Grit, Oystershell and Cuttlebone - What are they?

Here is a little background on the difference between "grit", "oystershell", "cuttlebone", etc...

"Grit" is usually granite.  A stone.  This is also the main ingredient in things like "Calcium Grit" and "Charcoal grit". Prior to current thinking, almost all bird species were provided with "grit" as it was thought to aid digestion, (this was basically due to the fact that poultry is fed grit, and many pet bird diets were based on poultry research). However, it was found that free feeding grit to birds that hull their seeds could cause "grit impaction", (the over consumption of grit which led to intestinal blockage).  It was also found that grit was not a necessary addition to the diet of a bird who hulled its seed, (including canaries/finches, parrot-type birds, etc.), and digestion occurred without it just fine.

Birds that DO need grit available are the kind that swallow their food whole...poultry, pigeons, doves, ducks, geese, quail, etc.  In this case, swallowed seeds and foods are broken down and "hulled" with the aid of small stone rolling around in the gut.  These birds do not "chew", so therefore, need some digestive assistance.  The stones break down over a very long period of time, and are not immediately digested. But for the majority of pet birds, granite grit is now considered non-essential to the diet, and may pose a risk if freely fed.

Charcoal of any kind is not advised, since it can interfere with absorption of nutrients.  Charcoal, is used, however, in emergency cases where poison or toxic substances have been ingested...but this should be the only time charcoal is given to a bird, and it should be done so by a professional.
Oyster shell, cuttlebone and mineral block, on the other hand DOES break down in the digestive tract and is eliminated as any other foods.  Oyster shell and cuttlebone are sources of calcium...oyster shell being a shell, and cuttlebone being the skeleton of the cuttlefish.  Both provide calcium carbonate.  Oyster shell is sometimes confused with "grit" because some references call it "oyster shell grit", but if the ingredients listed are just oyster shell,  it can be used as an alternative calcium source.  For small birds, crushed oyster shell is available, rather than the larger "big flake" form.
Always purchase oyster shell from a reputable source, (for example do not go out and gather oyster shells off the beach, which may be a contaminated source).

Mineral blocks contain calcium, but also include other minerals , so it is usually advised that a mineral block be available as well as one of the "straight" calcium sources. (For budgies and some types of exotic finch, it is also advised that your mineral block contain iodine for the prevention of gout...a condition that these particular birds are suseptible to).

 - Parrots, Parrots, Parrots would like to thank, Dawn Woodland for allowing us to post this information. Dawn was Senior Wildlife Rehabilitator at Vancouver Island’s largest Wildlife Rehabilitation facility, servicing 1,600 sick, injured, and orphaned birds and mammals per year. She is currently retired, but continues to volunteer in the avian community, and spends much time lavishing attention on her own flock of birds…including two adorable parrotlets…Kinney and Brockley.