It might depend on the location or the species. Behind my dad's place, there is a field. White-tailed deer come out of the woods at dusk to eat at the edge of t

It might depend on the location or the species. Behind my dad's place, there is a field. White-tailed deer come out of the woods at dusk to eat at the edge of the field. Every 15 seconds or so, the adults look up with their ears raised and wait a few seconds, then flick their white tail as they lower their head back down to eat. I'm not sure I can judge distance well, but I'd guess it's about 100 yards/meters across the field. There have been times when just by standing in the window watching them, they look and see me and get spooked and trot back into the woods. (On the other hand, there have been times when I walked out into the garage, opening and closing the door, and they look at me for a while but decide to continue eating.)