It is recommended that you use clean black-and-white newsprint, paper towels, or clean sheets of used computer printer paper. Sand, ground corncobs, or walnut shells may be sold by your pet supply store, but are not recommended as cage flooring materials because they tend to hide feces and discarded food quite well. This can cause a bird owner to forget to change the cage tray on the principle that if it doesn’t look dirty, it must not be dirty. This line of thinking can set up a thriving, robust colony of bacteria in the bottom of your bird’s cage, which can lead to a sick bird if you’re not careful. Newsprint and other paper products don’t hide the dirt; in fact, they seem to draw attention to it, which leads conscientious bird owners to keep their pets’ homes scrupulously clean.
You may see sandpaper or “gravel paper” sold in some pet stores as a cage tray liner. This product is supposed to provide a bird with an opportunity to ingest grit, which is purported to aid indigestion by providing coarse grinding material that helps break up food in the bird’s gizzard. However, many avian experts do not believe that a pet bird needs grit, and if a bird stands on rough sandpaper, it could cause foot problems. For your pet’s health, please don’t use these gravel-coated papers.