On the Wild Side

Trees as Habitat. - This month, take a look at all those trees that are beginning to flower and leaf out. These trees provide habitat for many animals.

For example, tree hollows or semi-enclosed natural cavities in the trunks of trees, can be used as diurnal (daytime) or nocturnal (nighttime) shelter sites for animals. They can also be used to rear young, to feed, and for thermoregulation. For example, in holes high up in the tree, you might find chickadees. Chickadees will go into a hole, puff out their feathers, go into a state of hypothermia with body temperatures of about 20 degrees F, and wait out the cold weather.

Image of a habitat tree showing various features
Image from Arboriculture International

The bark of a tree is also habitat for animals. In fact, five species of bat in the Piedmont roost in trees: the Seminole bat (year-round resident), the silver-haired and hoary bats (winter residents), and the red and evening bats (summer residents). Bark can also provide habitat for insects and spiders, including the broad-faced sac spider, funnel-web spiders, and lynx spiders lying in wait to catch their prey.

Tip-up-mounds (or mounds formed when a large tree is uprooted) can also provide unusual animal habitats. For example, amphibians can breed in the holes left behind by the dispossessed root ball. Tip-up-mounds also provide habitat for small mammals and ground nesting birds. Winter wrens, a winter resident in the Piedmont, have been known to nest in tree roots at their summer grounds.

Finally, the stabilizing nature of tree roots means that animals can often burrow under trees. In fact, squirrels are usually seen at their day nests high in trees, but they prefer to nest in tree holes at the base or beneath trees. These holes are usually two to four inches in diameter. Chipmunks, too, will nest in burrows beneath trees, storing up to 10 quarts of nuts, berries, and other goodies in their winter den.

Birds. - Many bird species will be migrating this month. Migration is different from other types of avian movements because it is “seasonal, predictable, and repeated each year *”. Other types of avian movements lack these qualities. For example, some species fly long distances to forage – or search for food – but their foraging is not seasonal. Other species move to new sites after they hatch – this is called dispersal. Since an individual bird does not disperse each year, this is not migration either.

Approximately five species of wood-warblers (Family: Parulidae) pass through the Triangle in March, ending their journeys further north, including the blue-winged, Tennessee, orange-crowned, yellow, and black-throated green warblers. Other species of wood-warblers will arrive this month and stay to breed, including the northern parula, black-and-white warbler, American redstart, prothonotary warbler, worm-eating warbler, ovenbird, and Louisiana waterthrush.

Head shots of 11 Eastern Wood Warblers
Image from Bur Oak Botanicals Blogger

By the end of the month, you may see both male and female woodpeckers excavating their nests (although the males often do most of the work). Woodpeckers usually excavate a new nest cavity each year, while starlings, sparrows, and titmice quickly appropriate old, empty cavities. Although the trees that woodpeckers excavate may look alive, research has revealed that most woodpecker species chose to excavate trees with dead heartwood. One exception, found in the North Carolina sandhills, is the red-cockaded woodpecker, which prefers to dig into live pine trees.

If you look carefully up at the holes that woodpeckers make, you can identify the species. For example, pileated woodpeckers excavate holes that are rectangular and often several feet long. In contrast, the downy woodpecker may have a hole that is only a half-inch in diameter.

* Elphick et al. 2009, p59

Butterflies. - This month, butterfly watchers may begin to find hairstreaks (including the red-banded, gray, juniper, and great purple) and swallowtails (e.g., black and eastern tiger). If you want to find zebra swallowtails, be sure to look in the right sort of habitat: breeding takes place in rich, moist woodlands often near rivers and swamplands. In fact, zebra swallowtail larvae will only feed on paw-paw (Asimina species.), although adults may fly out to the forest edge to enjoy nectar from a variety of sources including milkweeds (Asclepias species) and the eastern redbud (Cercis canadensis).

Reptiles & Amphibians. - Throughout March, expect to hear Southeastern chorus frogs, Northern cricket frogs, American toads, pickerel frogs, and Eastern spadefoots. Fowler’s toads, bullfrogs, and green frogs will start calling this month, but do not expect large choruses until April.

Also, expect to hear the exuberant harbingers of spring: spring peepers (Pseudacris crucifer). These small, copper-colored frogs, with a dark X across its back, announce spring with loud peeps. Armies of peepers – the proper name for a group -- can be heard as far as 2.5 miles away.

Found throughout North Carolina, spring peepers prefer woodlands with ample forest litter and breed in ponds, swamps, and ditches. The female spring peeper lays about 900 eggs per complement, attaching each egg singly to submerged wood and vegetation. In a few days, the eggs hatch, releasing impossibly small, dark tadpoles into the water. After three or four months, the tadpoles metamorphose into adult peepers

Adult spring peepers are carnivorous, preying upon worms and small arthropods. In most areas, they are nocturnal hunters, but in humid environments, they also hunt during the day. Adults are vulnerable to predation from spiders and birds and, in some areas, spring peeper populations are declining due to habitat loss.

