Tuesday, September 1, 2009

GREAT EXPECTATIONS: September in the Piedmont


Birds.− September brings a number of winter residents back to the Piedmont, including the yellow-bellied sapsuckers, an occasional red-breasted nuthatch and a number of wrens (winter, sedge, marsh) and sparrows (swamp and white-throated). Migrant warblers continue to pass through North Carolina as they head towards the neotropics for the winter. Birders may even see snowy egrets, little blue herons and tricolored herons, which won’t return again to the Piedmont until early April.

The ruby-crowned kinglet (Regulus calendula), a diminutive songbird first described by Linnaeus in 1766, returns to the Piedmont this month after spending the summer in their breeding habitat, the coniferous forests of Canada and the northern United States. These tiny olive-grey birds, with thin dark bills, are named for the bright red spot on the top of the head of males of this species. They can also be identified by their chirp-like “di-dit” call and their constant wing-flicking. They usually forage for small insects and spiders in trees, but will sometimes take berries and tree sap.

Butterflies.− Expect to see a pulse of cloudless sulphurs, little yellows and sleepy oranges this month. Swallowtail sightings will likely drop-off by mid-month, with the exception of the black swallowtail. Butterfly watchers can also expect to see gray and red-banded hairstreaks, gulf and variegated fritillaries, as well as an increased number of viceroy sightings. Monarchs may be seen as they migrate southward to their winter residence in Mexico.

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 sulphurs (subfamily: Coliadinae), some species of which are on the rise this month. Members of the Coliadinae are normally some shade of yellow, often having dark markings on their wings. Males and females usually differ in appearance (i.e., they are sexually dimorphic), and their coloration may vary with the seasons. For example, the sleepy orange if often bright yellow in the summer, but their hindwings often become rust-colored in the fall. Male sulphurs can often be found congregating around mud-puddles, where they obtain water and salts. Sulphurs are found in open, disturbed habitat and they over-winter as larvae.

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

Other Insects.− This month, expect an increase in praying mantis and spider activity. Female garden spiders (Argiope aurantia) will be guarding egg cases this time of year. In fact, garden spiders breed only once a year. Males garden spiders will court the females by plucking strands on her web, and die after mating, sometimes being consumed by the female. The female garden spider will then lay her eggs (usually at night), covering them in layers of silk. One to four egg sacs, with thousands of eggs inside, are usually suspended in the middle of her web, where she guards them against predation until she dies with the first hard frost. In spring, young garden spiders will emerge from the brown-silk sac. Some offspring may remain closeby, but others exude a strand of silk that gets caught in the wind, carrying them to a new home.

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

In Bloom:
WINGSTEM – Actinomeris alternifolia
WHITE SNAKEROOT – Ageratina altissima
PARTRIDGE PEA – Chamaechrista fasciculata
TURTLEHEAD – Chelone glabra
BEECHDROPS – Epifagus virginiana
DEVIL'S-GRANDMOTHER - Elephantopus tomentosus
BONESET – Eupatorium perfoliatum
BLACK-EYED SUSAN – Rudbeckia sp.
TRAILING WILD BEAN - Strophostyles helvula
GREAT LOBELIA – Lobelia siphilitica
DOWNY LOBELIA – Lobelia puberula
SMALL SKULLCAP – Scutellaria parvula
AXILLARY GOLDENROD – Solidago caesia
GOLDENROD(S) – Solidago spp.

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

Historical Anecdote: Sweet gum – Liquidambar styraciflua
“This sweet gum is a noble tree, that might well impress anyone new to the sight of it. And the sight is a common one, for it grows along any fence row, in piedmont Virginia, beside any country road of the Carolinas, in any field abandoned by agriculture and growing up to scrub pine and dogwood. It comes up in company, in these upland sites, with sassafras and red cedar, and may be known by its beautiful star-shaped leaves. Their upper surface has a star-like glister, but unlike most shining leaves, those of the sweet gum are not dark at maturity but a light, gay yellow-green. Crushed in the fingers, they give out a cleanly fragrance; on the tongue they have a tart taste. Foliage so odd and yet so attractive would make any tree conspicuous.” – Donald Culross Peattie, 1948, A Natural History of Trees of Eastern and Central North America

Wildlife Profile.− This month’s wildlife profile is the CAROLINA MANTIS (Stagmomantis carolina), the only praying mantis native to North Carolina. North Carolina is also home to the Chinese mantis (Tenodera sinensis), which was introduced as pest control in the 1890s. The Carolina mantis is distinguished from the Chinese mantis by its small size, reaching only 6 cm in length. Additionally, Carolina mantids are pale green to brownish gray, and their wings do not extend past their abdomen. Whereas, the Chinese mantis can reach up to 8.5 cm and their wings are tan with green front margins. The European mantis, introduced to the northeastern United States from southern Europe in 1899), also occurs in Durham County, but is much more rare. The European mantis is small, like the Carolina mantis, but its wings extend beyond its abdomen.

Both Carolina mantids, as well as Chinese and European mantids, can be observed mating in September. After mating, the female Carolina mantis often devours her mate. She will lay 30 to 80 eggs, coated with a frothy tan water-repellant material that hardens, onto a plant stem. Carolina mantids show a marked preference for goldenrod. In spring, nymphs, looking like tiny mantids, will appear and begin hunting. Carolina mantids prey voraciously upon butterflies, moths, wasps, bees and other insects.

Carolina mantids are found from Virginia, south to Florida, westward to California.

Did you know?
• Carolina mantids overwinter as eggs.
• Female Carolina mantids eat their mate approximately 25% of the time.
• Carolina mantis egg cases are oval and flat along the twig against which they are laid; Chinese mantis egg cases are round; European mantis eggs cases are round but flattened on one side.
• Female mantids often return to the place of their birth to lay eggs.
• Carolina mantids are beneficial insects, preying on agricultural pests.

National Audobon Society. 1980. Field Guide to North American Insects and Spiders. New York, New York: Chanticleer Press.
Cook, Dave. 2001. The Piedmont Almanac. Chapel Hill, North Carolina: Mystic Crow Publishing.

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