The ability to hide food is extremely important to ravens, and they behave completely differently when they feel they are being watched -- hiding food more quickly, for example, and are less likely to return to a hiding place for fear of revealing the location to a competitor. READ NEXT Drones are bad news for planes, but geese are a nightmare <img src="https://wi-images.condecdn.net/image/XD7Oe04wnvg/crop/200/square" class="global__image" /> Drones are bad news for planes, but geese are a nightmare By James Temperton The study replicated this behaviour. Two rooms were connected by windows and peepholes, both of which could be opened and closed. The ravens were trained to look through the peepholes to observe human experimenters making stashes of food. Finally, both windows were covered while a single peephole remained open -- and, though no bird was present, the ravens still hid the food as if they were being watched. - www.wired.co.uk