Each fall, Northern Shrikes migrate south from their breeding grounds, to fairly open habitats across the northern United States. Most Northern Shrikes that migrate to the southern edge of their range are first winter birds. Over time, due to feather wear, the barring on first year Northern Shrikes wears off. When you see these birds early in the fall they can look quite different than what you will see in the spring!
Here are a couple photos (taken Oct. 22) of a fairly "fresh" individual.