Nice composition and the winter colours look good, however the owl's face seems to be just a an area of white without very much detail so it is tough to tell how sharp it is. I'd like to see more detail in the face.
Great vertical composition, fits the height of the grasses well. Nice relaxed pose on the owl. The only thing I could see considering here is ditching the yellow border on the image...a touch distracting vs enhancing imo. Details on the owl look just fine to me considering the light quality and size of the subject in the frame/working distance. I like that big tuft of (goldenrod?) above the owl's head....looks like a hat :)