird owners, as well as a source of disagreement. Understanding what grit is, the purpose, and the possible problems that could result from its use, can help you make an educated decision on whether or not to offer it to your bird.
The Purpose of Grit
“Grit is used by birds to aid in digestion of seeds” is a comment heard repeatedly in both outdated parrot care books or other related texts. What this comment fails to convey is that grit is used by birds to aid in the digestion of whole, intact seeds. Birds digestive enzymes work amazingly well in digesting the inner portion of the seeds, but can have difficulty in breaking down the hull (which is the fibrous outer coating). Grit, in the avian ventriculus, aids in grinding and wearing away the outer shell of the seeds enabling the digestive enzymes to reach the nutrients within the inner portion of the seed.
What Exactly Is Grit?
The term grit is often loosely used and not entirely explained. There are two groups of substances that go by the name of grit -- soluble and insoluble. Insoluble grit is the type that is being discussed here. It is composed of minute substances such as sandstone and other minerals often found in dirt and clays. Insoluble grit cannot be digested and will remain in the body until expelled.
Soluble grit is organic and can include crushed shells ... often oyster shells or cuttlebone. Since soluble grit is mostly calcium carbonate it is easily digested by the acids found in the proventriculus and poses little danger of accumulating in the digestive system. However, while soluble grit can offer an alternative source of calcium it does little in actually aiding the digestion of seeds.
Do Birds Really Require Grit?
In the United States, the general consensus seems to be "no". The purpose of grit is to remove the outer coatings of whole seeds, so it seems reasonable to assume that only birds which consume seeds intact, such as doves, require grit in their diet. Birds such as parrots, and even finches and canaries, hull their seeds therefore not needing the extra aid that grit would provide. In fact, some species of parrots have ridges on the inside portion of their upper beak that is believed to aid in the shelling of seeds. The seed is held in place by the ridges, while the lower beak is used to crack and remove the hull. Birds on a pelleted diet should not require grit either. In the US, the use of grit is generally discouraged, especially if offered freely, which may lead to obstructive gastritis. Although in Australia, grit is commonly given to pet birds with few problems being reported. At the time this article was written there is no explanation for these interesting geographical differences.
If given freely some birds may over-consume grit products leading to a possibility of impaction. It is also recommended to check the contents of any commercially-made grit mixtures as some may contain charcoal. Charcoal can affect the absorption of vitamins resulting in deficiencies.
In conclusion, the benefit of grit for parrots and softbills has not been positively demonstrated. Potential risks have been observed, as well as potential health benefits. If offered at all, we recommend offering it in moderation.