GREAT EXPECTATIONS: April in the Piedmont

Birds.− This month, spring migrants are headed our way. Some species that may be seen during the next couple months, as they head north, include: some wood-warblers (including golden-winged, Nashville, chestnut-sided, magnolia, black-throated blue, black-throated green, bay-breasted and blackpoll), herons (e.g., little blue heron, black-crowned night heron, cattle-egret), thrushes (e.g., veery, grey-cheeked and Swainson’s) and sandpipers (e.g., spotted and solitary). Also be on the lookout for sora, Virginia rail or a rare glossy ibis.

Species will be arriving this month with the intention of staying the summer and breeding here in the Piedmont; these include: whip-poor-wills, chimney swifts, ruby-throated hummingbirds, eastern wood-pewees, Acadian flycatchers, eastern kingbirds, northern parulas, prairie warblers, summer and scarlet tanagers, and yellow-breasted chats.

Some of our year-round residents are busy this month as well. Many Carolina wrens – small, energetic brown birds with upturned tails, distinct whitish eyebrows and curved bills -- hatch in April, and the young are heard boldly chirping in their nests. The female usually incubates five eggs in a nest of twigs, bark, leaves and grass busily constructed by both parents. Nest sites often can by found in cavities and protected areas, both natural and man-made. Unused grills and back porches are often prime real estate for these adaptable birds. After two weeks of incubation, young Carolina wrens hatch and noisily demand food from both parents. Carolina wrens live approximately six years and mate for life.

Did you know? The spring migration of birds occurs along four principal “flyways” in North America. Lucky for us, the Atlantic flyway crosses North Carolina, and provides a route northward from Central America and the West Indies for about 150 species of migratory birds. Ample food and cover exist along the entire mountain-free flyway, which stretches from the Gulf of Mexico, through the Carolinas and Virginia to the northeastern states and into central Canada.

Butterflies.− In April, butterfly watchers may begin to find some of the skippers (e.g., zabulon, dusted, pepper and salt), duskywings (mottled, zarucco), cloudywings (southern, northern, confused), satyrs (gemmed, Carolina) and pearlyeyes (southern and northern). Silvery checkerspots can be spotted in moist floodplains or sometimes near drier woodland borders, where adults glean nectar from, and caterpillars feed, on sunflowers (Helianthus) and rosinweeds (Silphium spp.). Look for red-spotted purples in hardwoods forests and forest edges; adults may be found taking sustenance from tree sap or damp ground, while caterpillars feed on cherries (Prunus spp.) and other members of the Rosaceae. Butterfly aficionados will continue to see a number of sulphurs and hairstreaks this month, as well as questionmarks and commas. The most spectacular visitors, this month, may be the monarchs and their mimics, viceroys.

Swallowtails, a largely tropical family of colorful butterflies with distinctive tails on their hind wings, make exciting sightings in April. Five swallowtail species make their homes in Durham County: the Spicebush Swallowtail, Pipevine Swallowtail, Black Swallowtail, Zebra Swallowtail, and the Eastern Tiger Swallowtail. The Eastern Tiger Swallowtail is also the state butterflies of Delaware, Georgia, South Carolina, and Virginia. Swallowtails typically use as a wide variety of flowers as nectar plants, and the caterpillars of some species can be quite particular. For example, the Pipevine Swallowtail caterpillars feed exclusively on Aristolochia species, including the native Dutchman's pipe (Aristolochia durior) and Virginia snakeroot (Aristolochia serpentaria). The Zebra Swallowtail caterpillars strictly rely on the two pawpaws species native to North Carolina, tall pawpaw (Asimina triloba) and dwarf pawpaw (Asimina parviflora) as foodplants.

Other Insects.− This month, field crickets will begin to call, crane flies will hover in the grass and ticks abound. Also expect to see some dragonflies zipping through the air, searching for mosquitoes and other prey. Dragonflies to look for in April include the darners, a family that represents some of the largest and fastest flying dragonflies in North America. Species sighted in Durham County include the Common Green Darner, Springtime Darner, and Swamp Darner. The Common Green Darner – a three inch long green dragonfly with a brown and yellow (females) or bluish (males) abdomen -- probably is active longer than any other Dragonfly species in the state: it can be seen in the Piedmont from March through October cruising over open habitat, especially near still water.

Reptiles & Amphibians.− This month, northern cricket frogs, eastern narrow-mouthed toads and Cope’s gray treefrogs will begin to call. American and Fowler’s toads, spring peepers, bull frogs, green frogs, southern leopard frogs and eastern spadefoots will continue to call, but the large choruses of southeastern chorus frogs will be winding down this month.

April frog call guide:

southeastern chorus frog: raspy, rising call like someone dragging their thumb over the teeth of a comb

spring peepers: a loud, medium pitched “peeep”

northern cricket frogs: clinking like two small metal balls being tapped together

American toads: long, musical trill

Fowler’s toads: long, slightly nasal, crabby trill

eastern narrow-mouth toads: buzzy and sheep-like call (like a Fowler’s toad, but shorter and buzzier)

eastern spadefoot toads: a crabby, deep “eeeerrrr”

Look in shallow permanent or ephemeral ponds to find frog and toad eggs and even tadpoles. In April, visible eggs include the long gray-green strings of Fowler’s toad eggs and globs of gelatinous black spotted Cope’s gray treefrog eggs. In most years, small and dark American toad tadpoles will emerge this month.

