The White-breasted Nuthatch is a jovial little bird despite being neck-less. But the bird is not feckless. The industrious nuthatch uses its sharp bill to “hatch” seed out of nuts, and pry insects and seeds from branches every which way. One of its goofiest poses is when the bird ends up facing you straight away and its curious eye position becomes apparent. Since the nuthatch spends most of its time on trees and branches, it makes sense for its eyes to be narrowly placed, looking upward and out for predators.
White-breasted Nuthatch. Photo by Arlene Koziol
In the Madrean Sky Islands of the Sonoran Desert, it has been demonstrated that White-breasted Nuthatches are under the selective pressures of these isolated “islands,” and show adaptive traits apparently tailored to climatic extremes. However, under a warming climate, these unique resident birds will likely have nowhere to migrate. Under a 3 degrees Celsius warming scenario, almost the entire Madrean range could be wiped out, and the unique genes and adaptations of these Madrean birds could be lost.
Looking at the range of nuthatches across the United States, a few curious gaps emerge. Avoidance of hot summer weather during the breeding season seems to play a part in this range, but research has also found that the birds evolved with the pine-oak woodlands of North America. Eating seeds and nuts, the pine-oak woodlands offer tremendous mast crops from the dominant trees while also providing a vast array of shrubs and fruiting herbs in the understory. Many populations roughly follow the outline of this ecosystem, and even within the Madrean Sky Islands, the birds only live at or above the zone of oak woodland.
Oak savanna at Faville Grove Sanctuary. Photo by Brenna Marsicek
Just this week, we’ve noticed an influx of White-breasted Nuthatches at Faville Grove. Perhaps these are juvenile birds, noisier than before, or maybe we didn’t listen carefully enough in previous months for the rapid “chuckles” of these nuthatches. Another possibility, backed by some recent preliminary research, is that northern birds from Canada are seasonally moving south. Nuthatches are year-long resident birds, but this may not be the case everywhere. Eastern nuthatches appear to cycle every two years on these apparent irruptions when they run out of food in their northern range and head south, possibly looking for increased acorn crops. Observations of banded birds would tell a more concrete story, but it’s interesting nonetheless to think of such a common resident bird in these new dynamic terms.
You can find White-breasted Nuthatches in oak woodlands and savannas at Faville Grove. I’ve seen them in flocks with chickadees, but apparently the nuthatches also enjoy flocking with the observant and noisy Tufted Titmouse; when the titmouse is absent, research has shown nuthatches to be on extra high alert for predators–keeping those goofy eyes skyward, the same as their relatives on the Madrean Sky Islands.
Written by Drew Harry, Faville Grove Sanctuary land steward
Cover photo by Mick Thompson
