Ernie's attitude is best described as "touch and go", not only the common meaning that he changes from time to time but also a literal meaning applies as I often try to pet him in his cage and I must "go" if I don't want to get nipped.
I have been working with one winter glove on as it helps to get him out of the cage, then he usually calms down a bit. It's hard to tell whether or not he's gonna bite sometimes as it is natural for prairie dogs to greet one another with their mouths. Well, the efforts continue and the goal is to have a friendly companion who will not be nervous around me.