Also, be on the lookout for basking yellow-bellied sliders and painted turtles. Snakes will be out as well, so be sure not to step on the diminutive and well-camouflaged northern brown snake (Storeria dekayi) when walking on preserve trails. When gardening this month, also watch out for secretive rough earth snakes and eastern worm snakes, North Carolina’s most common snake species.

In Bloom this Month.− April is a wonderful month to test your tree identification skills. Try to identify trees by their bark or buds before they flower and leaf out!

In late March and early April, woodland hikers may notice a diminutive plant with three mottled leaves radiating out from the center, topped by a single maroon flower; this is likely one of the Piedmont’s most common trilliums, little sweet betsy or Trillium cuneatum. This musk-scented gem was once used medicinally to treat gangrene and skin ulcers. It is now a favorite among natural landscapers, as it is deer resistant.

In Bloom:

BUCKEYES (Aesculus spp.)

WINDFLOWER (Anemonella thalictroides)

SWEET-SHRUB (Calycanthus floridus)

MUSCLEWOOD (Carpinus caroliniana)

FLOWERING DOGWOOD (Cornus florida)

RATTLESNAKE-WEED (Hieracium venosum)

QUAKER-LADIES (Houstonia caerulea)

EASTERN YELLOW STAR-GRASS (Hypoxis hirsuta)

DWARF CRESTED IRIS (Iris cristata)

CORAL HONEYSUCKLE (Lonicera sempervirens)

HAIRY WOODRUSH (Luzula echinata)

VIRGINIA PENNYWORT (Obolaria virginiana)

MAY-APPLE (Podophyllum peltatum)

EARLY SAXIFRAGE (Saxifraga virgininiensis)

AMERICAN BLADDERNUT (Staphylea trifolia)

GIANT CHICKWEED (Stellaria pubera)

FOAMFLOWER (Tiarella cordifolia)

CATESBY’S TRILLIUM (Trillium catesbaei)

LITTLE SWEET BETSY (Trillium cuneatum)

MAPLE-LEAF VIBURNUM (Viburnum acerifolium)

DOWNY ARROW-WOOD (Viburnum rafinesquianum)

Soil Series of the Month.− Recall that the United States contains over 19,000 different soils series, i.e., the most specific grouping of soils based on shared history, chemistry, and physical properties. The most general classification of soil is the soil order. Worldwide, there are only 12 soil orders. North Carolina is home to seven: Entisols, Inceptisols, Alfisols, Ultisols, Mollisols, and Spodosols.

A common Ultisol, the quintessential deep red, clayey soil of the Piedmont, in this area is the Mayodan soil series. Mayodan soil is light gray or yellow-brown in the top six to twelve inches, and then becomes yellowish-red as depth increase. It is typically weathered from Triassic sediment (think: shales, sandstones, mudstones formed from erosion nearly 200 million years ago) in the uplands of the Piedmont and naturally supports oak-hickory forests. Over half of the acreage of Mayodan soil now support agricultural crops, especially corn, soybeans, tobacco, and cotton.

Wildlife Profile.− This month’s wildlife feature is the NORTHERN PARULA (Parula americana), a colorful warbler that migrates to the Piedmont in spring and breeds locally. Northern Parulas are small songbirds with blue-gray heads and wings, yellow throats, and a chest banded with black, red, and bright yellow. They also sport white crescents above and below each eye and two white wing bars.

Each spring, Northern Parulas arrive mostly from the Caribbean, although they also winter in Mexico, Guatemala, and Belize. Once in the Piedmont, these insectivorous birds move quickly, gleaning leaves and branches high in the canopy, although sometimes they can be seen at eye-level. Since they are difficult to find so high in the trees, North Parulas are often identified by their buzzy, ascending call that end in a distinct, sharp down note. They typically breed in bottomland forests and they make tiny nests of lichen (or Spanish moss further south) high in the canopy of oaks, maples, birches, and sycamores near the tips of branches. Nests are built quickly, in only a few days, and the same nest site may be used year after year. Only two weeks after laying speckled, creamy white eggs, helpless and unseeing young hatch.

Northern Parula populations appear to be stable or even increasing, but an unusual break occurs in their distribution between the north and south. Ornithologists have suggested that this break may be due to habitat change or to air pollution. Air pollution often kills vulnerable lichen species, which are an important nesting material for Northern Parulas.

References:

Cook, D. 2001. The Piedmont Almanac. Raleigh, NC: Barefoot Press.

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: http://149.168.1.196/nbnc/

LeGrand, H. E. Jr. and Howard, T. E. Jr. 2011. Notes on the Odonates of North Carolina. 3^rd Approximation.

Martof, B. S., W. M. Palmer, J. R. Bailey, and J. R. Harrison. 1980. Amphibians and Reptiles of the Carolinas and Virginia. The University of North Carolina Press: Chapel Hill, NC.

Moldenhauer, R. R., and D. J. Regelski. 1996. Northern Parula (Parula americana). In The Birds of North America, No. 215 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.