Middle August is not a Time for Doldrums

So far this summer has been quite wet and warm but we have entered a somewhat cooler although still wet period. It has been a pleasure to be able to go outside with high temperatures only near 80 F. Rapid drying of ephemeral pools has also decreased the number of mosquitos and ticks have been scarce this year. But hiking options are still reduced by the effects of flooding from tropical storm Chantal which swept away many small bridges and blocked many trails with debris.

I explored a trail along Bolin Creek in Chapel Hill NC which starts from Tripp Farm Rd parking. Some very interesting ecological lessons (forest forensics) are on display along this creek. Some uplands which are mainly pine trees are probably only 30-40 years from being cleared land and are completely without an understory of bushes and small trees. This is somewhat of a mystery but is most likely due to herbivory by overabundant deer. Flood plains down along the creek are also open under mostly hardwood trees, probably due to the periodic flooding and deer herbivory. Surprisingly the only areas with a dense understory were mainly overgrown with Russian olive, a non-native shrub. Although this is usually considered a very bad species it does have two good aspects. First the fruit is eaten by native species and second the dense undergrowth fosters breeding of birds such as hooded warblers.

I gained another ecological lesson in the Home Depot parking lot! There was a flock of Canada geese grazing on grassy areas. These beautiful but problematic geese are of course native but did not historically breed this far south. Some birds were originally “short stopped” by clipping their wings and they subsequently bred far south of their normal breeding range. Their progeny now breed here thinking it is their natural range which it is not. They cause a great deal of problems on lakes and rivers by their numerous feces and noisy and aggressive behavior.

One of the most common birds in my yard does not cause any problems. Cardinals are a very abundant breeding bird and dominate the sunflower feeders on my back porch. This time of year the bright red males can be seen feeding the large fledglings. Such “big babies” are out of the nest but still obviously dependent on handouts from Dad. This is rather reminiscent of human kids who are reluctant to leave home!

As the flowers of July turn into August seeds the goldfinches have a bonanza of food to choose from. Both females and males feed on the seeds of purple coneflowers. I have to remember not to deadhead too many of these flowers to allow the seeds to develop for the birds. Our human desire to make things “neat” is rarely a good thing for wildlife.

Butterflies have been very abundant in my backyard in August. A new species has appeared, the sleepy orange, which is part of the sulphur group. They are confusing to identify. Most feed on cassias as caterpillars. The “snout” feeds on hackberry as a caterpillar and rarely comes to flowers. The pipevine swallowtail is the toxic model for the “black and blue” mimicry complex and feeds on the peculiar pipevine.

Two moths that are conspicuous when present are the luna moth with its strange greenish color, and the caterpillars of the tobacco hornworm or Carolina sphinx moth, with a night flying adult. The hornworms are infamous for eating tomato plants and are remarkably camouflaged. They will eat several members of the nightshade family (tomato, tobacco and potato) despite their common names.

One of the most interesting traits of butterflies is their propensity to eat vertebrate fecal material. This is sometimes called “puddling” as it relates to feces and any moist material which contains sodium. Plant material is normally low in sodium yet it is needed for animal life. So butterflies (such as this red spotted purple, tiger swallowtail and silver spotted skipper) are clustered on the white fecal matter from a bird. If you ever lived up north where road salt is spread in winter you will have seen groundhogs stretched out licking the roadside for remnants of road salt for the same reason.

My yard has many flowers and butterflies and thus a few spiders will show up to catch the butterflies. This young golden garden spider has set up a web in the midst of some flowers. The function of the zig zag stabilamenta ( https://en.wikipedia.org/wiki/Stabilimentum ) is the subject of considerable debate not yet conclusively decided. But it clearly is of use to orb web spiders.

I had some weakened trees cut down recently which caused considerable disruption of the nearby forest soil. This has resulted in appearance of an early successional plant, the pokeweed, which has not likely grown in this area for many years. These species have a seed bank which lasts for the many years between the times when conditions are right for weedy growth. This also illustrates why few farmers use anything but no-till agriculture to avoid the germination of such weedy species.

Although I live next to a large river, the animals living in the river are mostly a mystery to me. So it is exciting when my relatives (here grandson Peter and a friend from Iowa -Cael) go catch and release fishing. Just getting down the steep bank to the river with kayaks is an adventure plus avoiding the rocks in a swift current. They caught a variety of fish including redbreast sunfish and largemouth bass.

When the middle of Summer arrives can Fall be far away? Certainly as the dogwood fruits start to ripen my thoughts turn to Fall bird migration. The most exciting time is September when the northern thrushes (Swainson’s and gray-cheeked) pass though heading to S America and stop briefly to feed on my abundant dogwood berries. I hope to make one more trip to northern latitudes to listen to their fantastic spring songs in the northern forests.