Outdoor Life has the story.
This information comes from PhD work at the University of Georgia (Blaise Newman, a PhD student at UGA) and which is sponsored by Sitka (which makes perfect sense).
See the link for the details, but here is the BLUF. Avoid blues. Avoid anything you might wash your gear or clothing in detergent containing UV brighteners.
What’s even more interesting is that a deer’s ability to see in the blue spectrum dictates where they move and when. Newman’s most recent project touched on this connection by tracking whitetail bucks in Florida with GPS collars and seeing how they moved through different landscapes at different times of day. She found that these bucks often chose to move through more open and brightly lit areas that reflected plenty of blue light including UV.
“They’re actually moving through an environment that makes it easier to detect you,” she says. “One way I always relate it is if you had the option to walk down a dark alley or a well-lit alley, which would you choose to move through?”
Newman also evaluated how deer move during low-light hours by hooking them up to an electroretinography machine and measuring their response to different light stimuli. (This is essentially the same technique that was used in the Deer Lab’s 1992 color vision study.) She found that deer were most sensitive to light and movement under twilight conditions, which supports the idea that deer are more active at dusk and dawn because that’s when their eyes function the best.
“One of the most interesting things we found is that deer eyes can detect the best, and are most sensitive, during twilight periods,” Newman says. “So, if you’ve been hunting all day just waiting for that buck to come by, and he’s finally coming out at twilight, you better be careful because his vision is the most sensitive it’s been all day.”
If deer vision seems inferior to ours, that’s only because we see the world through human eyes. As apex predators and tool developers, it’s beneficial for us to see in finer detail and to be able to recognize a wide range of colors. These subtleties aren’t so important to deer, though. Their eyes have evolved to prioritize detection over detail, and their abilities in this department are vastly superior to our own.
“Deer are a prey species,” Newman says. “Having detailed discrimination isn’t really important to deer. They just need to be able to detect and escape something.”
When it comes to color vision in particular, Newman explains that deer benefit from having less “chromatic noise.” By not having to process so many colors in the retina, their eyes can detect movement more quickly and easily. This means that deer can process visual cues much faster than humans do.
“They see motion at an astounding rate compared to our own ability,” she says. “The other aspect is temporal resolution—the time interval over which you integrate information—and their temporal processing just outstrips ours.”
Movement and blues give us away.
Orange, not so much. It appears grey to them.
