Last winter I spent hours in our Norway spruce grove watching red-breasted nuthatches. I first saw them on October 28 when one foraged on a Norway spruce tree trunk while another rushed around on the ground in search of Norway spruce nuts.
I had already learned from Doug Gross, Endangered and Non-game Bird Section Supervisor for the Pennsylvania Game Commission, writing in the October edition of PSO Pileated (the newsletter of the Pennsylvania Society for Ornithology), that 2016-17 was a big red-breasted nuthatch irruption year. Their conifer seed sources in the north had been sparse, and they were moving south in large numbers in search of native and non-native conifer seeds, including those of Norway spruce plantations.
Back in the 1990s, before the onslaught of hemlock woolly adelgids, I had often watched wintering red-breasted nuthatches in our eastern hemlocks along our stream, but those trees have been ravaged if not entirely killed by the adelgids. In this decade, wintering red-breasted nuthatches have relocated a mile and a half uphill to our one-acre Norway spruce grove.
After my first sighting of them, I rarely missed either hearing or seeing the red-breasted nuthatches in the grove, sometimes in the company of black-capped chickadees and dark-eyed juncos or sometimes on their own.
Then, on November 27, as I sat in the lower section of the spruce grove, my back against a black locust sapling, I spotted a red-breasted nuthatch flying frequently to the forest floor in what looked like nervous haste, poking about on the ground, and then flying up to a spruce trunk. I also heard another calling its nasal, tin-horn-sounding “yenk, yenk” from farther away. The one on the ground continued poking and prodding like a pepped-up robin. Suddenly, it landed on a spruce branch close to the ground, four feet away from me, called loudly, and flew back to where I had originally seen it.
Later, sitting on Alan’s Bench at the upper edge of the grove, I heard several red-breasted nuthatches calling from all directions.
Handsome, beguiling birds with bluish-gray backs and wings, rufous-cinnamon breasts and bellies, black heads, and a broad black line through their eyes with a white line above them, they were once known as Canada nuthatches (Sitta canadensis) or red-bellied nuthatches. They are closely related to the larger, deciduous-forest-dwelling white-breasted nuthatches (Sitta carolinensis). Both species climb up and head-first down tree trunks, probing bark crevices for insects, but white-breasted nuthatches are slower and less trusting than red-breasted nuthatches.
On December 1 I was decked out in orange because of rifle season, and I wondered if the red-breasted nuthatches would notice and shy away from me. As I neared my locust tree back rest in the spruce grove, a red-breasted nuthatch was busy probing in the low, dead branches of the large spruce in front of the locust and paid no attention to my flamboyant presence.
Instead, the bird flew to a nearby large dead spruce snag that had been topped in a storm and was joined by a second nuthatch that flew into the same tree. They kept their distance from one another as they ran along the dead, parallel branches as well as up the old trunk. Although highly aggressive and territorial during their breeding period, those that migrate south in the winter remain in small, stable groups with little or no aggression.
By then I was hooked on these quick, agile little birds, and almost every morning returned to the spruce grove to watch them. Sometimes there was one, sometimes two, and several times three birds. Usually they were scuttling around on the bare ground like gray mice, searching for spruce nuts detached from cone scales.
But once I saw a pair running about on a thin, fresh layer of snow. Then one snatched a spruce nut, flew low on to a tree trunk, and ate it. Mostly though, on the few days with a snow cover, they were high in the spruce trees, hanging on dangling cones, and extracting the seeds.
One January day it was seven degrees, the ground was bare, and I stood watching as one nuthatch rushed about in search of food. I marveled that its tiny feet and legs could move so quickly in the cold and that these little birds have feathers that kept them warmer than my five layers above and three below. Slowly, my upper body and feet froze as the nuthatch continued its rounds in wide circles about six feet away from my still figure.
Other folks in Pennsylvania were watching red-breasted nuthatches at their feeders. Of the 690 Project FeederWatch participants in our state, nearly half reported at least one red-breasted nuthatch at their feeders, but I never saw one come to our feeders.
I had hoped the nuthatches might stay to breed in our spruce grove, but I last heard them in mid-March calling from the spruce treetops. Here in Pennsylvania they are irregular, local breeders mostly in our northern tier, especially in the Poconos. But as the conifer plantations planted by the Civilian Conservation Corps in the 1930s during the Great Depression aged, in the 1960s, red-breasted nuthatches sometimes bred in plantations as far south in the commonwealth as York County on the Maryland border and west to Beaver County near Ohio.
Gene Wilhelm, in the Second Atlas of Breeding Birds in Pennsylvania, writes that “few counties had no records during the second Atlas period,” even though the species is still thinly distributed in the state. Most records are from the northern half of Pennsylvania in coniferous and mixed coniferous and deciduous forests and estimates of their numbers range from 18,000 to 28,000 birds.
According to a field note Wilhelm wrote for PSO Pileated, a pair of red-breasted nuthatches nested in their Butler County black spruce woodlot for three consecutive years (2011-13) and then disappeared until early last fall.
That’s when Wilhelm also had close encounters with a pair of red-breasted nuthatches. He was sitting outside writing when “the male bird landed two feet from my mobile TV tray, snatched a stinkbug from our porch screen door, carried it in his bill to a limb of a red maple less than ten feet above my head, ate the bug whole, then repeated the antic 10 times in the next 10 minutes. At that point, the female nuthatch dropped to the ground next to the screen door, and helped herself to the easy meal, too.”
That day they made 21 round trips in half an hour and ate 42 stinkbugs. And they returned for six more afternoons making “at least 89 round trips, ate at least 111 stink bugs, in three hours of hunting,” Wilhelm concluded.
Red-breasted nuthatches migrate through Pennsylvania from the second week in April to the third week in May, but those that stay to breed begin courting as early as March. The male sings his courtship song while turning his back to the female, swaying back and forth like a revolving fan and erecting his crest feathers. The pair also flies together with slowly fluttering wings or long glides.
Both sexes excavate a nest hole 2.5 to 8 inches deep in soft aspens, dead or dead parts of trees. They line their nest with fur, fine feathers, grass, hair and shredded bark. The female lays five to eight whitish, spectacled reddish-brown eggs in May.
The pair also applies sticky conifer resin at the outside and inner walls of the cavity entrance. They bring in resin globules from other conifers in the tips of their bills or on a small piece of bark which they use as a tool to apply the resin. Throughout the 12-day incubation and 18-day nestling periods, they do this as often as five to 10 times a day. It seems to be a deterrent for nest predators, such as house wrens, red squirrels, snakes, weasels and even ants, but the parents are able to avoid the resin by flying directly into and out of the nest hole.
The male feeds the female during her incubation period, both on and off the nest and while she broods the hatchlings. Both parents feed their offspring in the nest and for two weeks or longer after they fledge in late June or early July. The young birds may join their parents in mixed species flocks of resident birds and stay together as a family since they have only one brood a year.
But if it is another irruption year, they may begin heading south as early as the first week in August, although their peak migration period is between the third week in September and third week in November.
Because they irrupt every two to three years, I doubt I will see any in our spruce grove this winter. But I will forever remember the year of 2016-17 as my winter with the red-breasted nuthatches.