is not a threat to its young. Jeffrey Walters provided evidence that lapwings possessed the ability to distinguish between different types of predators of varying threat levels, a behavior which is presumably learned, perhaps through cultural transmission. Armstrong additionally noted that displaying animals were rarely captured by predators, as would be expected if the display were truly uncontrolled, and that the movements seemed to show signs of some sort of control by the animal, although likely not conscious, intelligent control. One example of apparent control is attention seemingly paid to routes used by the displaying animal when moving away from the nest. Furthermore, researchers have noted parent animals moving towards the predator during the display. While some of these cases could be attributed to mistakes made during "partial paralysis", in the case described by Wiklund and Stigh, snowy owls consistently walked or ran towards the predator while displaying, suggesting that the action was deliberate. An additional hypothesis in alignment with Armstrong's ideas about conflicting impulses suggests that the incorporation of sexual and threat displays into the distraction display may represent displacement. Displacement occurs when an animal, unable to satisfy two conflicting impulses, may initiate an out-of-context behavior to "vent". If a displacement behavior served an adaptive function, such as increased survival of the young, then it may have experienced positive selection and become ritualized and stereotyped in its new context. In any case, there are some forms of distraction display which may in fact have evolved from stress responses, an idea more in alignment with Lack's hypothesis. One of these is the "rodent-run" display, in which a bird fluffs its feathers to mimic the fur of a rodent and scurries away from the nest. It is possible that this display originates from a feather ruffling reflex to alarm. Adaptive functions There are several conditions in which distraction display may be advantageous to the animal, such that the incorporation of displacement or stress behaviors into offspring defense will most likely undergo positive selection. Most such cases depend upon the condition or location of the nest: distraction display has tended to evolve in species whose nests alone do not provide a substantial physical barrier to predators, and in those that nest on exposed terrain or close to the ground. If the nest is on open terrain, the parent may perceive predators at a greater distance and be able to leave the nest