0ISSF. Plumage varies, breeding (MAR-JUL) and non-breeding (SEP-MAR). Breeding shows "upperparts paler, grayish to graying olive with few or no dark streaks." Note a gap in plumage, BOW notes AMPI have soft plumage that wears down and fades by July. M/F similar. Observed at top of mountain hike in Denali NP but no photo.