Saturday, October 1, 2011

GREAT EXPECTATIONS: October in the Piedmont

Birds.− October marks the beginning of food-caching -- a food storage strategy developed to sustain year-round avian residents throughout the lean winter. Caching strategies vary by species: red-bellied woodpeckers might store acorns in holes high up in the cracks and cavities of trees, while American crows might simply thrust a left-over meal into the loose soil on the ground. Great horned owls have even been known to thaw out cached meals of mice and insects by sitting on them like eggs!

This October, a number of winter residents will return to the Piedmont. Lucky observers might discover a common loon or even a horned grebe, a small water bird that can travel 500 feet underwater and stay there for up to three minutes. Migrant warblers continue to pass through North Carolina as they head towards the neotropics for the winter, often flocking with those food-hoarding Carolina chickadees and tufted titmice. Meanwhile, sightings of chimney swifts, most swallow species and ruby-throated hummingbirds continue to diminish this month.

Although peaking in September, broad-winged hawks continue to migrate south this month, returning to their winter homes in the Caribbean and South America. This time of year, they are sometimes seen kettling, or wheeling and circling in groups of tens to hundreds of broad-winged hawks that are sometime joined by ospreys and American kestrels. These magnificent buteos, with their broad wings and round tails, make use of thermal and deflective currents (i.e., currents that form when air is forced upward after hitting the side of a mountain) to ease their journey southward. Although rare, large groups of broad-winged hawks occasionally fly through the Piedmont in early October: in 2009, 125 broad-winged hawks were reported flying over Greensboro, NC.

Butterflies & Moths.− Butterfly watchers can expect a decline in butterfly sightings this month, with the exception of some of the sulphurs and whites (family: Pieridae). Sleepy oranges will be out showing off the dark reddish-orange undersides that many butterflies sport in fall and winter. Many skippers can still be seen this month, including the brown and white patterned common checkered skipper, and dark brown, white flecked clouded skippers. Monarchs continue to migrate southward this month to their winter residence in Mexico.

In late September and early October, plenty of bizarre caterpillars can be found. They may look soft and cuddly, but many sport stinging hairs. The variable oakleaf moth caterpillar, and its nearly identical congener – the double-lined prominent, is one species that roams the Triangle during October. The caterpillar is green, with faint white stripes and straight black hairs and gives the impression that it is coming out of its skin. These caterpillars feed voraciously on the foliage of oaks, preferring white oaks. This species overwinters in cocoons beneath leaf litter on the ground, and emerges as drab grayish-tan adults in late spring.

Reptiles & Amphibians.− Continue to keep an eye out for snakes and turtles, especially copperheads that become especially well-camouflaged after the leaves begin to fall. Although you may still hear frogs and toads calling this month, large choruses won’t start up again until January.

Other Insects.− This month, keep an eye open for garden spider and praying mantis egg cases. Also, the work of twig girdlers (Oncideres cingulata) becomes evident in the form of neatly broken twig ends littering the forest floor. In late summer, female twig girdlers – large, dusky beetles – lay their eggs at the tip of a branch, and girdle the twig so that eventually it falls off, allowing her offspring to overwinter in and eventually feed on the twig and surrounding debris.

This month, look out for green lynx spiders, medium bright green spiders that ambush their prey. This time of year, some spiders will be perched on shrubs and flowers hunting bumblebees, butterflies and moths, while many female green lynx spiders are vigorously protecting large egg cases containing 200 eggs.

In Bloom this Month.− Be on the lookout for some striking October flowers; the subtle beauty of our native grasses in flower is especially interesting.

In Bloom:

WINGSTEM – Actinomeris alternifolia

BLUE MISTFLOWER - Conoclinium coelestinum

COMMON SNEEZEWEED - Helenium autumnale

SCARLET ROSE-MALLOW – Hibiscus coccineus

BLACK-EYED SUSAN – Rudbeckia sp.


GREAT LOBELIA – Lobelia siphilitica
DOWNY LOBELIA – Lobelia puberula

ROSINWEED(S) – Silphium spp.

GOLDENROD(S) – Solidago spp.

INDIAN GRASS – Sorghastrum nutans

IRONWEED(S) - Vernonia spp

In Fruit:

HEARTS-A-BUSTIN’ – Euonymus americanus

MUSCADINES – Vitis rotundifolia

Wildlife Profile.− This month’s wildlife profile is the TUSSOCK MOTH (Family: Erebidae, Subfamilies: Arctiinae & Lymantriinae), in honor of the numerous tussock moth caterpillars that can be found in early fall. These caterpillars look fuzzy, covered with tufts of hair-like setae and adorned with extra long tufts referred to as “hair pencils”.

The caterpillars range in color from cream with white and black tufts (like the Banded Tussock Moth, Halysidota tessellaris) to bright orange and black with white hair pencils (like the Spotted Tussock Moth, Lophocampa maculata.) The Banded Tussock Moth caterpillars feed on hackberry and oak, among many other trees. In autumn, they form gray cocoons and remain as pupa over-winter. Adults are tan with dark tan bands etched in black stretching across their wings. They also have hairy teal and orange thorax (right behind the head). To make themselves distasteful to predators, adult moths acquire alkaloid compounds from the leaves of plants. To do this, they regurgitate on the leaves of decaying plants and then drink the fluid, now mixed with alkaloids from the surface of the leaf, back up.

Some setae of these wondrously wild caterpillars produce a painful and poisonous sting, such as the White-Marked Tussock Moth (Orgyia leucostigma) with its distinctive red head, black and white striped body and four dense tufts (in white, gray or yellow) on its first four abdominal segments. White-Marked Tussock Moth larva are also known for occasionally defoliating maples and elms in urban areas, although they feed on a wide variety of both deciduous and coniferous tree species. This species produces at least two generations each year, with one generation over-wintering in the egg stage. The flight-less female moth actually lays a frothy mass of nearly 300 eggs on top of her old gray cocoon. Males are fairly plain looking with greyish wings with a mottling of wavy black lines and a white spot.

Other tussock moth caterpillars are found in the Triangle this time of year as well, including the Sycamore Tussock Moth (Halysidota harrisii, which my neighbor recently showed me), the Milkweed Tussock Moth (Euchaetes egle) and the Variable Tussock Moth (Dasychira vagans).

Did you know?

· Sycamore Tussock Moth caterpillars feed voraciously on sycamore leaves, with young larvae feeding close together.

· Milkweed Tussock Moth caterpillars acquire chemical defenses from milkweed and dogbane plants, which the adult moths retain.

· Many tussock moths have one generation per year in the northern United States and two in the south.


National Audobon Society. 1980. Field Guide to North American Insects and Spiders. New York, New York: Chanticleer Press.

Conant, R., and J.T. Collins. 1991. A Field Guide to Reptiles and Amphibians: Eastern and Central North America. Houghton Mifflin Company: Boston, MA.

Cook, Dave. 2001. The Piedmont Almanac. Chapel Hill, North Carolina: Mystic Crow Publishing.

Daniels, J. C. 2003. Butterflies of the Carolinas. Cambridge, MN: Adventure Publications, Inc.

Ehrlich, P., D. Dobkin, and D. Wheye (1988). The Birder's Handbook. New York: Simon & Schuster.

LeGrand, H. E. Jr. 2009. Notes on the Butterflies of North Carolina. Available at:

Palmer, W. M. and A. L. Braswell. 1995. Reptiles of North Carolina. Chapel Hill, NC: University of North Carolina Press.

Wagner, DM. 2005. Caterpillars of eastern North America. Princeton University Press.