Rock Duck 石 鴨

石 鴨 係 乜 0野 嚟 0架? What's a rock duck? When I first started hiking, I noticed that the trail guides mentioned "rock ducks" and said that hikers should watch for them. It took me awhile to figure out what they were talking about (see photo above). Rock ducks are little piles of rocks that mark a trail, especially in areas where it otherwise would be hard to follow the trail. I guess they call them ducks because the typical pile looks like a duck's body, with the biggest rock on the bottom and the smallest rock on top (OK, it takes a good imagination). From the photo, you can see how it can be difficult to follow a trail through a rocky area without having rock ducks to guide your path. On many hikes, rock ducks have helped me greatly, sometimes keeping me from getting lost. On my hikes in HK in 2001 and 2004, I don't recall having seen any rock ducks. Instead, HK hikers seem to mark their trails with arrows, ribbons, and ropes. Does anyone know whether rock ducks exist in HK?
P.S. Speaking of ducks, for anyone interested in the shop where I got 滷 水 鵝 in HK, I added the name
below.