As children start getting out of school, woodland hiking picks up in Maine, and one appeal of this healthy sport is observing wildlife, flora and geological formations.

Nothing jump-starts an average hiker’s knowledge more than reading nature books with solid information on what to look for or what we’re seeing while walking through forests and fields.

Bernd Heinrich, a biology professor at the University of Vermont, has written several acclaimed nature books that take place in Maine and are must reads for hikers. He offers novice and veteran woodland wanderers a good place to start on the road to becoming a knowledgeable amateur naturalist.

Heinrich received much of his education in Maine and owns a second home in Perkins Township west of Farmington. The woodland setting around this modest dwelling has generated observations galore — fodder for his award-winning books.

This naturalist-scientist possesses incredible perspicacity, and one perfect example appeared in his “Summer World: A Season of Bounty” (HarperCollins Publishers), published in 2009.

Heinrich wrote about a behavioral trait of certain caterpillar species, beginning the passage on page 83.

“Once while still searching for caterpillars,” Heinrich began, “I saw something that made my eyes pop.”

Heinrich had noticed partially eaten leaves lying on the ground and surmised that caterpillars had left the shredded foliage there. They had fed on leaves in the upper canopy and then cut through the petiole of each chewed leaf so it would fall. For such a small creature, this required copious energy and precious time.

Heinrich knew caterpillars had done it, too. When trees shed foliage, the break occurs between the twig and leaf stem — not in the petiole — so this astute observer knew caterpillars had chopped the leaves off after feeding.

Heinrich decided that the caterpillar species had developed this tactic for long-term survival. They discarded feeding evidence to fool birds that could easily see partially eaten leaves in the tree canopy but might miss them on the ground, effectively stopping flying predators from keying on the caterpillars’ foraging area.

Another observation convinced Heinrich that his theory had merit. Birds leave spiny, bristly or poisonous caterpillars alone and concentrate on species with soft bodies and little or no hair — pretty much solid protein, minerals and so forth. Birds seldom bothered with less edible caterpillars, so those invertebrates felt no need to dispose of leaves.

I have noticed partially chewed leaves littering the ground but unlike Heinrich, could not figure out what it meant until reading his book.

This topic reminds me of my younger years as a bow hunter, baiting Maine bears:

One bait site in a cedar swamp had a boar bear visiting it, but the huge bruin was leaving no tracks. I knew it was a trophy, though.

While baiting the site before the hunting season opened, I had bumped into this big boy a mere 25 yards away. The encounter made the bear become strictly a nocturnal visitor from that day forward, and none of my tricks altered his nocturnal behavior.

Second, the bear had left canine-teeth marks on a Styrofoam tray covered with molasses. Measuring the bite gave me an idea of the bear’s size.

When the bear approached the bait, he used the same path, an old, abandoned tote road that included a short stretch of mud and another bare spot with soft loam. Much to my surprise, he would circumvent the perfect tracking media by walking through grass edging the road next to the mud and loam, eventually wearing a subtle trail with no tracks.

If it weren’t for the fact that the bear walked through a shallow, gravel-bed brook and dew-covered grass, I would have surmised he disliked getting wet feet. But he did get wet feet often and more importantly walked around the dry loam, leading me to surmise he deliberately avoided leaving tracks, a survival tactic that allowed him to grow that big, despite baiters.

Animals prove more clever than we think, even caterpillars. After myriad millennia, these little creatures learn to survive against huge odds.

It’s all there to see, and our education can begin or continue this very day.

Two other Heinrich titles, “A Year in the Maine Woods” (Addison Wesley) and “The Trees in My Forest” (Harper Perennial), are must reads, too, filled with mind-blowing observations.

 

Ken Allen of Belgrade Lakes is a writer, editor and photographer. He can be contacted at:

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