Why do birds eat gravel and sand?

Answered by Randy McIntyre

Birds eat gravel and sand, also known as grit, for several reasons. The main purpose of grit is to aid in the digestion of food. Birds have a unique digestive system that allows them to consume a wide variety of food items, including seeds, insects, fruits, and even small prey. However, not all of these items are easily digestible.

When birds eat, they swallow their food whole or in large pieces. Some of these food items may be difficult to break down in the stomach and intestines. This is where grit comes into play. Grit is mostly composed of small, hard particles such as gravel, sand, and small stones. When birds ingest grit, it settles in their gizzard, a specialized muscular organ in their digestive system.

The gizzard acts as a grinding chamber or a “second stomach” for birds. It contains strong muscles that contract and grind the food, along with the grit, into smaller pieces. The grit acts as an abrasive material, helping to break down tough food items like seeds, shells, and insect exoskeletons. By grinding the food, the bird increases the surface area of the ingested material, making it easier to digest and extract nutrients from.

Grit also aids in the mechanical breakdown of food. When birds consume items like fruits or berries, the seeds can be quite tough and resistant to digestion. The grit in their gizzard helps to crush these seeds, allowing the bird to access the nutrients inside. Without grit, these seeds may pass through the digestive system intact and be excreted without providing any nutritional value.

It is worth noting that not all birds require grit in their diet. Some species, such as pigeons and doves, have a specialized digestive system that enables them to break down tough food items without the need for grit. However, many other bird species, especially those that consume hard seeds or insects, rely on grit for efficient digestion.

In my personal experience as a bird enthusiast, I have observed birds actively seeking out grit in their natural habitats. They often pick up small stones, pebbles, or sand from the ground and swallow them. This behavior is instinctual and ingrained in their natural feeding habits. Additionally, in captivity, bird owners often provide grit as a supplement to ensure their pet birds have access to the necessary grinding material.

To summarize, birds eat gravel and sand, or grit, to aid in the digestion of food. Grit acts as an abrasive material in the bird’s gizzard, helping to grind down tough food items and increase the efficiency of digestion. It is an essential component for birds that consume hard seeds, shells, or insect exoskeletons. While not all bird species require grit, it is a natural behavior observed in many birds and can be provided as a supplement for captive birds.