For my small bird paintings, I usually like a smooth surface. So instead of using canvas (which often has a textured surface) I like to use wood panels.
The white panels shown are called gessobord. They are a composite product like masonite. They are factory gessoed with the white surface and are ready to paint on. I really like this product for my paintings.
The boards you see are maple panels. One nice thing about these boards is they have a notch in the back for hanging. So there is no need to frame. Plus the painting stands out, not the frame. So it's a very simple style. I like the organic quality of the wood also.
But to use the maple panels, I have to gesso them myself. I can't just paint with oil paint on the surface. So I will apply three coats of gesso. It's a time-consuming process. But I do like having control of the whole process.
Then I am ready to paint!