Its characteristic is to walk downward, which all the other birds can't do.
Some say you can tame a curious bird such as nuthatch or chickadee easily. One time when I was out in my backyard, a young nuthatch saw me peeking through a camera lens. I got a bit closer, and the nuthatch even came closer hopping to me!!!
Here it is. A very close look of a curious young bird
(too close for a telephoto lens)
A male has a black cap, while a female and a juvenile have a duller cap and paler underparts.
It likes to eat sunflower seeds.
On a snowy day, it comes here to find its favorite suet.