Many bird species inhabit northern Arizona, but none is more closely associated with the ponderosa pine than the pygmy nuthatch. Essentially, where ponderosas grow, pygmy nuthatches are found. These tiny, highly social birds are year-round residents with white breasts and grey heads and wings.
Flocks of pygmy nuthatches are often quite conspicuous as they forage in ponderosa pines, chatting with high-pitched tweets. They busily hop up and down the trunks—often hanging upside-down—and out to the tips of branches, searching for insects or hiding seeds.
Pygmy nuthatches have complex social structures. Breeding pairs get help raising their young from male relatives, often the pair’s own sons from previous years. These males help feed females incubating eggs and, later, chicks. They will also help defend the nest from predators such as gopher snakes, Stellar’s jays, …. and red squirrels, which love to raid bird nests.
In winter, pygmy nuthatches form large flocks, composed of multiple family groups. They roost communally in well-insulated tree cavities to share the heat generated by many tiny bodies. These remarkable birds also allow their body temperature to drop on especially cold nights, a sort of temporary hibernation known as “controlled hypothermia.”
A single roosting cavity may contain 100 or more pygmy nuthatches! If you're out hiking in winter around dusk, look for large dead ponderosas. You just might be treated to the sight of many pygmy nuthatches, simultaneously flying in to share a roosting site for the night.
This Earth Note was written by Steve Schwartz and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.
