I have tried a simple trick with cacti and water. If you don't have cacti then its easy to find on a desert, just go during the day in a boat. The trick is to make a bowl in the ground by mining the dirt pretty big and filling it with water running towards the center. Then have a wall of cacti at least two blocks from the end all the way around and wait in the center for anything dropped to flow towards you. If skeletons come and can hit you try a wall of glass to allow yourself to be seen but I have rarely seen those on my island and haven't needed it.