In the confines of a box, they usually will aim for a corner. In a few days the box becomes soiled and smelly. A good way to make it easier to clean is to line the box with a plastic bag and cover the bottom with several layers of newspapers. Every few days simply remove the bag and the papers and discard them. The bottom of the box can be covered with shavings or straw, but this makes it difficult to keep track of food that is left in the cage.
Most baby birds begin their lives in a platform or cup-shaped nest.
Usually only younger nestlings need help in this matter and hawks tend to require it more than owls. Otherwise, put in a shallow dish lined with straw, crumpled paper or old rags to make the right shape for the little bird. Young raptors are often several weeks old before they can stand up and even then may spend most of their time sitting down. They behave much like any animal baby, eating, then lying down to sleep. The box should be kept in a place that is free of drafts or extremes of temperature and protected from people and pets.