Cairn A cairn (duck or duckies) is a human-made pile (or stack) of stones. Cairns are used on the trail to direct hikers, bikers, or equestrians to the right direction of the trail. The top stone points to the direction. I have created this carin vase to symbolize my hiking adventures. I have had many never forgetting most pleasurable times on the trails of Nevada and California with very dear friends.