Answer: The deer didn't pick up the writer's scent.
In this excerpt, the writer describes how he was able to get a good picture of a deer in the woods. At some point, the author states that the "wind must have been right" because the deer was very close to him and yet it did not move. What the author means is that because of the way the wind was blowing, the deer could not pick up the writer's scent. This means that the deer did not get scared and he was able to capture his picture.