Nuthatches are one of my favourite birds. In part because of their extraordinary ability to walk headfirst down trees. No other birds in North America can do this. This post talks about how they do it and why.
How Do They Do That!?
First, nuthatches are not actually “walking” down the tree. They are hanging from foot to foot, but they do it so seamlessly that it appears as if they are walking.
They’re able to move like this because of their strong toes and legs. Nuthatches have four toes. Three of them face forward and one faces backwards. This backwards facing toe is called the hallux. It’s longer than the other toes and is shaped like a claw that curves downwards. This strong claw-like toe helps nuthatches cling to the bark of a tree while facing the ground.
Other birds, like woodpeckers and brown creepers, brace themselves to trees with the help of their tail feathers. But, these birds cannot climb downwards like the nuthatch.
Why Do They Do That?
As for why nuthatches do this, the leading theory is that walking upside down gives them a different perspective while foraging. This alternative perspective makes it easier for them to find food missed by other birds. According to John Eastman, “a foraging nuthatch typically flies from the base of one tree to the top of another, working the trunks from the top down.” Occasionally, nuthatches will climb up a tree as well.
Climbing downwards is an important skill because nuthatches often join other birds in winter flocks. Winter flocks offer increased protection from birds of prey and other predators. I see nuthatches most often with black-capped chickadees and downy woodpeckers. They are also known to hang out with tufted titmice and brown creepers. These birds forage in different ways minimizing the competition for food. For instance, woodpeckers and brown creepers forage by travelling up a tree. Nuthatches will pick up food items that they miss and vice versa.
More About Nuthatch Foraging
Nuthatches cache nuts and seeds to subsist on in the winter months. They get their name from the way that they open a nut or seed. They’ll wedge them in a crevice and hammer them open with their bills.
According to Ornithologist Noble Proctor, “If you have a feeder in your yard it is not uncommon to hear pounding on the side of your house early in the morning as a bird jams the seeds in between shingles and then pounds them to split the hard coat.” In the summer months, nuthatches eat insects, eggs, larvae, and spiders.
The Eastman Guide to Birds: Natural History Accounts for 150 North American Species by John Eastman.
Songbirds: How to Attract Them and Identify Their Songs by Noble Proctor