How to Identify Owl Pellets

Look at the habitat where you found the owl pellet. While there is much overlap, different owl species favor different landscapes: Great gray owls haunt deep, dark conifer woods in mountains and boreal zones; barn owls more typically frequent mosaics of fields and woodlot. A pellet found in an urban area, such as a city park or cemetery, might belong to a species tolerant of humans, like the great horned owl, a near-ubiquitous denizen of all sorts of North American habitats.

Consider the pellet's size. Again, there is too much variation within species to make this a firm measure, but larger owls will generally produce larger pellets. Nonetheless, pellet size does relate somewhat to that of the prey being eaten and owls eat a variety of sized animals, from insects to big waterfowl and skunks. Also, note that owls, when disturbed, may eject larger, rougher pellets than normal, as they haven't had time to be fully compacted.

Make note of other characteristics, like color and consistency, in the context of size. Horned owls often eject large, firm, cylinder-shaped pellets, while elf owls---many times smaller and insectivorous---leave drier, loose pellets of tiny dimension.

Dissect the pellet and look for prey remains, using tweezers, a magnifying glass and gloves. You might find husks of insects in the pellets of smaller species, like screech owls. Many medium- to large-sized owls target rodents and shrews. Great horned owls, the most formidable and opportunistic of North America's species, are the most likely culprits if bone bits of larger animals are discovered.