Monday, October 4, 2010

Flat River Impoundment (Durham, NC)

This past weekend, I brought my family to a Lepidopteran wonderland: the Flat River Waterfowl Impoundment in north Durham county, North Carolina.

Variegated Fritillaries, Flat River Impoundment, NC (photo by M. Cagle)

Butterflies (Order: Lepidoptera) abound at the small, goldenrod rimmed wetland, originally created to mitigate the loss of bird habitat after the Neuse River was dammed to form Falls Lake. Recent sightings by Rougement resident, Randy Emmitt, include scores of Variegated Fritillaries, Pearl Crescents, Common Buckeyes, and Common Checkered Skippers. Our own expedition also yielded a number of migrating Monarchs, Cloudless Sulphurs and a Variegated Fritillary caterpillar feeding happily on a passionflower vine.

Variegated Fritillary caterpillar, Flat River Impoundment, NC (photo by M. Cagle)

Our favorite location at the impoundment was "the butterly tree" -- a large willow loaded with Buckeyes, Viceroys, as well as some Question Marks, Red Admirals, and Red-Spotted Purples. Butterflies often congregate on willows to lay eggs (e.g., Viceroys and Red-Spotted Purples) and to glean sap (e.g., Question Marks and Red Admirals). We were also lucky to see a number of Great Egrets and a low-flying, white-rumped Northern Harrier (aka: Marsh Hawk).

The butterfly tree, Flat River Impoundment, NC (photo by N. Cagle)
Common buckeye butterfly, Flat River Impoundment, NC (photo by N. Cagle)

Great egrets, Flat River Impoundment, NC (photo by N. Cagle)

Warning: Make sure to visit on Sundays, when hunting is off limits at this popular fowling spot.

Sunday, October 3, 2010

GREAT EXPECTATIONS: October in the Piedmont

Birds.− October brings a number of winter residents back to the Piedmont, but also expect diminishing numbers of broadwing hawks, chimney swifts, most swallow species and ruby-throated hummingbirds. Migrant warblers continue to pass through North Carolina as they head towards the neotropics for the winter; they can often be found with vocal winter residents such as Carolina chickadees and tufted titmice.

The tufted titmouse (Baeolophus bicolor), an active and expressive songbird in the tit and chickadee family (Paridae), is a common resident of the eastern United States. This chatty bird demands attention as it darts through trees, searching for insects and caterpillars in spring and summer, and nuts and berries in winter and fall. In fact, titmice will often hoard food from bird feeders in winter and fall, usually stashing their stores within 130 feet of the source. Tufted titmice nest in the cavities left behind by woodpeckers and favor deciduous or mixed forest and suburban yards. Birdwatchers recognize the tufted titmouse by its prominent gray crest and dark eyes.

Butterflies.− Butterfly watchers can expect a decline in butterfly sightings this month, with the exception of some of the sulphurs and whites (family: Pieridae). Monarchs continue to migrate southward this month to their winter residence in Mexico.

Remember: The Carolinas are home to five families of butterflies: the skippers (Hesperiidae), gossamer wings (Lycaenidae), brush-foots (Nymphalidae), swallowtails (Papilionidae) and the sulphurs and whites (Pieridae). Each of these families can be divided into a number of sub-families, each having distinct identifying characteristics.

This month, we will consider the spread-wing skippers (subfamily: Pyrginae). Members of the Pyrginae are normally plain and dark brown or black, and some have light spots on their forewings. A number of species land with their wings open or half open. Female pyrgines take nectar from flowers, and males often obtain salts from mud-puddles and animal droppings. Caterpillars in the subfamily Pyrginae often live in shelters constructed of rolled or webbed leaves. Most pyrgines are found in the neotropics, but a number of species can be found in North Carolina, including Hayhurst’s scallopwing, dreamy duskywings (mountains only), southern cloudywings, mottled cloudywings and northern cloudywings. Larval hosts include birches, bush clovers, lamb’s quarters, milk vetch, New Jersey tea, poplars and willows.

Reptiles & Amphibians.− Continue to keep an eye out for snakes and turtles. Although you may still hear frogs and toads calling this month, large choruses won’t start up again until January.

Other Insects.− This month, 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. Also, expect a decline in spider sightings, but keep an eye open for garden spider and praying mantis egg cases. Also, dragonfly numbers are declining this month, although you may see some species migrating to winter territories.

In Bloom this Month.− Be on the lookout for some striking October flowers:

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.
IRONWEED(S) - Vernonia spp

In Fruit:
HEARTS-A-BUSTIN’ – Euonymus americanus
MUSCADINES – Vitis rotundifolia

Historical Anecdote: American Beech – Fagus grandifolia
“[The] Beech is identifiable by the gleam of its wondrously smooth bark, not furrowed even by extreme old age. Here it will be free of branches for full half its height, the sturdy boughs then gracefully down-sweeping. The gray bole has a further beauty in the way it flutes out at the base into strong feet, to the shallow, wide-spreading roots. And the luxuriant growth of mosses on the north side of such a tree, together with the mottling of lichens, add to the look it ears of wisdom and serenity.” – Donald Culross Peattie, 1948, A Natural History of Trees of Eastern and Central North America

Additional References:
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.