White-breasted Nuthatch (Photos by Mary Holland)

A bird feeder serves as a gathering spot for the immediate community of seed-eating birds, and just as a small town's general store attracts an assortment of personalities, you can find all kinds of traits evident in the feathered visitors at a feeder. There are the bullying blue jays, the twinkle-eyed tufted titmice, the chipper chickadees, and the gluttonous grosbeaks, to name a few. Among my personal favorites are the natty nuthatches. Their name derives from their habit of taking seeds in the fall and winter and caching them in bark crevices, sapsucker holes, and even in the ground for later consumption.

One quick glance at a White- or Red-breasted nuthatch, and its dapper appearance is unmistakable. With their clean lines, compact bodies, and chisel-shaped, slightly upturned bills, nuthatches are one of the more sophisticated-looking birds that grace our feeders. Their appeal doesn't end with their appearance, however. It's their unusual foraging technique that often captures our attention first.

Unlike another insect-eating, tree-trunk-climbing bird, the Brown Creeper, which spirals up tree trunks gleaning insects, nuthatches often do the opposite—spiral downward. They can be observed moving quickly sideways and upward as well, with little regard for the direction in which they are going, particularly out on branches. But when you see them on the trunk of a tree, they are often descending head-down. Because of this, they are able to detect insects and insect eggs in bark crevices that would be hidden from view for most birds.

There are some fairly obvious differences, both physical and behavioral, between the White- and Red-breasted nuthatch. The White-breasted nuthatch is larger than the Red-breasted, and its plumage differs significantly, as the respective names denote. While I've experienced difficulty telling the calls of the two species apart, most birders can differentiate the nasal "yank-yank-yank" of the Red-breasted nuthatch, said to resemble the blast of a tiny tin trumpet, from the White-breasted nuthatch's six-to-eight notes that end with a slight rising inflection.

Red-breasted Nuthatch

Behaviorally speaking, with apologies to those adverse to anthropomorphism, the White-breasted nuthatch's personality appears to be much more staid than that of the Red-breasted nuthatch. Arthur C. Bent, an early-1900s ornithologist, wrote:

"The White-breasted nuthatch is a droll, earnest little bird, rather sedate and unemotional. He is no great musician and seems to lack a sense of humor. He has none of the irrepressible fidgetiness of the House Wren, none of the charming happiness of the Song Sparrow; he appears to take life on a matter-of-fact level."

In comparison, Red-breasted nuthatches appear far more sociable and more active than White-breasted nuthatches. Bent describes them as "so happy, animated, and lively … their voices have such a range of expression that they almost talk—a playful gathering of talkative, irrepressible, woodland gnomes."

While both of these species of nuthatches tend to associate with Black-capped Chickadees and Tufted Titmice in what are called "foraging flocks" in the winter, they generally are found in different habitats. The Red-breasted nuthatch has a preference for conifers, while the White-breasted nuthatch tends to nest in mature deciduous woods.

Both species of nuthatches build their nest in tree cavities; White-breasted nuthatches generally nest in an existing cavity, such as an old woodpecker hole, and Red-breasted nuthatches excavate their own cavity in a rotted stub or branch of a dead tree. All species of nuthatches perform some sort of nest entrance modification, but the nature of this modification differs with these two species. Red-breasted nuthatches actually smear the perimeter of their nesting hole with globules of fir, spruce or pine pitch, continually adding fresh pitch until their young are fledged. It is thought that this practice might prevent insects, small birds or mammals from entering the cavity (adult nuthatches have been observed flying directly into their nest cavity without touching the entrance's rim). White-breasted nuthatches engage in "bill sweeping" at the entrance to their nesting cavity, which consists of prolonged sweeping of their bill in a wide arc in or outside their cavity, often while holding an insect in their bill. One theory held is that the crushed insects may repel squirrels from taking over the cavity for their own nesting site.

With winter fast approaching, the prime time for observing nuthatch behavior is upon us. Every so often Red-breasted nuthatches appear in fairly large numbers at winter feeders, due to their southward movement, referred to as irruptions. When the coniferous seed crop is poor farther north, certain seed-eating birds, including Red-breasted nuthatches, seek food further south. Even if there's a good seed crop in Canada, however, Both Red-Breasted And White-breasted nuthatches, given the right habitat, should be plentiful and easy to watch and admire at Harvard feeders.

Mary (Richards) Holland will be at the Harvard Public Library Saturday, Dec. 4, at 1 p.m. to sign copies of her recently published book, Naturally Curious: A Photographic Field Guide and Month-by-Month Journey through the Fields, Woods, and Marshes of New England. The book is available at www.trafalgarbooks.com/NACU.html or at your favorite bookstore. You can read her natural history blog at www.naturallycuriouswithmaryholland.wordpress.com.