A cavity in an old apple trunk outside my window is being visited minute-by-minute by a pair of white-breasted nuthatches. Less frequently, they are joined by their red-breasted cousins.
Nuthatches run head-down over bark, spiraling and zigzagging around a tree trunk. A moment ago, a white-breasted scooted down the apple’s trunk and, with an acrobatic flip, turned and dashed back upward. The nuthatch design includes 15 species throughout North America, Europe, and much of Asia. All resemble one another in appearance and behavior, with a short tail, dark body, and often a white eye stripe.
Nuthatches use long, sharp bills to probe beneath bark and into crevices searching for insects and spiders. If small creatures are scarce, nuthatches attend bird feeders, competing with chickadees. I counted one nuthatch arriving at a seed dispenser for every seven chickadees.
Both nuthatch species prefer oil-rich seeds, so the level of sunflower seeds in a feeder drops visibly within an hour. Because a nuthatch lacks a crushing bill, it removes a seed, flies to a nearby tree, jams it into a crack in the bark, and then hammers it open to get the rich meat inside. It is this trick that gave the little bird its name, “nut-hack.” When I’m out filling a feeder, white-breasteds perch within hand-reach, calling a soft, impatient “yank-yank.” As I turn away, they dash in, beating the abundant chickadees by inches, snatch a seed, and fly to a nearby maple.
Red-breasted nuthatches, birds of the North and less common around our feeders, seem less dependent upon a rich seed supply. They call with a high pitched “yna-yna” from a safer distance. After taking a seed, one flies off into the forest, where woodland pine nuts are just as welcome.
Nuthatches are no dummies when it comes to surviving winter nights – they retreat to cozy holes instead of fluffing feathers and huddling close to a tree trunk in deep woods as other birds must. The opening in our old apple trunk faces obliquely downward, so it drains, remains dry, and is deep enough to shield against the wind. Whichever nuthatch enters for the last time at dusk, it remains through the night. Somewhere nearby another comfortable hole is occupied by its sleeping partner.
During a recent blustery day, our white-breasteds took turns coming to the tree, perching on the hole’s rim, wiping bills, looking inside, and then one at a time disappearing into the interior. They weren’t carrying food, just going inside out of the weather. In a minute or so, a warmed-up bird would emerge and pause briefly on the rim as it dropped waste from interior housecleaning before flying away. Its mate followed the same procedure. Even if both members of a pair remain nearby, only one nuthatch at a time occupies a hole.
Nuthatches nest in protected tree holes away from adverse elements. Woodpecker-like, they enlarge and shape a hole to suit, smoothing the rough interior with wood chips and bits of moss. A red-breasted nuthatch may excavate a completely new cavity in rotten wood.
Bill-wiping on the rim of a hole is mystifying. Occasionally I find a wisp of dog hair lodged there from a white-breasted’s activity. Red-breasteds may smear pitch from evergreens around the entrance. It’s not clear what the purpose is, although some say animal hair and conifer sap impart odor and texture to the wood that squirrels and predatory mammals find offensive. Sticky pitch I understand, but nuthatches aren’t supposed to have a sense of smell, so how do they know if my dog’s hair stinks?
Bill-wiping could be a vestige of behavior from nuthatches in other parts of the world. Elsewhere, some species plaster the opening with mud to deny access to predators and larger birds so that only nesting occupants can enter. Other nuthatches obstruct the opening with plant fiber and bits of bark, but our North American species only wipe bills, leaving traces of substances on the rims.
The lack of interaction between nuthatch species puzzles me. Sometimes when the white-breasted nuthatches are away from the hole I think is theirs by eminent domain, a pair of smaller red-breasteds adopts the same pattern of flying to the rim, looking about, hopping in, staying a while, and then leaving. I’ve never seen competition between the two species, so maybe they simply respect an alternating priority. I’ll watch to see who claims the cavity for nesting.
I don’t know how far generosity of spirit persists, however, because I haven’t determined which species enters for a snug night’s sleep. Is it consistent? Perhaps they follow a first-come, first-served arrangement. Vermont and New Hampshire winters being what they are, and liking a warm bed, I’d arrive good and early.