Friday, February 14, 2014

American Beech

“[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 NaturalHistory of Trees of Eastern and Central North America
Beech nut
The American Beech (Fagus grandifolia) is never more beautiful than in winter, with its slender branches outlined in ice, their downward sweep extended by stubborn leaves that refuse to fall. It's beauty has been noted by both eminent naturalists and giddy couples seeking to etch their love permanently into its smooth gray bark.

Found across eastern North America, west to Minnesota and south to Texas, the American Beech populates hardwood forest and well-drained bottomlands. It can be recognized by its alternate, elliptical leaf with sharply incurved teeth, its lancelike pseudoterminal buds, and its small nut encased by a prickly husk. 

Two varieties of American Beech are known to occur in North Carolina. Fagus grandifolia var. caroliniana occurs in the Piedmont and Coastal Plain, and it is recognized by the fuzzy hairs on the underside of its thin leafFagus grandifolia var. grandifolia occurs in the mountains and is hairyless or hairy only on the midveins of the leaf. 

Scorias spongiosa on Beech in Durham NC
In many forests of the Piedmont, the beauty of the American Beech is marred only by the Beech Blight Aphid and the dense black fungus (Scorias spongiosa) that grows on the aphids' honeydew. Yet, with dense snow covering the ground and base of the trunk, even this cannot detract from the grace of the American Beech.

Thursday, February 13, 2014

What is the coldest environment birds can tolerate?

A Triangle Naturalist reader recently asked: "Is there a temperature limit past which birds can no longer withstand the elements?"

While many bird species migrate to avoid to the chill of winter in temperate climates, some species, like the Emperor Penguin live year-round in frigid Antarctica, where temperatures can dip below -76°F and winds roar at 100 mph.

Emperor Penguins maintain their body temperature through a number of adaptations. While cozying up en masse, Emperor Penguins also rely on their specialized circulatory system, a thick layer of blubber, and densely packed feathers to stay warm.

Emperor penguin huddle
Emperor Penguins huddle to stay warm. Photo from Warner Bros at

Birds in the Piedmont of North Carolina, and the upper Midwest, stay warm using similar adaptations. Some species will huddle together, with the birds at the end regularly switching places with the birds in the toasty middle. Ducks and gulls, for example, have specialized circulatory systems in their feet allowing for counter-current exchange, where warm blood leaving the body heats up the cold blood coming back into the body from feet sitting in icy water. Downy feathers also provide insulation against severe cold.

To return to our reader's question -- is there a temperature limit past which birds won't survive? -- my reply is that there must be, but of all the vertebrate taxa in the world, birds have managed to endure cold the most successfully.

Wednesday, February 12, 2014

Where do birds go when it snows?

On days like this, when the snow drifts down steadily in large, dense clumps, where do all the birds go?

Many birds species spend the winter in the Piedmont of North Carolina. Some species, like Carolina Chickadees and Tufted Titmice, spend their time in mixed foraging flocks, searching for food sources as a group. Other species, like the American Robin, will spend their time in groups of their own species.

During inclement weather, like a snow storm, most birds will huddle in the crevice of a tree branch, trying to find shelter from the cold and wet. Some species will hang tight to the trunk of a tree. Yellow-Bellied Sapsuckers use their special, zygodactyl feel (i.e., 2 toes facing forward, 2 toes facing back) and stiff tail feathers to brace themselves tight again a large pine or hardwood.

In this photo, naturalist Will Cook has perfectly captured the zygodactyl feet of the Yellow-Bellied Sapsucker. If you'd like to see more of Will Cook's fantastic photos, visit his website at

If the birds are hungry enough, they will come out of their relatively warm resting spots for a high quality food source, like the shriveling fruits of the beauty berry bush or seed offered by a bird-loving homeowner.