Why Do Some Birds Eat Grit?
Birds which peck grain and other seeds also peck grit to help them to digest these hard foods. Because birds have no teeth, the work of chewing, which would require muscles and strong jaw bones, is done by the gizzard. This makes it possible for the skull to be delicate in structure and therefore light in weight.
Grit is taken into the gizzard, or ventriculus, which has thick and often very muscular walls and the combined action of the two grinds down the hard food. The ventriculus is the back part of a bird’s stomach, the fore part is glandular and secretes digestive juices and is called the proventriculus. Food passes from the ventriculus to be absorbed by the intestines.
The necessity of providing grit to pet birds as an aid in digestion is controversial. Although there is a long history of feeding grit to pet birds, the practice has now come into question. Some wild birds eat grit, which passes to the gizzard where it helps in this grinding process. It aids in removing the outer fibrous shell around some seeds (e.g.; sunflower seeds), if the shell was not removed with the beak prior to the seed being swallowed.
The diet of wild birds is different than that of pet birds. Wild birds must eat whatever is available, and many of the seeds may have very tough shells or hulls, thus the need for grit. Doves and pigeons do not remove the hulls from seeds, so they also require grit.
Pet birds, on the other hand, are generally fed pelleted diets or seeds which are easily hulled and digested without the need for grit. The use of grit will not make up for offering a poor diet. For proper food digestion, it is more important that a bird be fed an easily-digestible, nutritionally-balanced diet which also includes fruits and vegetables.
Most authorities agree that healthy psittacines (e.g.; parrots, budgies, cockatiels) fed a proper diet do not need grit. Some studies have shown that passerines (e.g., canaries and finches) have a behavioral or nutritional need for the ingestion of soluble grit. No evidence suggests that the provision of insoluble grit in the canary diet has any benefit and over supplementation may lead to health problems. Soluble grit offered to passerines should only be in very small amounts – several grains every few weeks.
Birds with pancreatic disease (the pancreas produces most of the digestive enzymes) or certain digestive problems may benefit from the addition of small amounts of grit to their diet. If your bird has a digestive problem, consult your veterinarian regarding your bird’s need for grit.