Accipiters such as the goshawk leave a splash or streak of whitewash that radiates out from the feather pile, whereas owls leave small heaps of chalky whitewash on the ground. Hawks and owls regurgitate pellets that are accumulations of bones, teeth, hair, and other undigested materials. These are not usually found at the kill site, but instead accumulate along with whitewash beneath a nearby perch or nest site. Fresh pellets, especially of owls, are covered with a moist iridescent sheen. They can be carefully teased apart and examined to learn what the hawk or owl had been eating.
Owls gulp their food and swallow many bones along with the flesh.
These bones are only slightly digested and persist in the pellets. A pellet that contains large bones, such as those from the leg of a rabbit, is undoubtably from a great horned owl. Hawks feed more daintily and have stronger digestive juices than owls. Thus, hawk pellets contain fewer bones. These laws strictly prohibit the capture, killing, or possession of hawks or owls without special permit.