March 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
  • pickerel frogs: drawn out snore
  • Eastern spadefoot toads: a crabby, deep “eeeerrrr”

In Bloom

In Bloom this Month. - March is a great month to brush-up on your herbaceous plant identification, starting with the spring ephemerals – fragile wildflowers that disappear after a brief vernal resurgence.

One of the first flowers to bloom in March is round-lobed hepatica (Hepatica americana). Other March ephemerals include the spring beauty (Claytonia virginica) and trout lilies (Erythronium americanum) with their yellow nodding flowers emerging from a pair of dark green, spotted leaves. If you are exploring richer woods, you might find red trillium (Trillium cuneatum), may-apples (Podophyllum peltatum), a few species of wild ginger or heartleaf (Hexastylus spp.) and bloodroot (Sanguinaria canadensis).

Photograph of early spring Bloodroot
(Photo provided by N. Cagle)

Bloodroots are fascinating plants with clasping, multi-lobed dark green leaves from which emerge a delicate 8-12 petaled white flower. Small bees and flies pollinate its flowers, and ants disperse its seeds in a process known as myrmecochory. The ants are attracted to a fleshy, edible organ on the seed known as an elaiosome. Ants bring the seed back to their nest, where they eat the elaiosome, and then deposit the seed in their fertile nest debris!

In Bloom:

  • RED MAPLE (Acer rubrum)
  • WINDFLOWER (Anemonella thalictroides)
  • CUT-LEAF TOOTHWORT (Cardamine concatenate)
  • EASTERN SPRING-BEAUTY (Claytonia virginica)
  • EASTERN REDBUD (Cercis canadensis)
  • AMERICAN HAZELNUT (Corylus americana)
  • AMERICAN TROUT-LILY (Erythronium americanum)
  • ROUND-LOBED HEPATICA (Hepatica americana)
  • LITTLE HEARTLEAF (Hexastylis minor)
  • QUAKER-LADIES (Houstonia caerulea)
  • SMOOTH NORTHERN SPICEBUSH (Lindera benzoin)
  • HAIRY WOOD-RUSH (Luzula acuminata)
  • MAY APPLE (Podophyllum peltatum)
  • BLOODROOT (Sanguinaria canadensis)
  • GIANT CHICKWEED (Stellaria pubera)
  • RED TRILLIUM (Trillium cuneatum)
  • DOORYARD VIOLET (Viola sororia)

Wildlife Profile

Photograph of four-toed slamander
(Image from SREL Herpetology)

In North Carolina, the Wildlife Resource Commission has listed the four-toed salamander (Hemidactylium scutatum) as a species of special concern. Although some populations have been found in the Coastal Plain and Mountains, the four-toed salamander predominantly occurs in the Piedmont, where it prefers marshes, swamps, and ephemeral ponds surrounded by forest.

After mating in the fall, some female four-toed salamanders cooperate with each other during the spring nesting season, preferring to lay eggs together on moss-covered logs and roots draped over still water. This communal nest allows one female to leave for a short period, while the other stays behind to tend to the eggs. While it may look like the females are guarding the eggs from predators, researchers have suggested that the females protect the eggs from egg-destroying fungus. Reid Harris and Douglas Gill have suggested that female four-toed salamanders may even eat fungus-infected eggs (1, 2).

After one and a half to two months of protection, in the warmth of early summer, the larvae finally emerge from the eggs and drop into the still water where they transform into small adults in about 6 weeks. It takes at least one and half more years for the young four-toed salamanders to reach sexual maturity (2). Rocks and leaf litter typically provide habitat for these adults.

As adults, the four-toed salamanders range from 2 to 3.5 inches. Small, black spots speckle their mottled, reddish-brown backs, and their tail shows the brightest red. That tail, if grabbed, can disconnect from the body and will continue to writhe and wiggle to lure predators away from the feeling salamander. The belly of the four-toed salamander is white with black spots, and as its name suggests, the four-toed salamander only has four toes on each hind foot.

References

  • k, D. 2001. The Piedmont Almanac. Chapel Hill, NC: Mystic Crow Publishing.
  • (*) Elphick, C., Dunning, John B., JR., Sibley, D.A. 2009. The Sibley Guide to Bird Life and Behavior. Alfred A. Knopf, Inc. 588pp.
  • (1) Harris, R. N. and Gill, D. E. 1980. Communal nesting, brooding behavior, and embryonic survival of the four-toed salamander Hemidactylium scutatum. Herpetologica 36(2): 141-144.
  • LeGrand, H. E. Jr. 2009. Notes on the Butterflies of North Carolina. Available at: www.dpr.ncparks.gov/nbnc/
  • 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.
  • (2) Meyer, Rachelle. 2008. Hemidactylium scutatum. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: www.feis-crs.org/feis/ [Last accessed 13 Jan 2015].
  • National Geographic Society. Spring Peeper Profile. Available at: animals.nationalgeographic.com/animals/amphibians/spring-peeper.html [Last accessed 27 Feb 2011].

About the Author

Nicolette Cagle, Ph.D. is a passionate ecologist and environmental educator on the faculty of the Nicholas School of the Environment at Duke Univ

To learn more, please visit her website.