Inverted Invaders

Red-breasted Nuthatch, pausing in mid-invasion on a backyard bird feeder.  Photo by Kenn and Kim Kaufman.

All across the northeastern and central U.S., an invasion is under way. This invasion has gone unremarked by the traditional press, but those who pay attention to the real world have noted a huge invasion of tiny birds. Hordes of Red-breasted Nuthatches are creeping southward, possibly pausing in a back yard near you.

North America has four species of nuthatches (family Sittidae), small birds that clamber up, down, and around tree trunks - our only birds that regularly go down trees headfirst. Three of those nuthatches are mostly sedentary, but Red-breasted Nuthatches are famously nomadic. When the cone crop is poor in the boreal forests (roughly every other year), these upside-down birds forsake the north woods in early autumn and sweep toward the south. Although normally they favor evergreens, in migration they may show up anywhere, and they quickly find bird feeders stocked with sunflower seeds, suet, or peanuts.

As I write this in late September, the nuthatches are still concentrated in the northern states, but it appears this may be one of the larger flights of recent decades. For a look at Red-breasted Nuthatch incursions of past winters, you can make your own graphs and tables of the results of Audubon's Christmas Bird Count for any species through the Audubon web site. And while we wait for CBC season to roll around, fill up your local bird feeders and watch for these little nasal-voiced, acrobatic, upside-down invaders to show up.