Fox appears in daylight, and the poem seems to insist on seeing it as a living animal, not as something to wear. The title, "Pelt," points to the fur a fox might become, and the second line pushes that idea away: the fox is "not like a neck fashion." The speaker seems to be correcting an image that comes too easily, the fox as a collar or stole.
Instead, the poem reaches for a different comparison: the fox is "wild as the ivy / on a high burn." A "burn" is a small stream in Scots usage, so the picture is of ivy growing untended on a steep, out-of-the-way bank. Nothing about that is tame or decorative.
The mood is quiet and a little defiant. The speaker doesn't shout; they simply look and refuse the tidy comparison. There is admiration here, and a sense of relief in letting the animal stay free. The short lines and gaps make the poem feel like a glimpse, as if the fox might be gone by the time we finish reading.