March in the Sky Islands ushers in all manner of wild beasts. Migratory birds begin to trickle back to our local haunts. Various species of reptiles and amphibians make cameo appearances on the warmest of days. Legions of invertebrates come out of the woodwork. It’s a revival of life that we largely admire via our superb primate color vision—our eyes.
As you spy different wildlife species this month, contemplate how they might be seeing you, as well as the world at large. Evolution has produced a truly dazzling array of optic hardware. I may not be a soothsayer, but I predict that many eyes will fall upon you in March. Let me entice you to take a virtual walk through the Patagonia Mountains and San Rafael Grasslands, delving into the vision of several species you might encounter.
Your jaunt begins not far from Patagonia in a lower, albeit dry, stretch of Harshaw Creek. There you seek the shade of a small grove of netleaf hackberry trees. Leaning against a trunk to catch a better view of Red Mountain, you startle a butterfly. It had seen you all along, yet kept to its perch until you loomed too near. It’s an American Snout, which has evolved to mimic a dead leaf when perched on a twig—the better to dupe the ravenous eyes of predators. It skips through the air, taking in your behemoth form with its compound eyes—eyes that have many facets, each providing a separate yet overlapping image of you. When searching for nectar with its keen color vision, the American Snout is able to tell which blossoms are most promising, as, like most butterfly species, it can discern nectar supplies via the UV spectrum of light.
Further upstream along Harshaw Creek, your peripheral vision catches the aerial maneuvers of a soaring gray hawk, recently returned from Mexico. As the bird soars on rising thermals, you raise a pair of binoculars for a closer inspection.The hawk returns the favor with its large, forward-facing eyes. They easily pick you out of the landscape. How else would it be able to detect small reptilian and other prey from such a height, while coursing closer to the ground, or while perched in a tree?
Miles further, the stream comes to life, flowing strongly. Suddenly, a small animal scurries up a tree overhanging the water. A flash of turquoise confirms that you’ve met a male ornate tree lizard. Its vision has evolved to pinpoint small insects and other invertebrates, while also widely scanning for predators.
The gray hawk would like nothing better than to turn it into saurian sushi, but this lizard species is able to identify raptors flying high above. This ornate tree lizard has color vision, as natural selection has imbued at least the males with sexy, blue throat patches. The colors and patterns on the lizard’s back, which mimic tree bark, challenge the vision of even a gray hawk, as this species appears as just another patch of bark.
After snapping a few photos of the lizard, you notice a tiny creature hopping its way across a rock outcrop abutting the creek. You’re surprised to see a large pair of spider eyes returning your stare! Unlike many other species, jumping spiders have one main/central pair of eyes that dwarf their peripheral ones, providing some of the most acute vision among invertebrates. This allows it to track your movements in three dimensions and in color. Detailed vision also allows the spider to leap with great speed to either escape danger, travel along its chosen path, or to pounce upon small prey. The ultimate use of vision in jumping spiders is when a courting male artfully waves his pedipalps—a pair of appendages near the front-most legs—to win over a female. If her vision works according to plan, she’ll mate with her smaller suitor instead of eating him.
Many miles later, you enter the expansive San Rafael. A few hills into this sea of grass, a herd of pronghorn suddenly bolts. Despite being several miles away, they’ve easily picked you out from the largely treeless plains using their wide-angled vision that takes in 320 degrees. Pronghorn have some of the proportionately largest eyes of any mammal, affording them long distance vision adept at identifying far-flung threats. (It’s even been claimed that they should be able to see the rings of Saturn, on a clear night.) The trade-off is that they see in black and white. Combined with their great speed and endurance, the pronghorn’s vision renders them experts at avoiding predators and nosy humans alike.
As March progresses, try to see the world through the eyes of other species. Do they have color or black-and-white vision? Can they see well in dim conditions? Are they better equipped to see near and/or far? Imagine yourself as one of them, transforming not only how you see each species, but also yourself and the planet as a whole—an experience that should prove truly eye-opening!
Vincent Pinto and his wife, Claudia, run RAVENS-WAY WILD JOURNEYS, their Nature Adventure & Conservation organization devoted to protecting and promoting the unique biodiversity of the Sky Islands region. RWWJ offers a wide variety of private, custom-made courses, birding and biodiversity tours. Visit ravensnatureschool.org