I hadn’t known this until I caught it on camera, somewhat accidentally, but nuthatches cache seeds for eating later. I’m not the first, by a long shot, to observe this and many small birds — like chickadees and woodpeckers — will do the same. Still, it is neat to see the behavior with your own eyes.
I’d have taken a few more frames if I knew what was happening at the time. However, it’s 10F or so in Huntsville and I was getting cold standing there with my camera.