Turkey’s eyes are key to staying alive in wilderness

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It should surprise no experienced hunter or birder that wild turkeys have incredible eyesight.

One moment you’re looking at a big bird, and the next moment it’s gone. You swear you didn’t move a muscle, but obviously you did. And right now, as trees are losing their leaves, the problem is exaggerated.

Whether you’re lining up a kill shot or just trying to get a good look, clearer lines of sight give the advantage to the turkey. A turkey’s disappearing act is especially impressive for a bird that can weigh more than 20 pounds, run 25 miles per hour, and fly more than 50 miles per hour.

One reason turkeys are so elusive is that they enjoy the benefits of one of the most complex eyes in the vertebrate world. They can detect even slight movements at great distances. That’s how they detect predators such as coyotes, bobcats, and great horned owls.

Unique physiology

Turkey retinas have seven different types of photoreceptors, one type of rod cell and six different types of cone cells. Rods detect light intensity, and cones detect color.

Human retinas contain just a single type of rod and three types of cones. Based on the abundance of cone cells, it’s clear that turkeys have excellent color vision. And that should be no surprise given the multicolored fleshy heads male sport during the mating season.

For detecting human stalkers, however, it is one particular type of color-sensitive cone cell that gives turkeys almost super vision. These cone cells are sensitive to UV light, so they see things that we do not. This is also true for many other birds and mammals.

Turkey clothes

Turkeys’ sensitivity to UV light puts inexperienced turkey hunters and birders at a disadvantage. Even if you remain motionless, clothing can make a stationary observer impossible to miss. Laundry detergents that “whiten and brighten” clothing leave behind a UV residue. And the more often clothing is washed with these detergents, the more UV residue they contain.

This is also sometimes true for brand new clothing, even camo gear. So hunters and birders wearing hunting clothing or old favorites that have been washed many times almost glow to the eyes of turkeys.

One remedy is to wash your “turkey clothing” with detergents that do not have brighteners. Read the label.

Peripheral vision

Turkeys also have excellent peripheral vision. Like most birds their eyes are positioned on the sides of their head giving them a field of view of approximately 270 degrees.

Combine that with a flexible neck that can turn almost completely around, and turkeys can see 360 degrees with just a slight turn of the head. It’s no wonder they spook so easily.

Compared to human’s binocular, 180-degree field of vision, turkeys don’t miss much visually.

One drawback to turkey eyes being on the side of the head is that they lack three-dimensional vision. Though this would seem to be a significant disadvantage, they compensate by bobbing their head up and down enabling their eyes to gather information about relative distances and apparent depths of field. So lack of true 3-D vision is not a problem for turkeys.

Tough game

Thanks to razor sharp vision, sensitivity to UV light, and near 360 degree field of view, wild turkeys are hyper-vigilant regarding their visual environment. That’s why stalking turkeys and just getting a good look at them from a blind is difficult.

Whether hunting or birding, a better strategy might be to find a comfortable spot at the base of a big tree and let the turkey come to you.

As you enjoy Thanksgiving dinner in a few weeks, appreciate the visual adaptations that enable wild turkeys to live about two years in nature, and marvel that banded individuals are known to have lived longer than 10 years in the wild.

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Scott Shalaway, who holds a Ph.D. in wildlife ecology from Michigan State University, writes from his home in rural West Virginia. A former faculty member at Oklahoma State University and the University of Oklahoma Biological Station, he has been writing a weekly nature column for newspapers and freelancing for magazines since 1986. He can be heard on Birds & Nature from 3-4 p.m. Sunday afternoons on 620 KHB Radio, Pittsburgh, or live online anywhere at www.khbradio.com, or on the Tune-In radio app. Visit his website at www.drshalaway.com or contact him directly at sshalaway@aol.com or 2222 Fish Ridge Road, Cameron, WV 26033.

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