Deciphering Nature’s Signs

So much is happening in nature and in our human constructed world that we tend to ignore some of the most obvious events of the natural world. Plus there are literally thousands of sights and sounds vying for our attention and it takes a significant effort of will to focus and be observant. A certain training of the mind helps in watching even subconsciously for important clues and selecting them from the background “noise.”

Here are a few examples of what you might see while walking around our VA farm in the middle of summer. As I was toiling up a steep hill along my neighbor’s barbed wire cow fence, I was shocked to notice three green June beetles impaled on the wire! This was exciting since it was unexpected, and because I knew immediately what this must mean. It revealed that a loggerhead shrike was feeding in the vicinity; they are famous for impaling their extra prey on thorns and barbed wire. Yet I had not seen the bird, only interpreted its presence by this sign.

Our common milkweeds are in bloom in large numbers and I am on alert for signs that monarch caterpillars are present. Caterpillars are eating machines so the best indication they occur is the presence of their feces or “frass” and bite marks on the leaves. Since caterpillars often hide under the leaves, these two signs are crucial in finding them.

In June and July I often see strange white foamy patches in certain of our ponds. I know from experience that these are the remnants of bullfrog breeding from the previous night and there will be hundreds of embryos in these areas. They quickly dissipate as the eggs hatch and tadpoles disperse into the pond.

Within a mile of our farm there is the New River, which is said to be the second oldest river in the world (after the Nile). It has different aquatic fauna than our small spring fed streams and ponds and I often go there to see new species. This cobra clubtail dragonfly is a fierce predator on small insects; on a hot summer day it was “obelisking” or holding its abdomen in a vertical position to minimize heat gain from the sun. Nearby there was a damselfly that I never see on our ponds, a ruby spot damselfly. The male is much more brilliant than the female and is quite a spectacular fellow. Both of these species are characteristic of larger streams and rivers, presumably due to some specific but generally unknown requirements for the larvae and/or adults.

This tiger swallowtail was perching on dung and extending its proboscis, a clear sign of “puddling” behavior. This is well known to represent drinking of fluids from vertebrate digestion and excretion that contain needed salts, especially sodium, which are scarce in the diets of herbivores. I have become a big fan of horses on trails since their poop attracts beautiful butterflies and holds them for close observation.

We have planted cup plants (Silphium) which have large yellow blossoms in mid-summer attractive to butterflies. Here a pipevine swallowtail is finding nectar in the flowers while being protected from the attacks of birds by its black and blue coloration which advertises toxicity obtained as a caterpillar from its food plant (Aristolochia species). There are many other butterflies that mimic this coloration in an apparent bid to inhibit birds from attacking them. One of the most beautiful is this red spotted purple, a type of brushfoot butterfly (kin to admirals and buckeyes).

So remain alert in nature and you will observe a tiny fraction of what is actually happening, and be awe struck by the intricate and complex lives that our fellow creatures are engaged in. Trying to understand some of these remarkable stories enriches and enlarges our own existence beyond measure.

Bill Dunson

About Bill Dunson

Bill Dunson, born in rural Georgia, skipped 12th grade and went directly to Yale. Bill subsequent-ly received a PhD in Zoology from the University of Michigan, studying softshell turtles. Bill is Professor Emeritus of Pennsylvania State University thanks to a career spent entirely at that institution, teaching and doing research on the physio-logical ecology and ecotoxiciology of reptiles, amphibians and fish. Always curious about nature, Bill has dedicated his life to learning and sharing his knowledge with others. He has served on many advisory boards here in Southwest Florida to preserve the water that gives life to our region.

View all posts by Bill Dunson