If you only need to protect a small area, you may want to try on of the following exclusion methods.
Bird netting is a net that covers plants and crops but still allows for airflow and sunlight. You can use this to protect gardens, berry bushes, or individual fruit trees.
Wire lines have been used most successfully with gulls and various species of waterfowl, but there is some evidence that it may also work for crows.
You can string parallel lines of of monofilament or wire over the site to be protected, at a height of 6-8’. Some people hang ribbons, strips of aluminum foil, or pie tins from the lines to make them more visible to birds. It may be, however, that the element of surprise the bird experiences when encountering nearly invisible lines, is what makes this method successful in preventing their landing on the protected area. Birds may also avoid these areas because a quick escape from them may not be possible if a predator approaches.