Animals notice all movement, hard edges, shiny stuff, blinking eyeballs stuff like that. Concealment from humans is different-with humans camo is very effective-we know exactly how humans see. How exactly animals see color is still not completely understood. Plaid works great as does anything else that has broken and or soft edges-which is why wool is so effective pretty much regardless of color.
Blinking eyeballs and being stared at they really notice! Next time you see an animal that is out of season, or you have no interest in; experiment. Walk away in plain sight, walk at an angle towards them but not at them, and don't look at them at all-just peripheral vision-pretend you never saw them-the results may surprise you.