This is either a complete coincidence or it really works. I have done this many times and it really seems to work. Discovered it accidentally and then tried an experiment to see what happened. If I send a child out onto the reef and have them 'play' with the snapping clam a few times, like 3 or 4 open and close snaps, it seems to make the collectible items appear very shortly after. Feathers, turtle shells, mushrooms and seashells. Somewhere between 10 and 30 seconds. Helpful to boost your tech points!